TinMan57 Posted November 12, 2018 Share Posted November 12, 2018 I have a Johnson Gas Forge #133 at work and we have been trying to forge weld with it without any success. I called Johnson and they didn't really have any answers or tips of note. Does anyone in this community have experience getting a Johnson Forge hot enough to forge weld? It seems as if it's hot enough, but with the burner so far below the surface I don't think the steel is getting all the heat the forge is putting out. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted November 12, 2018 Share Posted November 12, 2018 Ar you running propane or natural gas? Are you keeping the lid down close? What temp does your thermocouple read? BTW: Those industrial type forges tend to be real gas hogs and it would probably save you a lot of money to build a welding forge more suited to the task. I know a smith who built a much larger forge that uses a ribbon burner and gets to welding temp at 7000' here in NM; I've had someone accidentally forge weld their 3/4" diameter rod to my 2.5" sq stock---had to use a sledge to separate them---no flux too! Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted November 12, 2018 Share Posted November 12, 2018 What are you trying to forge weld. The Johnson forge that was in the metal shop class at the high school (don't remember the number but it was a 4 burner) would weld without any problem but wrought iron took a lot longer to get to welding heat. Quote Link to comment Share on other sites More sharing options...
TinMan57 Posted November 12, 2018 Author Share Posted November 12, 2018 It's natural gas fed by a 1 ¼" line. The lid is all the way down, and with fire bricks in the back so the flame is all directed to the front. The gas doesn't cost our program anything where propane would have to come out of our budget. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted November 12, 2018 Share Posted November 12, 2018 Have you checked the manual? Quote Link to comment Share on other sites More sharing options...
TinMan57 Posted November 12, 2018 Author Share Posted November 12, 2018 Just now, Irondragon Forge & Clay said: What are you trying to forge weld. The Johnson forge that was in the metal shop class at the high school (don't remember the number but it was a 4 burner) would weld without any problem but wrought iron took a lot longer to get to welding heat. Really we're just going for proof of concept, ½" square stock usually. Eventually I want to make pattern Damascus tools. We are a community college and it's got 4 burner holes. Just now, Irondragon Forge & Clay said: Have you checked the manual? Yes, but it doesn't mention forge welding. . . Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted November 12, 2018 Share Posted November 12, 2018 Boy I don't know. I guess that all 4 burners are running and the orifices are clear of debris. Quote Link to comment Share on other sites More sharing options...
TinMan57 Posted November 12, 2018 Author Share Posted November 12, 2018 Yup, we got it brand new. I don't have any experience with them other than this one though. Is the an infrared thermometer that reads hot enough to diagnose the burner and forge heat? Quote Link to comment Share on other sites More sharing options...
Latticino Posted November 12, 2018 Share Posted November 12, 2018 Not at an approachable price. Have you ever forge welded in other forges? Are you using good procedures: metal with ground clean surfaces, close proximity, reducing atmosphere, starting to flux when metal just starts to show color, soaking at forge welding temperature for a couple of seconds before pulling the stock, not dawdling from the fire to the anvil, light tap to initially set your weld rather than beating on it...? If already doing all of the above, I would try welding with high carbon stock instead of mild first. It welds at a lower temperature and will at least give you a feel for the process. Quote Link to comment Share on other sites More sharing options...
TinMan57 Posted November 13, 2018 Author Share Posted November 13, 2018 14 hours ago, Latticino said: Not at an approachable price. Have you ever forge welded in other forges? Are you using good procedures: metal with ground clean surfaces, close proximity, reducing atmosphere, starting to flux when metal just starts to show color, soaking at forge welding temperature for a couple of seconds before pulling the stock, not dawdling from the fire to the anvil, light tap to initially set your weld rather than beating on it...? If already doing all of the above, I would try welding with high carbon stock instead of mild first. It welds at a lower temperature and will at least give you a feel for the process. Thank you for the reply. No I've never tried with another forge, although our procedures are good. I think the forge does get hot enough it's just that the flame is quite a bit below the stock. We've got some sucker rod that checks out similar to 4340 on a LIBs scanner and I can try it. If the infrared scanners are that much I think I may just try to get a Chile forge to weld with. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted November 13, 2018 Share Posted November 13, 2018 Flame being below the stock is GOOD You DON't want the flame playing on the stock as it is often oxidizing as it hasn't burned up all the O2 yet---that's why it is a "flame"! Quote Link to comment Share on other sites More sharing options...
TinMan57 Posted November 13, 2018 Author Share Posted November 13, 2018 4 minutes ago, ThomasPowers said: Flame being below the stock is GOOD You DON't want the flame playing on the stock as it is often oxidizing as it hasn't burned up all the O2 yet---that's why it is a "flame"! I get that you don't want the flame bathing on the stock, I just can't quite get the stock hot enough (yet) to forge weld. It's rated at 400,000 BTU's but they don't give a temp rating of stock or any suggestions on how to get it hotter. We've had success by putting bricks in the back and directing the heat to the open side. I'm really looking for anyone who may have had success with a natural gas Johnson Forge and forge welding. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted November 13, 2018 Share Posted November 13, 2018 I used to have some Johnson equipment but I moved where we don't have NG and feeding one on propane isn't economically feasible for me. So I traded off what I had for stuff I could use. (Including 5 gallons of Parks 50.) Bought it at the Columbus Public Schools Auction(s) for pennies on the dollar. Quote Link to comment Share on other sites More sharing options...
Latticino Posted November 13, 2018 Share Posted November 13, 2018 The NG Johnson forges are heavy, inefficient beasts that appear to be made for production or institutional uses. The last time I used one was over 30 years ago, but I don't remember it getting stock up to any kind of white hot temperatures (not that white hot is needed for forge welding, just that it can be easier as a novice to same). The reason I asked about proper setup and procedures is that while forge welding isn't as difficult as some make it out to be, there are some subtleties that can be missed if you are taking your direction from a book or YouTube. I've seen experienced forge welders make a joint in stock that I would swear wasn't nearly hot enough, and beginners miss a weld by either moving to slow or hitting too hard initially when the stock was throwing sparks as it was pulled out of the forge. It certainly isn't the natural gas. I have forge welded in my NG forge with a burner rated for only 150 MBH instead of the 400 MBH for the Johnson. Quote Link to comment Share on other sites More sharing options...
TinMan57 Posted November 14, 2018 Author Share Posted November 14, 2018 23 hours ago, Latticino said: The NG Johnson forges are heavy, inefficient beasts that appear to be made for production or institutional uses. The last time I used one was over 30 years ago, but I don't remember it getting stock up to any kind of white hot temperatures (not that white hot is needed for forge welding, just that it can be easier as a novice to same). The reason I asked about proper setup and procedures is that while forge welding isn't as difficult as some make it out to be, there are some subtleties that can be missed if you are taking your direction from a book or YouTube. I've seen experienced forge welders make a joint in stock that I would swear wasn't nearly hot enough, and beginners miss a weld by either moving to slow or hitting too hard initially when the stock was throwing sparks as it was pulled out of the forge. It certainly isn't the natural gas. I have forge welded in my NG forge with a burner rated for only 150 MBH instead of the 400 MBH for the Johnson. Thank you for the reply, which forge do you use? Quote Link to comment Share on other sites More sharing options...
Latticino Posted November 14, 2018 Share Posted November 14, 2018 My forge is a homebuilt one with 2" kaowool liner with a seal and topcoat of refractory and ITC. I do have an industrial burner assembly that I stole off my former glass furnace. Quote Link to comment Share on other sites More sharing options...
Frosty Posted November 15, 2018 Share Posted November 15, 2018 I picked up a Johnson Appliance #122A some years ago as part of a take it all or go away deal. The #133B is a double wide version otherwise they're about the same beast. Mine is lined with two layers of standard sized hard firebrick. It has a gun (blown) burner with 4 outlets just off the bottom of the chamber AKA trench. Were I going to need a trench forge, say I'd morphed into a commercial operation rather than a hobbyist I'd planned on relining it with Kaowool and a hard inner liner. It's sitting out back of the shop slowly sinking into the ground. I worked out of one one time and running full blast it got to high orange. Lifting the lid was torture, the IR was intense and the work was only high orange. It was running on NG, lots of NG. They're known for being fuel hogs and not really very hot. They're high production furnaces intended to bring lots of stock to high orange in a short time. Johnson Appliance supports all their products even the ones that've been out of production for many decade. They don't hard sell you on something new and I've never gotten an unsolicited Email. Converting to propane is as easy as changing the jet and if it's new enough it'll adjust itself to a neutral flame. Just remember at LEAST 4" of hard refractory liner fuel hog, forge. We had a 4 burner nozzle (outlet) Johnson pedestal, "box" forge in Jr. and High school shop classes. Powered by NG but more than hot enough to weld, it'd melt your stock if you weren't paying attention. I always loved the burner alignment, two horizontal just off the floor from the right side, the other two horizontal outlets just down from the ceiling on the left. It auto adjusted so nobody had to fool with tuning the flame. The flames from the outlets made it maybe 1/3 of the way across the chamber. I loved that forge, spoiled me completely. Unfortunately it was hard to get any shop teacher to light one up, Blacksmithing was NOT a promising career and we were there to learn marketable skills not hobbies. The last couple semesters on High school I took "Occupational Heavy metal" shop which started an hour earlier than regular classes and lasted 2 hours. My parents had the same attitude about blacksmithing, "Learn a paying trade," was a saying I got sick of hearing. Neither believed I'd want a hobby that was such hard work. It isn't so hard if you're not trying to make a living at it. Anyway, that's my story and I'm sticking to it. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted November 15, 2018 Share Posted November 15, 2018 Loved that story Quote Link to comment Share on other sites More sharing options...
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