New Majestic Forge - a couple of questions - Pictures.

[Col Defender]

Hi - Here's my newest knife making tool -





It just came yesterday and I tried it out just a bit, first by "heat treating" a small scrap of 1084 (which is the only steel I use so far) just to get an idea of how much flame to use without burning anything up and that worked fine. I also heated a blank just enough to soften it so I could use my name stamp and that worked too. The instructions that came with it were pretty good for assembling the forge but did not give me a lot of info on using it to heat treat.

My questions for any of you who use an Majestic Forge are several;

Should flames really be coming out of the openings as in my picture above?
What gas pressure should I use for this two burner forge on 1084? I used 5 PSI based on guess work.
Should the flame come all the way down from the mixing tube to the liner? Mine does not and if it did it would really be pouring out both openings.

Any other hints on how to use it will be most helpful...but I've already decided it is way better than the improvised forge I was trying to use before.

Thanks

Steve

 

[Col Defender]

Oops - may have just answered one of my own questions. Just saw that the instructions say the start up pressure should be 5 PSI per burner so I started it at 10 PSI and seemed to have much more manageable flames. But I still don't know if I should leave it at 10 or adjust to something else in actual heat treating.

 

[Stacy E. Apelt - Bladesmith]

The "Dragon's Breath is normal. Throttling back the gas pressure will reduce it if it is too excessive. Normally, you run a forge at the lowest pressure needed to get the steel to the desired temperature. Unless welding damascus, there is seldom a reason to run a forge wide open and have flames shooting out the ports like a jet engine. That just wastes propane and shortens the life of the forge.

The gas pressure for forging should be sufficient to bring the blade to a yellow heat ( but not sparking and burning) in a reasonable period of time. About 60 seconds or so for a small blade is right, and a few minutes for a big bar of steel. If the Dragon's breath is heavily yellow, or the burners are squealing, then the air choke or the venturi needs adjusting

On a venturi forge like yours, you may not be able to lower it to where HT is optimal, so when doing HT just turn down the pressure until it sputters, and then raise it a tad until it burns evenly and as low as possible. Test that gas setting on a bar of steel and see how evenly you can heat it and get it to non-magnetic. The perfect setting would allow you to heat the blade to just above non-magnetic and hold it there without it getting any hotter ( not likely to happen on that type forge). Most likely it will be much higher than the desired temperature.

Those "straight down from the top" style forges with big wide ports are fine for farrier/blacksmith work and basic blade forging, but they aren't very good for HT. What you have to do is throttle the gas to the lowest controllable pressure, and keep the blade moving and turning constantly. Move the blade in and out and from side to side while holding the tang end in the tongs. Try to always point the edge toward a wall or the floor. Avoid pointing the edge up into the flames. Place a welding magnet on the forge shell on the side and check the blade for non-magnetic as it heats. Once it gets to non-magnetic, heat evenly as possible and to a shade brighter red than it was at non-magnetic. That is about the austenitization point of most carbon steels... 1450-1500F.

A muffle pipe can help a bit. Put a heavy walled piece of 2" pipe centered in the forge. Let it heat up to fully red, and place the blade in the pipe. Use the big long needle nose pliers from Harbor Freight or a pair of thin jawed pick up tongs (the HF needle nose pliers set is very useful in the forge....get a set).
A 12" piece of schedule 80, 2" stainless pipe is a good forge accessory for doing HT. Regular pipe will work, but won't last as long.