Hello all. I am new to this forum, and came across this thread while searching for the answer to a question about forge welding temperature. I’m posting it here however as I have this same forge built from the same video. I’ve learned a lot reading the site so far and fiddling with the forge I’ve built to try to get things running properly and here’s my question. Is flux required to forge weld, does it actually lower the required welding temp (or have I read that wrong) and is mild steel harder to forge weld because of its lower carbon content? I believe I have the answers from reading other posts on this site but I have nobody to confer with in my area on the subject so I’m looking to confirm. (Not required to weld but highly recommended, it does lower the required temp, and mild steel harder to weld than higher carbon steels.)
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As for this forge build here is what I’ve learned so far with my version. The entire assembled burner I have is approximately 9 inches tall. The chokes are currently set at half open, with the pressure regulator on my propane tank set to 17-18 psi. Using the same parts list in the video posted above. I have found that a small 20lb propane tank is insufficient in being able to supply fuel fast enough. I experienced constant freeze up and a 40lb tank immersed in a small container of water performs much better even in cold temperatures. The lining is 2 inches of ceramic refractory fiber blanket that has been rigidized and coated in ITC-100. The floor is refractory cement (2300 degree rated if I recall). The top welds around the collar were a little sloppy so I have some of the ceramic blanket around them to seal any gaps. Where the burners are mounted with set screws, I found I MUST have that gap closed or the fuel/air mix would not stabilize. Once sealed it was a noticeable difference.
Currently running, the jets are approx the same size, stable with no sputtering and a consistent light-med blue (according to my eyes anyway). The DB starts out more blue with a hint of orange at the tip upon first start up but after approx 20 mins or so it is more orange throughout. I try to keep the front and back openings sealed as good as possible with firebrick while heating pieces.
I purchased a high temp thermometer that reads 2350 degrees F after 20-30 mins operating. I believe this is hot enough to achieve forge welding. I have flux ordered and will try again once it arrives, but having read several articles describing it being possible without flux I tried and failed. I believe I am making some sort of mistake at this point since the thermometer reads an adequate temp for welding (I think). Also, the pieces don’t appear to have excessive scale while in the forge but they do scale considerably upon removal which is why I believe I’ve failed at welding thus far. I have posted some pictures of the forge while building and will also post some video of the forge running and temp readings. I’m hoping they all work for everyone. Thanks for your time and I’m looking forward to hearing some feedback etc. I hope it may have helped with your questions HazenDart.
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