[Image] [Image] Forge and Burner Design [Image] A "Links2Go Key Resource" Page [Image] I am about to forge-weld a Spontoon pipe-axe head. (This excellent image was taken by my apprentice, Kevin Brown) (Click picture for full sized image.) Me in my Utilikilt - superior wear for blacksmithing. [Image] Me, the Z, and Kilt The Z & My Daughter at the Hagerman National Fish Hatchery [Image] Warning! [Image] I provide the following information as a service to the blacksmithing community. Although the designs I employ in building my burners and forges are safe and reliable in the way that I use them, the same may not be the case for you. You assume all risk in using this information, or any other information on this page. Other designs that I have posted here have been submitted by other smiths, and I have no experience with most of them. Use care and good sense in using any of these designs. Get help from a knowledgeable smith if you are new to this work. Don't take chances because these tools can cause injury, blindness, or even death, if used improperly. Also, be sure you are in a well ventilated space (see the Nighthawk CO & explosive gas detector paragraph), or better yet, work outside. Additionally, never operate a forge that is connected directly to a propane tank that is near a forge, or indoors. An emergency pressure valve release could instantly place you in the middle of a fireball. Follow all local codes regarding indoor use of propane, and I believe indoor use of a propane tank violates code everywhere in North America, and most of Europe. A new concern has arisen with the introduction of the "Mongo Burner Series." Please read carefully all the information in the separate "Safety Warnings and Considerations" information which heads the "Mongo Burner Series" section. Thank you. [Image] An additional item that should be of interest to you is obtaining an explosive gas/CO detector for your working space. Mark Manley, of "Manley Metal Works," Silverton, Oregon, provided a short piece of very important information in the Winter 2000 issue of "Hot Iron News" that I feel needs to be passed on to a wider audience. There is a very reasonably priced digital read-out combination explosive gas and CO detector available in local hardware, building supply, and other stores. I was concerned about having a CO monitor in my shop, even though I have a very efficient induced draft hood in my shop. The detector is made by "Kidde Safety" and is called the "Nighthawk." I will not go into the specs for the instrument here, it is available on the Internet if you look up "Kidde Safety," but I will say that it is a very finely designed and built instrument. It runs on 110 VAC, and has a 12 VDC back-up. It plugs directly into an outlet, or the transformer plug detaches for remote mounting up to 6' from the plug. You can easily check your CO level with a quick glance at the digital read-out, and if it detects any kind of flammable gas it will instantly sound an audible alarm, and the word "Gas" will show on the digital display. If it detects CO, it will sound a different audible alarm and display the PPM level. Also, you will know it's operating because the blinking decimal point in the digital read-out indicates it's operating and sampling the air in your shop. [Image] I bought one of these instruments for my shop, and was so impressed with it that I went down and bought a second one for my home, which has natural gas heat, gas hot water, and a natural gas fireplace insert. I priced CO detectors on the McMaster-Carr web site, and they alone were $170, where this combination instrument is only $59 at my local Home Depot. Considering how deadly CO can be, this instrument is very inexpensive, well worth the investment, and it may well save your life. After Mark installed his "Nighthawk," he discovered that he had been exposing himself to CO levels of 30-160 PPM for a long time while running his forge! Thanks for the tip Mark. Note: There has been a recall of Kidde Safety "Nighthawk" gas and CO detectors. This does not affect any detectors sold after the date that I posted the above information, however you may check your unit by going to http://www.cpsc.gov/cpscpub/prerel/prhtml99/99082.html. ------------------------------------------------------------------------ A Word About Obtaining My Help [Image] I am no longer able to offer my support to help solve problems you may have with your burners or forge. I have reached the point that something has to give. Two to three hours a night answering questions has brought my metal working each evening of the week to a stand still. I will continue to update my blacksmithing pages, and will now also have the time to clean out all the outdated and conflicting information in my pages, however, I will no longer be able to troubleshoot your system. I still want to receive your e-mails if they do not pertain to forge or burner problems. If you build your burner to the design specs and information shown and discussed on my pages, including in the Troubleshooting Document and FAQ, your burner should work well. If it doesn't, then its not built correctly, and you will need to make some adjustments after looking through the available information. The best thing to look at when fine tuning your burner are the various flame images I have posted. If yours looks like these images, you have it right. Here are a few helpful links. Note: If you e-mail me, please be sure your e-mail in "txt" (text) format, not html. I am now averaging two to three virused e-mails each time I download my e-mail, so I have to be very careful. If your e-mail is not in "txt" format I will most likely delete your e-mail without opening it in order to protect from possible virus infection. Its certainly sad that we have idiots in our society that feel they must cause such problems. FAQ Forge & Burner Troubleshooting Document Some Often Asked Questions EZ-Burner Construction Rich To Lean Flame Image 1) T-Rex Flame Image - Ideal Neutral Flame 2) Side-arm Burner Flame Using Temporary Cast Iron Test Nozzle - Slightly Reducing Flame 3) Another Flame Image - Oxidizing Flame [Image] The bottom three flame images give you views of burner flames adjusted to 1) neutral, 2) slightly reducing, and 3) strongly oxidizing. The burners have nothing to do with it, just the choke settings. All of these images could have been done with the T-Rex, or Side-arm burners. At your high end gas pressure, if you have achieved a flame similar to the oxidizing flame shown in the bottom image, #3, you will then have full control over the burner flame across the full pressure range. This will allow you to achieve oxidizing, neutral, or reducing, flames as needed by simply adjusting the choke. You will then have a properly functioning burner. ------------------------------------------------------------------------ New Additions to My Site or This Page [Image]My Shop at a Glance[Image] Golden Age Forge Gallery News...ITC-100 Needs Recoating Periodically! Iron Wheel Carousel Tongs Rack Explosive Gas/CO Detector My "Dream Shop" Becomes a Reality...a Narrative of its Construction ------------------------------------------------------------------------ My Home Page, & Forge Related Pages on This Site The Gallery My Shop at a Glance My Shop Construction Page My Home Page Wrought Iron for Sale Why Build A Gas Forge? Forge and Foundry Page Construction of the Freon Tank Mini-forge Forge and Burner Troubleshooting So You Want to Forge a Sword The Rex Series of Burners The Best of "Theforge" - a Zipped Download of All Three Files -or- The Best of Theforge - Vol 1 The Best of Theforge - Vol 2 The Best of Theforge - Vol 3 ------------------------------------------------------------------------ Page Index (Click link to jump to desired topic.) New Additions Safety Warnings Explosive Gas/CO Detector TWECO Tip Modification The Reil & EZ Burners (These are the standard burners) The Mongo Burner Series -Safety Warnings and Considerations for the Mongo Burners -Burner Efficiency VS Economy -The Mongo & Side-arm Burners -Minimongo Burner -Micromongo & Nanomongo Burners -Nanomongo Burner Forge Design Rules of Thumb Sources for Refractories, Burner Nozzles, & T-Rex Burners -Sources for Refractories -Obtaining Premade Burner Flares -The "T-Rex Burner" -The "Shorty Burner" Download the BTU Output Calculator Will Gas Forges Weld? How Hot Can These Burners Get? Misc. Burner Chokes Axial Burner Choke Additional Burner Designs -The Monster Burner -Bienstock Burner -Jay's Burner -The Wasser Modification Gas Forge Designs -My Four Burner Forge Some Additional Gas Forge Designs, 1 through 4 -Sandia Recuperative Forge Design -Clamshell Forge -Building a Large Gas Forge Forge & Burner Design Links Coal Forge Designs Additional Coal Forge Designs & Brake Drum Forges Blacksmithing Terminology Closing ------------------------------------------------------------------------ A Preface for All Burners on This Page The "TWECO 14T Tip" Modification [Image] Work by Michael Porter in Seattle has resulted in a powerful modification that I recommend you apply to any of the burner designs on my pages. Instead of simply drilling the desired jet hole in the burner tube, you can achieve far superior results by drilling and tapping the jet hole location to take a 1/4"x 28 threaded "TWECO 14T" copper tip, available at your local welding supply shop. There are a variety of these tips in various jet diameters and external configurations available. You should try to obtain the Tweco tip configuration that measures 1-1/2"x 1/4," and has a long tapering nozzle tip. With this arrangement you can easily experiment with various tip openings simply by switching them as desired. Once you determine which tip performs best for your particular application, then you should silver solder it into place to prevent any possible gas leakage past the threads. Because of the high temperatures that the jet tip may encounter, due to occasional chimney effects, you should not use any other lower temperature process, such as teflon tape or soft lead solder. Another comment that applies if you are modifying the "Reil or EZ Burners" regards the bell diameter. The increased suction created by this tip modification will require that you increase the intake bell to a 2" diameter, or you will not get enough intake air to achieve a balanced burn. If you have any questions regarding this modification, please contact Michael Porter, the smith who perfected this modification. [Image] An additional consideration that I need to mention, and which is covered in detail in the "Safety Warning" section at the top of the Mongo Burner information, regards UV radiation hazard. The Tweco tips increase the efficiency of the burners and their output temperature. In the Mongo burners the temperatures are up into the middle UV temperature color range, and it is possible to get "flash burns" from the light coming out of the forge. Be aware of this potential hazard with any burner you modify to use this tip. UV radiation is very damaging to eyes and skin. ------------------------------------------------------------------------ Propane Forge Burners The Reil & EZ Burners [Image] (Reil Burner Modification) Be sure to read the FAQ that goes with this design also. [Image] The burner design above is my modification to the well known "Aussie" burner, as designed by various smiths, some noted on the drawing. This is a superior burner in all respects. It will sustain a controlled flame with propane input pressures of over 50 psi. The cost of building it averages about $5 US, and is constructed of all "off the shelf" plumbing parts available in any hardware store. The FAQ explains its construction, but is not a detailed step by step instruction sheet. It is a collection of suggestions and observations that would be of use if you decide to build one. This document also includes a section on tuning your burner. [Image] NOTE: I have now included an additional "EZ-Burner" design that you may find much easier to build. It eliminates the difficulty of doing the flare in the nozzle, and also eliminates three of the drilled and tapped holes. I am not including a drawing for this modification as it is not necessary, but I do have an image of the burner if you are interested. The "EZ-Burner" HTML document linked above should provide all the information you need to build this quick and easy burner. It should only require a couple of hours to complete it. I would like to include one additional note about galvanized pipe. By all means do use it for your burner. It will not get hot enough to bother the galvanizing over most of its length, and if it does, you are doing something wrong. Properly used, the burner should be cool enough to handle at all times, except for the 1" diameter nozzle piece at the end. The galvanizing will protect your burner from rust. If it does get hot enough at the end to burn off the coating, the tiny amount involved will not cause you any problems. Also, do not use any pipe joint compound in the 3/4" joint, it's just not necessary, or of any value. [Image] I used four of the flared nozzle burners on my 24" long cylindrical forge, but one or two would be all that most smiths would require. I live at an elevation of 2300 feet, and can easily weld with only one burner at 6 psi propane pressure. If you would like to see more images of this forge, please go to my Forge and Foundry Page linked at the top of this page. Thank you. [Image] Use of Natural Gas: You may use this burner for natural gas applications, but will have to increase the jet size in order to do so, and you will require 10-20 psi natural gas pressure. I know of at least two smiths currently doing so, but I do not know the jet diameters they are using. If you use this design for natural gas I would very much appreciate knowing your jet size so I can add that information to this page so others may benefit from your work. Please e-mail me. Thank you. [Image] I was contacted by Ray Maiara concerning the use of natural gas. He is using natural gas at only 1/3 psi pressure, and has had to go to a very large "jet" size, about 1/8", and is using a blower, so this really doesn't fit in the category of a ventouri type burner. He has also gone to very large plumbing diameters, main feed of 1-1/2", and forge lead in of 3/4", to gain as little restriction on the gas flow as possible. If you are considering the use of natural gas, contact your gas utility and ask them if they can provide you with a high pressure feed. My gas company will provide a high pressure tap off the household service, up to 80 psi, and there is no additional service to pay for, nor is there any charge for the work to install the high pressure tap. I do have to buy the additional regulator however. It is worth your time to check into, since this burner will function with natural gas if sufficient pressure is available, but again, you will have to experiment with the jet diameter to find the proper diameter, given your available pressure. You must have enough pressure for the ventouri action to operate correctly to draw the air into the bell. Remember that natural gas will not provide as much heat as propane, so your forge may not be able to forge weld. [Image] A properly adjusted gas forge will have an air/gas mixture that will create a neutral, or slightly reducing, environment inside the forge. This is necessary to prevent excessive oxidation and scaling of the metal. With my burner design, the forge environment should meet that requirement if you use a #57 or #58 jet diameter. I have found that my forge needs no choke or intake air controls, and runs with a slightly reducing atmosphere as desired. If you want a very simple and extremely efficient burner use the modified Aussie design. If you build it with the Bordeaux modification you will have the greatest versatility for adding a blower, or intake air controls, if you feel you need them later. [Image] A lot of people ask about what a proper burner flame should look like. Thanks to Don Foreman, I now have an excellent image of a virtually perfect burner flame. Your color intensities may not be quite as dramatic as in this image, but otherwise this is what you are attempting to achieve. Notice the perfect symmetry of the flame, which is an indication of a well centered jet. A flame that tends to burn to one side is an indication that the jet is not aligned correctly. You may click on the image for a larger view. [Image] (Image courtesy of Don Foreman) [Image] Rupert Wenig has provided an excellent sequence of six images of his Minimongo Burner showing the effects on the burner flame of opening the choke. I have combined them into one image. The images on the right were taken without flash to show the flame characteristics more clearly. This is a very instructional image, and should be extremely useful when you are tuning any kind of burner, not just the Mongo or Minimongo. You want to achieve a neutral flame as shown in the center image. Note: The coupling that Rupert is using for his flared nozzle has been machined out to have a 1:12 internal rate of flare...it is not just a coupling. Being cast iron it would also melt in an actual forge or furnace application. This is for test purposes only. Use stainless steel. ------------------------------------------------------------------------ The Mongo Burner Series [Image] The 2-1/2" Diameter Mongo Burner The Mongo Burner Series: Mongo Burner = 2-1/2" diameter burner tube Minimongo Burner = 1-1/4" diameter burner tube Micromongo Burner = 3/4" diameter burner tube Nanomongo Burner = 1/2" diameter burner tube [Image] Safety Warnings & Considerations....a Must Read: The Side-arm burner has now been perfected and can be found at the bottom of this section. You are building and using this burner entirely at your own risk. If you don't wear eye protection, and you loose your eyesight due to the UV radiation that these burners can produce, then you are responsible for not reading and following the warnings, and must bear all consequences. I will not accept any liability for the stupidity of the builder and user of this device if he should injure himself with it by ignoring this warning. Please read the following e-mail I received. It will give you an idea of the temperatures these burners can achieve. "At this point, my only observation is that the (Micromongo) burner is too hot for the current nozzle design. Don't get me wrong, the burners worked great. I could not get the burners to run quite right without Larry Zoeller's nozzles, but I did not try very long, as I had a job that I had to get done this weekend ( I was already behind because I could not get enough heat out of the Reil Burner ). After going down to the welding store to buy a shaded full face plate (a definite necessity), I got right to work. Things were going great until the burners went erratic. The problem was that the nozzles got yellow+++ hot and sagged over the end of the burner. The nozzles now look like a tuba run over by a semi. I can not wait to get some more nozzles from Mr. Zoeller so I can form up some type of ceramic nozzle and start experimenting with this burner. Great potential. Thx's for all the help. Fred jyblood@nwi.net" [Image] There are a few more items to address. It is apparent in our testing that these burners display a very wide range of behaviors depending on what jet diameter is employed. Also, we are now using the long tapering copper 14T Tweco tips for our jets, even on the Reil and EZ-Burners, which I strongly recommend you do also due to the greatly increased performance they afford. I suggest you experiment with various diameter orifice Tweco tips and settle on one that works best for your particular application. See the FAQ for a listing of nominal to actual orifice diameters for these tips. They are threaded, 1/4"x 28 thread, so you can easily switch them for experimentation. I may post a "recommended jet diameter" later on for each burner size, but presently I want to leave it open ended, even though the Mongo and Minimongo Burners both have jets called off in the information below which will provide a good starting point for you. Additionally, the tapered nozzle stainless steel flare operates at a much higher temperature, a red heat, on the Micromongo Burner than on the Reil or EZ Burners. This increased temperature will cause much more rapid degradation of the burner flare, even if its made of stainless steel. In fact I would say that stainless steel is your best option for metal nozzles, and even their life may be fairly short, although proper mounting of the nozzle 1" back into the Kaowool will greatly extend its life. I am getting more than three years out of a nozzle presently. You may want to consider casting your nozzle flare into the wall of your rammable refractory shell, if you have this kind of forge lining, thus eliminating the metal nozzle all together. This would be an easy task to perform, and may be the very best alternative for these high temperature burners. Another possibility is coating the nozzle, either stainless or black iron, with ITC # 213. Have fun and be careful! [Image] A Note about Economy vs. Efficiency: There are numerous comments in my pages about "economy" and "efficiency." They do not mean the same thing. As I use these terms, the economy of a burner refers to how much its going to cost you to run it. The efficiency of a burner, in the way its used in my pages, refers to how much air it can draw in due to the strength of the vacuum it creates in the intake bell or ports at a given gas pressure. There are only so many BTUs available in a pound of propane, and no matter what you do you can not get any more than that out. If two different designs of burners are both running with a totally neutral burn at 100% combustion, and maintaining two identical forge chambers at the same temperature, their economy will be identical. The Micromongo Burner can produce higher temperatures than the Reil Burner, but it uses more fuel to do this. If you lower the output of the Micromongo so that the temperature inside the forge chamber is the same as in an identical forge chamber heated with a Reil Burner, the fuel usage, or economy, should be the same. If they are not, then one or the other is not running at optimal tuning. So don't choose the Micromongo Burner because you think it will save you money, it won't. It will give you the ability to get the same economy as provided by the Reil Burner, but it will also allow you to reach higher temperatures than the Reil Burner can attain, but this will cost you more in fuel usage. There is just no free lunch. It is likely that overall you will spend more money on fuel with the Micromongo burner because you will probably want to use that extra heat range to run a hotter forge. You pay for what you get. Note: We were very surprised by the results of some recent side by side tests of the T-Rex and Reil burners. They both consumed about the same amount of fuel, yet the T-Rex was much hotter. We concluded that the mixing and fuel/air ratios in the T-Rex are superior, and provide a better burn, thus extracting more of the BTU heat value from the fuel than the Reil burner is capable of doing. The T-Rex is both more economical, and more efficient. It is more econimical because it can be run at a lower gas pressure, using less fuel, and obtain a comparable temperature in the chamber. [Image] The only exception to the basic statements above may be when using a Mongo Series Burner, or one of the big Rex series burners, to run a melting furnace. If you are able to achieve a higher temperature in the furnace with a bigger burner, it will achieve the melt more quickly, which cuts the time available for heat to escape through the furnace walls and up the stack, thus wasting fewer BTUs. However, the higher temperature creates a greater thermal gradient across the thickness of the furnace wall, increasing the amount of heat loss in a given time, so there is a trade-off to consider. If the Furnace walls were made of 100% efficient insulation this relationship would not exist, and the burners would perform with equal economy, but perhaps not convenience. I point out these various relationships to show you that things are not as simple as they may sometimes appear. There are a lot of factors to take into account when discussing economy of a burner. For the most part, the smith operating the forge, and the quality of the forge, will be the most important factors in determining overall economy, not the burner. Think about running your burner to do a day's forging, without the benefit of a forge chamber, and you will understand my last comment. The Mongo Burner & New Side-arm Burner Note: For historical purposes, and to keep information available that may be of use to someone, I have not removed the drilled air intake hole Mongo burners from this page, nor the old Side-arm information shown several paragraphs below. The drilled hole ports are too small to provide the necessary intake air volume on the original Mongo burner, resulting in a very rich burn and high CO production...potentially dangerous. The original Side-arm burner design has also proven to be an inferior design if built as shown in this drawing, and I do not recommend it. There is now a far superior option available which turns the Side-arm burner into to a very fine burner by using an asymmetric T-fitting. If you enlarge the "intake" bell opening, as shown in the images linked a couple sentences below, the inlet "R" value will drop to a level to allow these burners to perform extremely well, especially if you use a Tweco 14T jet tip. Larry Zoeller has been experimenting with this concept and has provided some examples of high quality Side-arm burners. Check these out if you want a good example of these very easily and quickly made burners. Paul Pirtle has also been working on these burners and has produced an excellent Side-arm burner, shown with "axial" choke installed, which performs extremely well across the entire pressure range. He has since replaced the cast iron test nozzle with a stainless steel nozzle so that it will not melt in his forge chamber. Please do not use cast iron. The following are a few comments Paul sent me regarding his excellent Side-arm burner. I include it here because the jet orifice information may be of use to you. "Yesterday I built two air choke assemblies, using a 1-1/4" short nipple with round choke plate, 1/4-20 all-thread, and a brazed T per your design. Tested both, they work perfectly to adjust flame to blue/green transition. Based on how far the choke needed to be closed I think I could run a larger than .035" orifice. I tested the .023 orifice again with choke, it runs fine but fussier than the .035. I am guessing it might be marginal to small for the 3/4" burner tube. A 1-1/4"x 1-1/4" x 3/4" cast iron T-fitting is necessary to provide the needed intake air flow volume for a 3/4" burner." (It may be possible to use a smaller bell on the top end of the fitting where the jet pipe enters, perhaps a 1" x 1-1/4" x 3/4" or even a 3/4" x 1-1/4" x 3/4" fitting. Ron) [Image] The original Mongo burner is a huge multi-purpose "Jet Ejector" burner. I was so impressed after I built one, even though it had a too short burner tube and no nozzle, that I felt it deserved a place on this page. I named it after "Mongo," the giant in "Blazing Saddles," because of its huge size.... 2-1/2" diameter bore! It is a different design of burner, having seven 1" diameter air holes in the barrel of the burner, and an axial 1/2" diameter internal jet tube, but it works quite well, except for not being able to get a fully balanced fuel/air mixture. It tends to run on the fuel rich side due to the small intake port area and resulting insufficient intake air volume. When I first tried test firing it I was unable to run it below 20 psi or it would become erratic and run extremely rough. I switched out the jet tube for one 1" longer, to get the jet just slightly downstream of the air intake openings. This made a huge difference. I can now run the pressure down to zero gage pressure, doesn't show on my gage at all, but it is probably about 1/10 psi, and it purrs away just beautifully at a very reduced output. This low end operating range is due to the 28:1 induction ratio of jet ejector burners, as compared with the 20:1 ratio for the linear inducer burner like the "Reil or EZ Burners." This burner has tremendous adjustability in its output, making it useful for kilns, but the possible CO dangers need to be considered and precautions taken. For forge use, I strongly recommend going to an asymetric Side-arm design as shown at the top of this section, and use of a flared nozzle. [Image] The original Mongo burner design discussed in the paragraph above was sent to me by Richard Mize, in Kentucky, and I have to thank him very much for sharing it with us. He included some additional information and suggestions in his drawings which I too included in the packet of drawings. I did not build the refractory ventouri throat, nor the bracket he suggests, at least not yet. I have simply run scans of Richard's hand drawings and posted them below for download. It is a zipped file containing 6 images, including an assembly drawing, text comment sheets, refractory ventouri throat, mounting bracket, mounting suggestions, and a list of materials needed. I have reduced them in size to allow downloading to be faster, but all together they are still 264K in size. These are hand drawings with hand written notes. They were plenty good enough for me to produce a dandy burner, and I am sure they will work just as well for you. An alternative that I strongly recommend due to its small file size is the "pdf" Adobe Acrobat file I have available also. This is a single fine quality drawing, with fewer notes and comments, and it is a much smaller file. It should be plenty detailed to allow you to build the burner without problem. Click on the gif "preview file" to see a reduced size image of the "pdf" construction file. The preview image may be all you will need to build this burner, but the text is pretty small for older eyes like mine. I do want to say that I strongly suggest the Side-arm burner discussed above, which is easier to build and produces a fully balanced fuel/air ratio, and no CO danger if adjusted correctly. [Image] Alternate Side-arm Design: (Note: this is older information, but is preserved for its historical value. Please see the latest Side-arm information at the top of this section.) You can build this burner more easily if you substitute a large "T" fitting, see link, in place of the pipe coupling. The burner tube screws into one arm of the "T", and the reducer and jet tube into the other arm. The air intake is provided by the opening in the base of the "T" fitting. You will not need to drill the big air intake holes this way. Also, it can be easily choked using a butterfly choke design, or an axial choke design, which is placed in the "foot" of the "T". You will have to experiment to determine the proper length of axial jet tube in order to place the jet in the right location in relation to the incoming air. I have not tried these modifications to the burner design. (Thanks goes to "Frosty" in Alaska for this suggestion, and the induction ratio information above.) Robert Grauman has built one he has named the "Side-arm Design," in the Minimongo diameter, and this is what he has to say. (Note: I strongly recommend using a 1/8" jet tube, instead of the 1/4" tube shown in the drawing.) "I used to have a choke plate in the air tube, but I found I was getting a neutral burn with the choke wide open, so I removed the choke, and am now running with the inlet wide open. This has simplified the burner considerably. I am using a #55 (0.052") jet at about 22 psi. The flame burns near neutral (I think), but it requires a flame holder on the end of the burner tube when the burner is not in the burner port of my crucible furnace. It burns quietly. If provoked, the flame will burn back in the burner tube, but I believe that the burner tube is too long. I will start experimenting in that area tomorrow. The burner seems to work best with the jet cantered on the air tube, but it is non-critical." [Image] Please note that Robert uses the burner in a cast iron and aluminum melting furnace, not a forge. You will want to operate at much lower pressures for forge work. Note: From tests done by Michael, it appears the "Sidearm" design is not a good choice for the smaller Micromongo and Nanomongo burners. He was unable to achieve a stable flame over a range of gas pressures in his Sidearm Micromongo test burner. [Image] Note: There is one important error in the Adobe Acrobat "pdf" file below. The jet opening should read "#52 = 0.0625" diameter", not #58. This is a very important difference. Preview the Following "pdf" file as a Reduced Size "gif" Image Download a Single Complete Design File in "pdf" Format (Recommended - 16K) Download all Six Construction Drawings in Zipped "gif" Format (264K) (Before condsidering the construction of any of the Mongo series of burners, please read the informationa about the Side-arm burners at the top of this section.) [Image] If you don't have "Adobe Acrobat Reader" on your computer you may download it here, its free. [Image] "Minimongo Burner": I received a communication from Rupert Wenig regarding a half scale version of the Mongo Burner that he is using to fire his cast iron melting furnace. His experimentation work is continuing, but here are his latest design modification details. He is getting good results with it using these parameters. See the cast iron test melt results below the following specs Rupert provided. For forge use, I strongly recommend going to an asymetric Side-arm design as shown at the top of this section, and use of a flared nozzle. -Burner tube: black iron pipe, 1-1/4" diameter by 12" long -Jet: #56 drill = 0.0465"diameter (You may need to experiment further to determine the optimum jet opening) -Air induction holes: 13/16" diameter -Additional changes in Rupert's own words: "I also changed the pipe bushing to a standard easier to get one. As pipe bushings are not normally solid I made a plug to fit the inside of the bushing to give the fuel pipe more surface area to hold it straight. I then drilled a clearance hole through the plug and bushing and installed a set screw to clamp the fuel pipe in place. This allowed adjusting the position of the fuel jet. Another change I made for convenience was to thread the inside of the fuel pipe so that I could use the jets I had on hand." "PS. There is no question that this burner is quieter than other burners I have tried." [Image] Rupert's Cast Iron Melt Results Using the Minimongo Burner Without Flared Nozzle: I did a cast iron melt with the Minimongo today. I ran the furnace for 1:12 hrs, melting 15# of cast iron while running the burner at 20 psi after a 2 min. warm up from a cold start-up. That equates to about 0.21 lb/min. From my logs the Monster burner melted 17 lb. in 1:13 hrs. This equates to 0.23 lb./min. Unfortunately, the casting didn't turn out because I got impatient. I should have superheated the melt for another 2 or 3 min as the casting I poured was a very thin section (1/4"). I would say that this compares favorably (with the Monster burner) as the Minimongo has a #56 jet in it while the Monster burner had a #54 jet. [Image] Based on the latest information I am receiving, you will need to make a 1:12 tapered nozzle flare, for the Minimongo burner, and probably for the Mongo Burner as well, once it has been fully tuned. [Image] Thanks to the work of Robert Grauman in "Sunny Alberta," we now have a very fine jpg drawing of the "Minimongo Burner" that Rupert has provided information for. You may click the link below to view the design drawing. This drawing incorporates all of Rupert's modifications to the full scale version, including some details he did not mention above. Thanks Robert. Mongo Burner Half Scale Design Drawing (Note: I strongly recommend using a 1/8" jet tube, instead of the 1/4" tube shown in the drawing.) [Image] Choke Settings Image: The below linked image is a composite image of six images Rupert sent me of his Minimongo Burner, photographed at three different choke settings, rich, neutral, and lean. All the images were shot at a gas pressure setting of 10 psi. The images on the right were taken without flash to show the flame characteristics more clearly. This is a long needed set of images that are very helpful when attempting to tune any kind of burner for a neutral burn, not just the Mongo or Minimongo Burners. Note: The coupling that Rupert is using for his flared nozzle has been machined out to have a 1:12 internal rate of flare...it is not just a coupling. Minimongo Showing Flame Under Different Choke Settings at 10 psi Gas Pressure (Be sure you also look at the full output image) [Image] Micromongo and Nanomongo Burner Designs: We now have good Micromongo and Nanomongo Burners in operation, and the development work is complete. Michael has performed virtually all the development work for this burner, while communicating and discussing possible alterations and modifications with me. I credit these burners to his tireless hours of modification and development. For the Micromongo Burner, Michael suggests starting with a #65 jet diameter. This appears to be a good jet diameter in his test burner, but we may modify this recommendation after the burner undergoes an extended period of "on the job" testing. Absolutely do use the 14T Tweco tips discussed above, and the movable tunable jet pipe modification shown in the Minimongo Burner design images. (Note: I strongly recommend using a 1/8" jet tube, instead of the 1/4" tube shown in the drawing.) [Image] Nanomongo Burner: I am posting an image of the prototype Nanomongo burner if you are interested in where we are going with this design. Michael came up with this version, and it has good operating characteristics. The burner is totally stable from zero psi gage (the needle was resting on the peg in both of my test jig gages), to 30 psi plus. In the image the burner is burning at a pressure of 10 psi, but due to the sunlight you are unable to detect any flame in the nozzle. The burner is 100% copper and brass, with a high chromium stainless steel nozzle. The interior of the nozzle is machined to a 1:12 taper, but it additionally has a "step" of about 1/8" where it meets the end of the burner tube to increase the diameter a quarter inch, the same as the normal flared nozzle does on other burners due to the 1/8" thickness of the burner tube wall. We found this "step" to be necessary due to the thin wall of the copper pipe. It turns out the "step" is a critical part of the flare's operational design. We have determined that the secondary set of smaller air intake holes toward the rear of the burner are not necessary, and will not be included in the next version. The entire air intake assembly will be shortened and simplified. It will also include a sliding sleeve choke, although the present version displays an apparently neutral burn across its entire operating range, at least as much as I can determine at this point. The four screws in the forward part of the intake are to precisely align the jet, and will be moved toward the rear and reduced to three in number in the next version. The jet orifice is a 0.023" diameter, 0.60 mm, Tweco tip, silver soldered on the end of a 1/8" brass jet tube. There is also a set screw in the back of the rear of the burner to lock the jet tube from forward or backward movement. [Image] Michael determined that this burner had to be modified with a larger intake diameter, in order to draw in the necessary quantity of air to balance the gas volume. The burner tube diameter is 1/2," and bells out to 1" in the intake chamber. This burner will easily match the Micromongo burner, 3/4" burner tube, in its output. It is very impressive, especially its flawlessly smooth operating range of zero psi to 30 psi plus. My test jig gages would not allow me to test it at pressures exceeding this level. As Michael mentioned to me, in the upper pressure range you can actually feel the air suction with your hand at a distance of 8" from the burner! The ventouri vacuum is very impressive. [Image] My Personal Observations: I have finally had the opportunity to try out one of the Micromongo burners in a short but interesting test. It is a resonably good burner. I experimented with the nozzle flare adjustment to achieve the lowest input pressure, while maintaining a stable flame, and the results were better than I had hoped. With only 3/4" of flare exposure, the burner was stable to pressures down to 1 psi, or even a little lower. I did not have my most accurate gage on the system, so I am not sure exactly how low it went, but the gage needle was almost riding on the peg. This was after only about 15 minutes of experimentation. There is a very critical interaction between the jet location, centering, and the flare location, and the jet tube was loose in the mounting so I was unable to perfect the adjustment to its finest degree. I think that it is entirely possible to get this burner to operate in a stable manor at gas pressures down into the ounces range. Its upper end range is a given, but the low end capability makes it a very special burner indeed. This low end operation range is of no consequence when the burner is used in a melting furnace, but in a forge the low end ability will be extremely useful for some operations. It is possible that when I switch the present jet to one that is larger it will change this low end performance. That is yet to be determined. Parts breakdown image for the Micromongo (Before condsidering the construction of any of the Mongo series of burners, please read the informationa about the Side-arm burners at the top of this section.) ------------------------------------------------------------------------ *** Rules Of Thumb for Forge Design *** (For the 3/4" diameter Reil or EZ burners only) *Do not use these rules for the Mongo series of burners* [Image] If you want to design your own gas forge there are a few simple "rules of thumb" to keep in mind. These are not exact, and may not even result in a successful forge, but they are a starting place for designing your own propane forge system. There are a great many variables involved with any forge system, insulation "R" value, exhaust opening area, smoothness of burner penetrations, elevation, quality of forge and burner construction, jet diameter, tuning, etc., to name but a few. Any one of them can cause problems. To design forges using other burner types, use the BTU Calculator, along with the information in paragraph #1 below.** 1. You will need at least 450 BTUs per cubic inch of forge chamber volume if your forge is going to be able to forge-weld. Some would argue for a figure as high as 540 BTUs per cubic inch. 2. The "Reil Burner" will deliver about 135,000 BTUs at medium to higher gas pressures, and can be cranked up to almost 200,000 BTUs by raising the pressure to 20 psi or more. In the lower pressure range of from 1-6 psi, where I do most of my work, it will produce about 60,000 BTUs, or even a little less. Use the middle figure in any design calculations. 3. Shoot for a burner to volume ratio of 1:300 or less. Some smiths who are very knowledgeable would say a more conservative ratio of 1:250 would be safer and insure that your forge will be able to weld. To calculate how many 3/4" burners you will need just divide the total chamber volume of your forge, in cubic inches, by 250 or 300, and then round up. If you come out to a burner requirement of 2-1/3 burners, then you will need 3 burners for your planned forge volume. Always plan conservatively or you may end up with a forge that is too cold to forge-weld.** [Image] It should be apparent that a 4' long by 2' diameter pipe forge will require far too many 3/4" burners to be practical. Keep your forge chamber as small as possible. If you can't build what you need with these burners you may need to look at the "Monster-Burner" as a possible alternative to heat your forge. I will not provide rules of thumb for them, so please don't ask. You can easily enough get a "propane jet diameter/BTU output table" and figure this information out yourself. These tables are available locally through your propane dealer or on the Net. ** The above information is assuming that you will build a well insulated forge, having at least 2" of Kaowool lining coated with ITC-100, not Satinite, on the interior surface of the chamber. A 3" lining of Kaowool would be even better, and would probably pay for itself in fuel savings over the long run. If you elect to use a rammable or pourable refractory, or bricks, you will have to address the lower insulation values associated with these materials. One option is a composite design, a pourable refractory shell for durability, inside a Kaowool shell for insulation value. These are more difficult to build but are long lasting and can work very well. ------------------------------------------------------------------------ Materials and Hardware Sources Refractories, Burner Flares, & T-Rex Burners Sources For Refractory Materials [Image] A Word to Potential Advertisers: I do not carry banners, flashing icons, or other eye catching low class graphics to advertise products on my pages. All commercial links posted here are on my page for the convenience of the persons using my page, not for economic gain of the business or me. I receive no payment for any links or comments made here. My comments are honest evaluations of the source to make decision making easier for my page users. If you wish to add your link to my "Sources" section, it must be in keeping with the purpose of this section, and if accepted, it will not have any logos, banners, or icons, other than those already present in this section. If you would like to discuss a link please e-mail me. Warning, I receive many requests, but accept very few. [Image] I get many e-mails asking where to obtain the Kaowool, ITC-100, propane regulators, and other materials necessary in forge construction. Here are some sources for these materials, and others, that you may use to obtain needed parts and materials. Jay Hayes and Rex Price have refractory materials available at a very good prices, and much lower than available in most places. Jay has a web page which is under construction that you may wish to visit too, and is worth your time to do so, as he has a lovely place. Rex Price also produces and sells the finest and hottest ventouri burners made in the world at this time. You may want to visit Rex's web page and look at his burner selection instead of building your own. These are hotter then anything you can build on your own. Thanks. [Image] Here is another location that you may use, but you will have to phone this company at your own expense. This is "The Potter's Center" here in Boise, where I purchase my supplies when I need them immediately. They have Kaowool board, high alumina kiln shelves in various dimensions shapes and thicknesses, ITC-100, kiln shelf posts, and many other useful materials and items, including pyrometers. They will be glad to mail an order to you, but they do not have a catalog. You will have to work out your order over the phone. Their prices are high for some items and very reasonable for others. Phone (208) 378-1112, or Fax (208) 378-8881. Scott Brown, the owner, also has the following 800 number on his card, but I don't know that it is still in service, try 1-800-498-1126. [Image] I have to thank Matt Bomba for this link. Clayartcenter.com is a one stop pottery supply center, and has a good selection of all the needed components, refractories, and other items that you might need to build your melting furnace, forge, kiln, or heat treating oven. Their prices seem to be in line with the going rates elsewhere. Their online catalog is a little difficult to find, but if you go to the lower left corner of the page there is a box with links to various items. If you click on any of the items listed, you will be taken to the catalog and can easily explore from there. Check it out. [Image] Here is one more useful link. If you are involved with foundry work, this is a must have link. It is also of value for blacksmiths, or anyone who uses high temperature products. They carry refractory products, ITC-100 in its various forms, and a lot more. Budget Casting Supply is well worth a look. You can e-mail Paul if you have a question about a product too. [Image] I have no other sources than those listed above, so please don't e-mail me with a request for additional sources. I suggest you check locally in your area if the above sources are not convenient for you. [Image] A Note About ITC-100 and Kaowool: ITC-100 is more than just a ceramic wool stabilizer. It is an infrared reflector that reradiates up to 98% of the heat that strikes it back into the forge chamber. This will heat your iron faster, and will act like an additional inch of Kaowool, providing lower shell temperature and better fuel economy, as much as 30% better in independent tests. It will also stabilize the Kaowool so that you don't have dangerous ceramic fibers in the forge exhaust. It will last almost forever if it is not damaged through mechanical injury by you or others using your forge. Even though it is semi expensive, it is well worth the cost as it will repay you in various ways, directly and indirectly, very quickly. It may be used on any kind of forge chamber surface, not just Kaowool. Also, if you have metal surfaces in the forge, there are special undercoatings available to bond the ITC-100 to the smooth metallic surface. I should add that this material is not useful in a coal forge. [Image] Kaowool comes in two temperature ranges. One is about 2300 degrees, and the other 2700 degrees. Although your forge should run up near 2700 degrees, or hotter, you may use the lower temperature Kaowool if its fully coated with ITC-100. The ITC-100 should reflect the heat enough to prevent problems due to the lower temperature range of the material. I would suggest you use the higher range Kaowool however, unless you are unable to obtain it from your supplier. Jay Hayes has both available, so specify which kind you want when ordering. The higher temperature Kaowool is more expensive as would be expected. You should use ITC-100 on the Kaowool whichever kind you use. ------------------------------------------------------------------------ Do You Need a Premade Burner Flare? [Image] The following four factors are, in my opinion, what a flared nozzle does to contribute to burner performance, and why you should use one of your own making, or one of the stainless flares offered here. 1) The flared nozzle acts like the "impedance matching device" found on radio transmission antennas. It creates a "pressure transition" to balance the internal pressure of the burner tube to the lower pressure of the forge chamber atmosphere. 2) It slows the gas stream to a velocity below the burn velocity...its flame holding and stabilizing function. 3) It creates a low pressure in the nozzle step that, in effect, invites more gas down the burner tube, allowing a slightly greater output than would occur without it. This factor is not proven or provable with our crude testing equipment, but I can clearly see its contribution in my mind. 4) The last function is to initiate the burn earlier so as to prevent the injection of cold gasses and free oxygen into the chamber of the forge or furnace....the result is a hotter chamber and less, or no, scaling. [Image] If you would like to buy premade burner flares that have a perfect 1:12 taper, and made of stainless steel no less, there is now a source. Most of the problems that I deal with when helping guys with burner problems relate to the rate of flare of the burner flares that they put on their burners. If the flare is not made correctly the burner will not function correctly. I was astounded when Larry Zoeller sent me one of his "press formed" stainless steel flares to try. I removed one of the old forged flares from the number one burner on my four burner forge and installed Larry's stainless flare. My old mild steel flare came off in fragments, as it had totally corroded through in only two years of use. The best I had been able to do for "idle" pressure with my old forged flare was 2 psi. Below that the flame would start to pulsate or huff. When I put Larry's flare on the burner it easily held the flame steady all the way down to a little below 1 psi! His flare just doubled the "idle" economy of my forge! I have ordered 7 more from Larry, they are that good. I can certainly make my own flares, but to obtain the precision that Larry has achieved I would have to set up a hydraulic press as he has done. [Image] If you would like to obtain some of these superb flares, contact Larry at the address shown below, or at his e-mail address. I am sure you will be very satisfied with the results of your purchase. You may initially think that his price of $6.50, plus shipping, for a burner flare is steep, but remember that he not only makes them from stainless steel, but they are drilled and tapped, and come with two stainless set screws installed also. They are ready to just tighten into place on your burner. BTW, I get no payment of any kind for this "add." I just think that these flares meet a big need out there in the metalworking field and should be made available to the forge and foundry community. Please be aware that these flares can melt and deform if used on the Micromongo Burner when its run at high gas pressures. In the case cited in the linked document, Fred was running them at 25 psi. Larry Zoeller 4312 Lahnna Dr. Louisville, KY 40216 USA (502) 361-0706 zman59@earthlink.net Larry's Home Page [Image] Visit Larry's Burner Flare Page. You can see what they look like, and Larry has a price sheet with details there as well. ------------------------------------------------------------------------ Premade Burners Are Now Available The "T-Rex" Family of Burners [Image] [Image] There is now a superb new premade burner series available for those who do not want to build their own, or for those who want the ultimate in both quality and BTU output. The T-Rex is a turned, milled, and tuned hybrid designed jet ejector burner which has to be experienced to be believed. For a complete description see the "T-Rex Burner" page. [Image] [Image] Another burner that you may want to consider, and part of the developing T-Rex family of burners, is the "Shorty Burner." This is a miniturized T-Rex, and has applications in places where the T-Rex may not fit, or where this reduced sized burner would be more convenient. I have a Shorty Burner Page available if you would like more information. [Image] You may go directly to Rex's own Burner page if you wish. He has a troubleshooting page, and a price sheet there, as well as a short description of the burners he presently is producing, which now include several much larger burners than I have listed here. I will not keep his full listing of burners updated on this page now that he has this information available for you on his page. The descriptions for the T-Rex and Shorty burner I have here are more complete than what you will find on Rex's site, so you may want to read these first, and then link to his site. I have links to his site at the end of each of the above linked pages for your convenience. ------------------------------------------------------------------------ BTU Output Calculator [Image] I am very pleased to be able to offer you a very convenient BTU output calculator. It will allow you to calculate as closely as possible how much heat energy you are delivering out the nozzle of your burner, given the gas pressure you are using, and orifice, jet, diameter of the burner. This very fine program was created by Thomas Vincent. It is in Exel format, so you will have to have Microsoft Excel on your computer to be able to use this program. I have it available here in several forms. You may download the zipped file, which includes the "Orifice Document", the "Calculator Instruction Document", and the "BTU Calculator" program. You can then unzip it and use it as needed. Or, you can use it directly by simply clicking on the "BTU Output Calculator" file link. Again, to use this calculator your system will have to have Microsoft Office installed on it in order to be able to open these Word and Excel documents. If you download the files to use on your own system, be sure you read the instruction file first in order to prevent damage to the Calculator file through improper number input. The Calculator program requires entry of your burner "orifice" diameter in decimal form. I have the conversions from drill # to decimal diameter available in my FAQ. You are free to distribute this calculator file so long as you maintain the source information, my site, with the file and leave the authors name on all documants as they are provided to you here. Tom did a lot of work to provide you with this valuable tool, free of charge, so he deserves to be given credit for his work. Thanks. [Image] BTW, I am able to open these files with Office 97, so if you have Office 97, or above, you should be able to use this program without any problem. Due to the size of the Orifice document, it is advised that you download the zipped file instead of using these files directly off my site. BTU Output Calculator Orifice Coefficient Document BTU Calculator Instructions Document Download All Three Documents in Zipped Format ------------------------------------------------------------------------ Will Gas Forges Weld?....an E-mail [Image] I have run into two areas of ignorance that I have continually to fight, even on "theforge". One concerns the ability of a gas forge to forge weld. This is certainly not a problem within the members of theforge, but the second is. I was told by a smith on theforge that "everyone knows that gas forges can weld, and have for years", and that certainly is not true. I have posted an e-mail I received that addresses both of these points. I am posting this to show that there is still a lot of ignorance out there that needs to be addressed. We, as brothers in this craft, all need to tend to these issues when the opportunity is presented. Most certainly the gentleman who sent me the e-mail is not one who needs educating. He is anything but ignorant in these matters. I am posting his e-mail for your interest. He was kind enough to give permission for me to post this communication. Thank you Adam. ------------------------------------------------------------------------ How Hot Can These Burners Get? [Image] I am very pleased to be able to include information about Dave Moore's ultra hot propane fired crucible melting furnace. Dave has been very generous with his time and provided me with detailed information about his melting furnace. This is such a remarkable achievement that I felt it deserved its own page. Please click the image to learn more about this exceptional piece of work. (Note: Dave is normally very safety minded. Please do not ever pour hot metal without wearing proper personal safety equipment. As one person commented, one wandering spider in the mold and you will be wearing the liquid metal, and probably lose your eyes as well. Also, never pour metal while working over concrete. Spilled metal can cause the concrete to explode and blast you with molten metal, or burn down your shop.) [Image] Click image to visit page. ------------------------------------------------------------------------ Burner Chokes [Image] I am adding this short paragraph at the top of this section because I consider it of great importance. In our development of the Mongo series of burners we discovered the full potential of a choke. It will enable you to run the "Reil" burner, or any of the Mongo series, or Side-arm burners, down to levels of gas pressure measured in only a few ounces. The key is to have a choke that can totally close the intake bell, or holes. That way you can balance the air intake to gas injection no matter how small the amount of gas entering the burner. I can now easily run my Micromongo down until the gas pressure gage needle is resting on the peg, and the burner still has a stable flame, no huffing or other problems. I estimate I am running at 1-2 ounces of gas pressure at this point! So to achieve the very useful low end range, that all of these burners can reach, use a well designed and constructed choke. (Remember, for a choke to be of any value, your burner must be capable of running in an oxidizing state, oxygen rich, when running at full pressure.) [Image] I was not interested in burner chokes when I first built my big gas forge because I operated it at higher pressures than I presently find necessary. As I reduced my operating pressures down to the 1-1/2 to 5 psi range I found that more scale formation was occurring on my work. The answer to this problem is a burner choke. It allows you to tune your burner to a neutral or reducing flame at any given operating pressure. [Image] The following four choke designs are scanned from a small forge building publication that has no author or publication information whatsoever. The only clue to the author's identity is on the front cover which is simply "JF", with a "98" under the letters. I could not contact the author to obtain permission, but was informed by the person who gave me the booklet that it was free for duplication and distribution, so I can only assume that this use of its information would fall within those boundaries. If anyone knows the author I would very much appreciate information as to how to contact him to obtain his permission formally. Thank you. [Image] To use these choke designs it will be necessary to build your burner using the "Bordeaux Modification" so that you will have use of the threads in the throat of the burner bell, or the top surface of the bell. I would also strongly suggest that you use a 1-1/2" by 3/4" reducer bell instead of the 1-1/4" by 3/4" reducer when using a nipple section. This is due to the reduction in open intake area that installation of a nipple section will cause. I would also suggest removing any fins or flange that may be found on the interior lip of the nipple section used. It is important to maintain maximum gas flow through the system so that you can still operate at higher pressures efficiently, therefore choke design #4 may not be a good choice due to the considerable intake restriction it imposes on the system. Choke Design #1 Choke Design #2 Choke Design #3 Choke Design #4 The Best (?) Burner Choke Alternative [Image] An alternative that is worth considering is to lock your burner jet tube down by screwing a short length, say 1-1/4", of nipple into the mouth of the burner bell far enough to contact and lock the jet tube. You will have to use a bell diameter no smaller than 1-1/2" to do this however to maintain enough intake opening area. (You may even need to use a 1-3/4" bell if you find that the back pressure of your forge design causes your burner to run too rich.) I recently built a burner this way for a forge I sold and it worked extremely well. This makes the construction of the burner much easier because there is no drilling and tapping, and it also sets up the burner with a short nipple in the bell to which you can add an axial choke, see below, quite easily. [Image] One suggestion would be to attach a small diameter cross bar across the throat of the nipple, and to it weld or braze a short length of all-thread which would stick out of the center of the opening of the burner an inch or two. You could then weld or braze a nut to a disk of steel that would screw down the all-thread and act as a finely tunable choke. The disk would not have to be as big in diameter as the nipple, as it only needs to restrict the air flow, not stop it completely. By drilling a hole through both sides of the nipple just below the lip it would be an easy matter to insert a cross bar that closely fits the holes, and to which you had already brazed on the all-thread to form a "T". You could then align the all-thread to the center line of the nipple and braze each end of the cross bar into place. It would be rock solid and aligned almost perfectly. [Image] When I built the burner I cut the section of nipple off at a point leaving about 1/4" to 3/8" of unthreaded section of pipe above the ends of the threads. This is where the cross bar would go. You would do well to try to align the cross bar with the jet tube below it too for better air flow characteristics. If you drill the two holes in the nipple first thing they can be used to place a rod through the nipple allowing you to screw the nipple in very tightly without having to use a pipe wrench which will damage the surface of the nipple. You may want to drill two sets of holes, one set below the other, so that you will have these "wrench" holes available all the time. I elected to use one set of hole for both purposes. [Image] Please have a look at the image of my axial choke. It is currently mounted on my number one burner which has been modified to the Bordeaux mounting system. I cut two pieces of 1/4" all-thread and brazed them together in the form of a "T". The top of the "T" can be inserted in the two holes in the top of the nipple and locked in place with a nut on one side and wing-nut on the other. I need to be able to remove the choke when I cover the forge up at night or the axial rod will poke a hole through my tarp. Just use two nuts if you don't have to cover the forge. I used a large diameter 1/4" washer for the choke disk, and brazed a quarter inch nut in its center to allow it to be screwed down on the vertical stem of the choke's axial rod. It is easily adjusted while the burner is running because it doesn't get hot. It isn't necessary to have a disk as large as the opening in the bell. You only need to reduce the air flow, not stop it. Notice that I am using the holes in the nipple both to tighten the nipple on the jet pipe and to mount the choke. I love it when things serve for more than one function. :-) Here is another image taken after I converted my #2 burner over to the axial choke design also. [Image] I now have made some rather important discoveries about chokes that I explained at the top of the Choke section. If you build an axial choke, as shown in my images, I have two suggestions for improvements you may want to follow. First, increase the size of the choke disk so it can fully close the bell. The second suggestion is not of great importance, but is a matter of convenience. Instead of using a nut to braze to the disk, use a wing-nut. That way when you screw the disk down very close to the bell to run your burners at very low levels, it will be easier to move it up again by use of the wings on the nut. ------------------------------------------------------------------------ Additional Burner Designs Note: These burners are designed by others, so if you decide to build one, please contact the designer if you encounter problems. I do not support or guarantee in any way that these burners will function as stated below. I have NO experience with any of them. My comments are based entirely on what the designer has related to me and I have put into my own words. Thank you. "Monster Burner" and Melting Furnace (This burner easily melts cast iron!) Designed by Rupert Wenig, and submitted by Robert Grauman. [Image] This is a corker of a burner that has been perfected by Rupert Wenig. It is an enlarged version of my 'Reil Burner," but Rupert deserves all the credit for this one since I never dreamed that the burner design I posted could ever melt cast iron if scaled up. These guys up in Alberta enlarged the burner and then used it in a melting furnace built to the Gingery design. It easily melted 17 pounds of cast iron! The following images show the burner, the furnace, and the results of their cast iron melt. The burner also was used to melt aluminum, 2 kg in 10 minutes, and brass, 6 kg in 19 minutes, ... very impressive times. The cast iron took a little longer. The top link is the burner design drawing of the "Monster Burner" by Rupert Wenig. I should add that the "Tee" pipe coming off the side of the burner tube in the images is just a support handle to mount it in the furnace. If you are considering this burner, be sure to look at the Minimongo Burner too before making a final decision as to what burner to use. Foundry Melt Logs Burner Design Schematic Image of three burners Gingery Furnace Hot Interior of Furnace Pattern and Finished Cast Iron Casting ****************** Bienstock Burner Designed by Marshall Bienstock, photo by Bruce Freeman [Image] Click Image for Enlargement [Image] The "Bienstock Burner" design above is a more sophisticated version of the basic propane burner that allows greater control of the forge atmosphere. It is more complicated to build, and also adds to the burner length considerably, which will preclude its use in compact situations. If you have the room, and want to spend the extra effort, this is an excellent burner. ***************** Jay's Burner Designed by Jay Hayes, photo by Ralph Kessler [Image] Jay's Burner, Click Image for Parts Breakdown ******************** The John Wasser Modification [Image] John Wasser has created a burner construction web page for his modification to my basic design. His modification greatly simplifies the construction of the burner since no drilling and tapping is necessary. He has included bills of materials, and even a table of usable jet sizes and their conversions. Check it out if you want to build a burner quickly and easily. ------------------------------------------------------------------------ Hot News...ITC-100 Needs Recoating Periodically [Image] I partially rebuilt the chamber in my four burner forge today, Sunday, 3 Nov 02, and had a very surprising result. The front half of the chamber was showing all the use and abuse it had received over the last 5 years, so today I decided to replace the front end firebricks, and recoat the front half of the forge chamber, and the new firebricks, with ITC-100. I recoated only the front half due to its constant use. When I finished I allowed the ITC-100 to dry. I then lit the forge and allowed it to run at idle, only a couple ounces of gas pressure, to cure the ITC-100. I was surprised when I looked over after only a few minutes and saw the mouth of the forge chamber glowing a bright orange, and at only idle pressure. When I went over to look, there was a very definite line where the new ITC-100 ended and the old was exposed. I brought the pressure up to working pressure, 3 psi, and allowed it to continue coming up to heat for about 5 minutes. At that point the entire front half of the chamber was bright yellow-white, while the old ITC-100 on the exposed back half, that was in front of the movable back wall, was still dead black, no heat showing in the floor tile at all! There was also a very definite line on the coated Kaowool chamber walls, where the old and new ITC-100 met. [Image] This was a big shock to me. I didn't know that ITC-100 had such a definite life span. At this writing I do not know what the useful life span of ITC-100 is, but I hope to find out soon. Also, I do not know what signs indicate that the ITC coating has lost its usefulness. The coating in my forge had become very dark, even black on the floor of the forge. I only want to alert the metalworking community that ITC-100 needs to be recoated occasionally. How often still remains to be determined. I have been having some problems with my forge welding, but chalked it up to sloppy technique. Now I believe that I was not getting the temperature that I was previously when forge welding was extremely easy. I will post more info as soon as I learn more. The moral...recoat occasionally when your ITC becomes greatly discolored. You may easily apply a little test dab of ITC-100 in your forge and see if that spot becomes significantly hotter than the rest of the surface. If it does, you probably need to recoat. [Image] Here is the straight skinny, right from the source. This comes from Jock Dempsey, and is self explainatory. I am quoting his e-mail with his permission. His help is much appreciated. Ron, I have just spoken with Mr. Feriz Delkic, the owner of ITC, about your questions. He says that at forge temperatures there is absolutely no breakdown of the ITC-100. They have furnaces with oxidizing atmospheres in service for some 20 years without degradation of the coating. In all probability the problem is soot, scale dust, and other debris that has attached to the surface. Mr. Delkic says with a light coating of debris the ITC-100 is still acting as an isolator and reflecting the infrared, but that the debris is filtering it. In a small forge or furnace this might effect the recovery time somewhat. Predicting when this problem will occur would be impossible due to the many variables of individual forge usage. I would expect it has as much to do with how many times the forge is fired, and how long it is run each time. Commercial usage forges may run non-stop for weeks, or at the least for a full 8 hours. In your shop and mine we may run the forge for an hour or two, shut it down, and run it for another hour later in the day. When I am casting with my little melting furnace, I run it for half an hour, shut down when I pour, and then fire back up for the next melt, maybe 5 or 10 times in a day. I would guess that if soot is the problem, then the number of cold restarts is a factor. Forges are also exposed to scale and scale dust. Fine scale dust blows around in the forge, and the surface temperatures are high enough for it to melt and stick to those surfaces. As you know the ferric oxide can damage some refractories, such as the alumina in Kaowool. It does not damage the ITC-100, but it does cling to the surface. Again, this is not a failure of the ITC-100, but an operating condition particular to forges. Kilns and other types of furnaces each have their own pecularities. I would say that recoating the forge with a thin wash at least once a year would be good practice. I have found that once a surface is coated that it takes very little to recoat it by brush application. Spraying may take more, as the consistancy must be just right to stick and not run. Jock ------------------------------------------------------------------------ Some Gas Forge Designs My Four Burner Forge [Image] The four burner forge I built, using the burners I discussed above, has turned out to be an excellent forge in every respect. It was built using a custom rolled cylinder of 11 gage steel, lined with two 1" layers of "Kaowool." It is coated with "ITC-100", manufactured by "International Technical Ceramics Corporation". The cylinder is 24" long by 12" in diameter. I will not provide any diagrams here as the images and narrative are enough to allow anyone with basic metal working skills to duplicate it, or a modified version. [Image] I used 2" of "Kaowool" liner, but perhaps 3" would be a good additional insurance if you are at higher elevations where forge performance might be marginal in achieving welding temperatures. I highly recommend "ITC-100" over the use of "Satinite" It is a superior IR reflector, reflecting back up to 98% of the heat that strikes it. This contributes to lower forge shell temperatures, higher interior temperatures, as well as fuel savings. [Image] The floor of my forge is rather special in design. I wanted to preserve as much insulation as possible so designed the floor to sit above an inch of kaowool at the extreme edges, and almost two inches in the bottom center. I used one half of a 12"x 24"x 1" high alumina kiln shelf. The 6" wide kiln shelf floor sits on six 1" high kiln shelf posts that are kept in place by 3/4"x 3/8" diameter rods blind welded into holes in the bottom of the shell. This prevents the weight of the floor plate from compressing the kaowool, and provides the necessary space to allow one full wrap of kaowool around the circumference of the forge shell. The second layer runs from one edge of the floor plate around to the other. I also added another strip of kaowool under the plate to fill up the gap in the center. Once all was in place, everything, including the floor, was coated with "ITC-100". When I eventually rework the interior of my forge I will make one modification. To protect the fragile Kaowool walls I will install two full length, by 2" wide, sections of kiln shelf on either side of the floor to act as bumper strips. They will be angled outward and blend in with the surface and curvature of the Kaowool liner. By doing this the forge will be much more resistant to mechanical damage in its interior. [Image] I wanted to be able to easily change the opening to the forge to suit the work at hand. Although my "brick wall" may not be as pretty as some other arrangements, it has great versatility in allowing any configuration needed to be instantly arranged. I constructed a "brick shelf" that is part of the forge for the bricks to sit on. All bricks are coated with ITC-100 also. The bricks are not standard fire bricks, but are ultra light weight high temperature kiln bricks. They run from $3.50-$4.00 US per brick, but their high thermal efficiency justifies the expense. Odd as it may seem, the less expensive bricks, $3.50, are actually better than the higher density and higher priced bricks because of their better insulation qualities. [Image] If you are new to forge work, and especially to ceramic fiber insulation, you need to be aware that welding flux, such as borax, will eat through them as fast as water through cotton candy. That is one reason for the heavy kiln shelf floor plate. I also recommend you consider a piece of stainless plate, or sacrifical piece of kiln shelf, placed under your fluxed iron to protect the forge floor, since it will attack that as well. [Image] The burner mounting on my forge was done using threaded pipe sections that screw into pipe couplings that I sawed in half and welded to the shell. The pipe sections were big enough to allow free passage of the burner nozzle through into the forge chamber. The nozzle is held in position by two rings of three "set screws", in this case 1/4" diameter bolts. This allows me considerable adjustability on my burner positioning and aim. I don't believe in the commonly held belief that the burners should be mounted at a tangent to create a vortex in the forge. My experience indicates that it is not necessary, and may in-fact contribute to scaling. I have mine aimed to the side of the floor plate, but not on the wall of the chamber. I can adjust them to dead center if desired, or to a considerable angle to produce a vortex. [Image] The penetration of the burner nozzle goes only as far as the interior surface of the outside layer of kaowool. The interior layer of kaowool has a hole poked through it with a conical punch to continue the path to the interior of the forge. This allows the burner nozzles to be out of the extreme heat of the forge preventing any damage to them. The kaowool seals quite effectively around the burner nozzle preventing any blow-by from coming up between the burner tube and the mounting tube holding the burner. [Image] There are two improvements I have incorporated into this forge that are not normally found on gas forges. I use a movable back wall inside the forge to reduce the forge chamber dimensions to the minimum necessary for a particular application. If the work is small, and I only need one burner, the wall can be slid all the way up to create a very small, but very efficient chamber. The movable back wall is made of a piece of "kaowool board" cut out to allow clearance around it for gas escape. It is also coated with "ITC-100" to further increase its efficiency as an IR reflector. This cuts down on heating unused space and increases fuel efficiency. Note: Please visit my Forge Page for an important update to this movable back wall design. Look under "My Newest Forge Design", at the bottom under "Update". [Image] The second big improvement I incorporated into my forge concerns the plumbing for the four burners. I used individual ball valves for each burner. This allows me to use only the number of burners necessary for the work at hand. The second modification is the use of two valves on the gas inlet line. They are configured in a parallel arrangement with one of them a normal ball valve (on/off), and the other a needle valve to allow precise control of a small gas flow to the burner. With this arrangement I can adjust the input gas pressure to whatever working pressure I need using the regulator, and then with the "on/off? valve to the "off" position, adjust the needle valve for a minimum burn level, an idle flow rate. [Image] With this arrangement I can instantly shut the forge down to a minimum burn rate while I am at the anvil, and when I return to the forge can instantly return to my full working pressure with just a flip of the "on/off" valve. Since I sometimes spend extended periods at the anvil this results in considerable gas savings. To shut off the forge I use the individual burner valve(s). It took me a day to get used to flipping the valve on and off each time I went to the anvil, but quickly became an automatic response for me. I highly recommend this modification. (For more complete information on the idle/full valve arrangement, including images, consult the Four Burner Forge Design description on my Forge and Foundry Page.) [Image] I used all brass valves and plumbing on my forge, but iron will do as well, and at much lower cost. I also have a quick disconnect on the forge so that I can easily disconnect the propane tank. This is a very useful addition. [Image] I will conclude with a few comments on the operation of my forge. Any burners that are being used will remain very cool to the touch while in use. They will heat up once the forge is shut down however, so watch what you touch. The burners that are not being used provide an open chimney to the forge, and the ultra hot gasses will pass right out through them heating them to dangerous temperatures. To prevent this I simply stuff a small wad of paper towel into the throat of each unused burner. When I wish to add a burner, even when the forge is running, I simply use a pair of needle nose pliers to pull the plug out, and then switch on the gas valve. The paper will not burn while in the burner tube. [Image] Some smiths like the thermal mass of a poured in place refractory lining in their forges. There are both advantages and disadvantages in such linings. In my case, I like to have my forge cool down as quickly as possible when I shut down since I use it outside and need to cover it. Poured in place linings take a very long time to cool. The poured in place lining, let's call it "rigid lining", is far more forgiving of the abuse that careless handling of the iron can cause. On the other hand it is far less thermally efficient as an insulator. This may mean the difference in achieving, or not achieving, welding temperatures at higher elevations, and in some case lower ones as well. If you will want to move your forge, the ceramic wool liner will certainly be superior for your needs. [Image] If you are not familiar with the products I have discussed here, and their sources, try calling your local pottery supply store. They cary kilns and supplies such as "Kaowool" and "ITC-100", as well as "Satinite". If they don't have them on hand they can order them for you. When you are there look around at the various types of refractory products they cary. You will be able to get your kiln shelf floor plate and support posts there as well. You may have to look around however to find a place that will sell small quantities in some cases. If you are unable to locate ITC-100, it is made by "International Technical Ceramics" which you should be able to locate on the internet, and contact to find a local source. Another version of the 4-burner forge, built by Gordon Kerr See Also the Construction of My Freon Tank Mini-forge ------------------------------------------------------------------------ Some Additional Gas Forge Designs Forge #1 Submitted by: Matthew Wills, design by Matt and others Image 1 , Image 2 Forge #2 Submitted by: Richard Sevigny Richard's tiny forge was inspired by Ed Halligan's design as posted by Donnie Fulwood! Image Forge #3 Submitted by: Harry Foster A very cute tiny forge. Image Forge #4 Submitted by: Larry Zoeller This is a micro forge that uses a propane torch for heat. Cute forge! Construction Plans & Images Forge #5 "Sandia Recuperative Forge Design" [Image] Note on an alternate Clamshell Forge design: The Sandia Forge is a very sophisticated forge design, requiring an extraordinary amount of labor to build. It is of particular value for wide flat forgings like scrolls. We are building some interesting forges that have a large flat floor, 18" x 24" or larger, and a flat top lid that is attached to a vertical lift system. The lift system can be as simple as a camper-jack. You can crank up the lid and stack a wall of fire bricks around the edge of the floor in whatever arrangement and height you require, then lower the lid to close it in. You can also lay a refractory rope on top of the bricks to get a tight seal. The burners can be top or bottom mounted, and the top can also have an additional treadle lift for instant opening. This allows total versatility to set up the forge for whatever the task at hand requires. This offers far greater versatility than the Sandia forge, and the work is only a fraction of that required to build the Sandia forge. Using high quality burners like the Rex series, an idle/full valve arrangement, and ITC-100 interior coating, it will almost certainly match, and probably exceed the Sandia in both operating temperature and fuel efficiency. I say "probably," because there are so many possible variations of this forge, and different insulating options, that you would have to compare specific forges for a definite answer. I have pictures of several of these completed forges that were built in Maine, but they are not mine to publish here at this time. I hope to publish images of my own version in the future. [Image] Submitted by: Chuck Kishaba This very fine forge is a recuperative propane forge built from the "Sandia National Labratory" plans which are available from ABANA. The images show various views of the finished forge, along with two images of it heating some 1" diameter bars. This is such a fine piece of work that I am going to quote Chuck's entire e-mail explaining the following images. His excellent description follows. Much thanks Chuck. Chuck' Description; Well, here they are. Let me give you some info on each JPEG photo. 1) forge5.JPG is a 3/4 front view of the forge 2) forge6.JPG is a 3/4 rear view of the forge 3) forge3.JPG is a front shot with the door open 4) forge11.JPG is a close up shot of the heated bars 5) forge8.JPG is a shot of a cold forge with the cold samples prior to light up 6) forge9.JPG is a shot of the bars being heated 7) forge10.JPG is a shot of the bars after 8 minutes from a cold start My story: I needed an economical means to flatten the ends of 1" diameter solid round bars. I looked into induction heaters (incredibly expensive) and commercial propane forges. I'm not a blacksmith and needed something that I could light up, do my work, and shut down. I liked the efficient design of the Sandia forge and decided to buy the plans from ABANA. The forge was not easy to make. It helps to have sheet metal skills and a lot of patience to fit the ceramic insulation board. It took me about 3 months working in my spare time. Description: Air enters 2 flattened stainless steel preheater tubes from the rear of the forge. This air then mixes with the propane, and the air/fuel mixture goes into a ventouri that necks down to the burner tubes. The exhaust gases exit the rear vertical chimney which pass around the 2 flattened stainless steel preheater tubes. This feature preheats the intake air to 1000F. The preheated air increases the velocity of the mixture and this results in a hotter forge, and a 25% savings in fuel. The white insulation covering the burner tubes is 1" kaowool wrapped in stainless steel wire screen. The main insulation is 1" thick 2600 ceramic insulation board. I obtained it from Thermal Ceramics. (http://www.thermalceramics.thomasregister.com/olc/thermalceramics/salloc.htm) I paid $26.00 per square foot for the board. Changes: The biggest change I made from the ABANA plans was the door. The original plans call for a door without the oval opening, only a notch in one corner. My door does lose some efficiency, but as you can see from the photos, works quite well for my purpose. The stand is also different from the ABANA plans but has no effect on performance. Performance: Photo (forge8.jpg) is a shot of a cold forge with five 1" solid round 1018 bars ready to be heated. Photo (forge9.jpg) is a shot of the forge 30 seconds after startup with the five bars inserted into the door. Photo (forge10.jpg) shows the five bars after 8 minutes. This is all from a cold start with the bars inserted immediately after startup! I've ran the forge for about 1-1/2 hours from a 30 lb propane tank with no freeze-up. I usually run about 5-7 psi of pressure. Conclusion: I am extremely pleased with the performance of this forge. It works better than I imagined and was worth the expense of the ceramic board and difficulty of construction. I would like to thank Robb Gunter, Karl Schuler, and Ronald Ward of Sandia National Labs for their excellent design. ABANA is on the web at: www. abana.org. To order the plans, go the the site and click on "ordering" On the ordering page you will find a listing for "recuperative forge plans". Good Luck! Chuck Kishaba Los Angeles CA tmcgroup@aol.com Forge #6 Building a Large Gas Forge By: Steve Smith [Image] This is a copy of a newsletter article that Steve Smith wrote, and has very generously allowed me to post to my site. It describes the construction of his large gas forge in detail. If you are considering building a forge you may want to read this document to get another description and viewpoint of building a large gas forge. Click the title to visit this page. Thank you. ------------------------------------------------------------------------ Links To Forge & Burner Designs, or Images Don Fogg, Bladesmith-Gas Forge and Burner David W. Wilson's Forge Design Page (Two designs) The Zowada Gas Forge System Walt Scrivens Freon Tank Forge "Tales of a New Blacksmith" by: Marc Godbout...must reading for the new smith. ------------------------------------------------------------------------ Coal Forge Designs [Image] There is now a counterpart to my gas forge site that is dedicated to coal forges, Forge and Fire. Matthew Rutz has done a superb job of posting a large body of coal forge information to his site. Be sure to explore all of his site, it is extensive and rich in content. [Image] I have already covered the construction of my big coal forge in some detail on my "Forge and Foundry Page", so I will refer you to that location. Forges for coal can be very simple, no more than an old barbecue fixed up with an air supply coming in from the bottom with a clay lining in the pan, to the very complex, and difficult to build, forge you will see on my page. I will post pictures of coal forges from other smiths as I come across them and feel they are particularly useful or clever in some way. [Image] BRAKE DRUM FORGE: You can quite easily build a very serviceable forge from a big cast iron truck brake drum. The hole is already provided in the bottom to bolt in your air grate, a piece of 1/4" steel plate with holes drilled in it. You only need to attach a plumbing "Tee" on the bottom to provide an inlet for your air, and also to be your ash dump. Put some legs on it, and a blower of some kind, and your in business. These forges do not even need to be lined with anything, and most of them have a fairly deep bowl giving you a good deep fire. Their only down side is that you will have a difficult time getting long stock into them for heats in the center area of the stock. A friend of mine, who is a very good smith, uses one of these forges and is able to make remarkable things with it. He cut out two slots, one on either side, and installed doors to allow long items to be heated. He also has a chimney installed to prevent breathing too much of the smoke.....a great idea. I hope to have a picture of his forge here soon. Robert Bordeaux has provided a unique design in which he uses the brake drum as the bottom fire-pot, and expands upward into a blower housing, creating a much larger pan. The forge is lined with a 1/2" thick layer of furnace cement. Robert deserves lots of thanks also for his contribution of the "Bordeaux modification" to the burner design I have posted above. It is a superb modification. [Image] NOTE: Coal smoke will do bad things to your lungs and body over time, so a chimney is very important on any coal forge, indoors or outdoors. [Image] FIRE-POT DESIGN: Bill Franchini has provided the following home built clinker breaker fire-pot design. It is straight forward, except that the drawing shows the use of a square section tuyere, instead of a 4" diameter pipe. He built it this way simply because he didn't have 4" pipe available. It should be easier to construct using the pipe.If I were building this fire-pot I would make the fire grate out of two separate pieces. One part would be a grill fabricated out of the materials shown in the drawing, with "fingers" for the grill elements, and the portion that is actually attached to the rotating handle would be another set of "fingers" that would pass between and through the grate fingers as it was rotated, thus reducing the loss of coal Bill mentions in his instructions document. Fire-pot Drawing Instructions Text ------------------------------------------------------------------------ Additional Coal Forge Designs and Misc Brake Drum Forge at Anvilfire.com Paul Stevens' Brake Drum Forge ------------------------------------------------------------------------ Blacksmithing Terminology [Image] Thanks to the efforts of Paul Stevens there is now a glossary of blacksmithing terms available for new folks to consult if needed. Check it out. :-) ------------------------------------------------------------------------ Page Count Since 19 June 01 [Image][Image][Image][Image][Image][Image] (This site had a count of over 144,450 before it was moved to this new location.) ------------------------------------------------------------------------ [Image] 20 Apr 03 Edited With AOLpress ©Golden Age Forge [Image]