Vertical forge, how big is best?

[bobw]

I was chatting with Puzo the other day about making a forge for welding. I have a couple of old gas bottles that could be used. One is a 13kg the other about half that size, what do you think would be the best to use. I have a simple blown propane burner (Hair dryer/machine mart torch) that I think should be enough and Puzo is making a venturi burner to try as well. Planning to line the bottom with castable and the top with wool. It would be nice if we could use it to try casting a bit of bronze as well. If we used the small bottle the internal cavity would be something like a 12 inch by 8 inch diameter. Does this sound about right? I know the bigger it is the more heat we will have to put in, just wondering if you can go to small with these things.

Any advice appreciated

bob

[van Zanten]

what is the burner tube's size? Here are 4 video's about mines, it might give you some idea's. Good luck! http://www.youtube.com/user/zambiesz?feature=guide

[bobw]

Nice workshop! That forge looks impressive, I like the idea of it not having a bottom to get destroyed by flux. I was thinking of a small drain hole in the base of this one, or putting some cat litter in the bottom to soak up the flux.

The burner I have has about the same size as yours, 28mm bore.

bob

[John N]

The internal dims of my vertical forge are about 9 or 10" dia x 12" high. The doors about 3"sq on the front, with 1.5" sq on the back for 'passthrough'

You dont want it to small or the fuel will be out of the door before its fully burnt and left all its lovely heat inside!

[bobw]

Thanks John, might try the small bottle (7kg) it's just occured to me that I could cut a 2 or 3 inch piece of another bottle and use it to extend the forge a bit. That would give a cavity about 14 or 15 inches high by 8 inch diameter, may'be that will be enough.

Another question that I just thought of, are the top of the doors at the same level as the roof of the cavity? I've never seen a photo of the inside of these things that shows this clearly.

Bob

[Ed Schempp]

The size of the forge should reflect the size of the billet that you commonly forge. My standard starting billet is 3 x 5 x 6. My forge was 20 inch diameter and 24 inches tall. When I relined my forge I added 4 inch strips vertically to gain and extra 4 inches of billet length. My door is 8 x 9 inches to allow me to get loaves of steel in the forge. When I rebuilt the forge my half brick thick bottom with castable grout was unharmed by the flux. The bottom piece of steel appeared new. I've tried drains but they continually pool flux and being the coolest part of the forge "freeze" closed...Take Care...Ed

[van Zanten]

draining won't work, the flux just settles as soon as it get's in contact with the bricks. The bricks suck it up. The result is a moon like landscape ;-) Good luck!

[Fred Rowe]

If you have not tried hydrocarbon solvent it would be worth your time. I stopped using borax two years ago when I switched to using hydrocarbon solvent. Its not a flux but creates a canister around the billet. Another plus is you can reduce the heat required to weld.
PM me if you want to try it.

Fred