Problems with one brick forge

Alarion

Alarion

Joined
Nov 26, 2001
Messages
1,375
I made a one-brick forge using a soft refractory brick but it cracked in two upon first firing. The crack started in the middle, where the hole is.
Why did this happen?
What can I do to prevent this?
Moreover, upon trying to build a small forge with some other bricks, I encountered the same problem: ths side brick where the hole for the burner is made cracked (even if it didn't break in two like the one brick forge).
Is the hole the problem?

Moreover I don't seem to be able to get a uniform temp into the forge.
The forge is very hot where the flame enters but remains relatively cold in the surrounding area. The volume is similar to that of a one brick forge and I used a propane burner.
 
I used a one brick forge for several months, mostly just for heat treating. I attempted forging a couple of blades and came to the conclusion I needed a bigger forge.

My one brick forge also cracked. I noticed Wayne Goddards cracked too in his book. I also wired mine up like Wayne did and ignored the cracks. The little forge worked perfect.

I used two Bernzomatic torches to supply my heat and received excellent uniformity. I used two big burner torches, I now think that one could be a smaller on for the back of the forge. That way your tip wont be getting hot faster than the rest of the blade.

It worked great for me and got me started forging blades. There is a lot of fun and satisfaction for me in forging blades.

Good luck

Joe
 
Can you explain me how to wire the brick back to one piece?
I provided just one hole in the middle of the brick for the burner, you say you have two burners. Should I plug the hole and make another two to its sides?

I used a 4 brick forge with a space slightly bigger than the one brick forge today to heat a knife I'm making and forging it and it went quite well. Changed gas type (the new one is much like mapp, and contains a certain pecent of acetilene) and the forge went up to temp quickly and quickly rought the blade at temp.
I'm also trying to build a small coffee can forge It should be just enough for heat treating small blades.
I'll build a bigger one but then I'll need something more as a burner than the actual portable one :)

I think for now I'll stick to the one-brick :)
I don't have much room and I'm using it in an attic (plenty of air, luckily).
 
Alarion, I read the $50 Knife Shop book before I built mine. In it Wayne Goddard described the tendency for the one brick forge to break, and said that he just wired his back together when it did.

So when I built mine I just included the wire up front. I used a hack saw to cut 4 channels around the brick; two around it lengthwise and two around the diameter. Basically, the lines divide the brick into thirds in each direction.

Mine has developed cracks but has not broken. I'd just recommend you hold your pieces of brick together with string or tape while you're working, use whatever you have to make a channel for your wire, and then tie it all back together. Use something strong but soft, I used picture hanging wire which is almost as good of stuff as duct tape...

Good luck,

Dave
 
You can also get a length of steel u-channel to set the brick in after you wire it together. This helps to hold the whole thing together by acting as a protective base.
 
Yep, soft firebricks made of cermic fiber and other stuff. The ones used also for glassworking or pottery ovens.
You can carve them with a fingernail :)

About wiring:
If I wire it lengthwise then I have some iron wire into the forge itself, is this correct?

About burner holes:
Can I just plug the central hole in my brick with some refractory paste and make two more beside it to use two burners or should I take another brick and carve it anew?

Finally:
Will the brick crack at the two new holes?
 
The wires on mine run alongside the holes in the ends, they do not pass in front of them. The fire would burn them up. It sounds like you have a fairly large cavity in your brick, you might consider carving a new one removing less material. Just leave enough that you can place wires outside the openings.

Dave
 
I left about 1/2 - 3/4 inch per side, my bricks being the average size of a construction brick (230x115x65 = 9 x 4.5 x 2.5)
 
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