Plain ol' stacked firebrick forge chamber?

M

Michael Bennett

Joined
Mar 2, 1999
Messages
666
Does anyone use the simple method of stacking firebricks to build a box-type forge chamber? If so, how does it work? If not, have you tried it and found it to be problematic? I understand that a box-type chamber may have hot spots - areas where near the right angles that result in hotter or colder than ambient temperatures. Any other downsides?

My current rig is a steel cylinder lined with ash & clay. What I'm finding out is that the clay-ash mix requires LOTS of patching up. I'm reviewing options for another rebuild, and my goals for a forge are lower-maintenance, lower cost, ease of storage, minimum setup/breakdown time, in that order.

I could do a castable refractory replacement for my chamber, but a firebrick chamber is about 1/4-1/3 the cost. I figure bricks stack up and break down fairly easily. Plus, castable is only sold in 70 or 100-lb. bags in my area, something like 4 times what I'd need.

FWIW, my burner is a Ron Reil-type venturi hooked up to propane.

Thanks for your input,

Mike

:confused:
 
Hi Mike. I use a stacked forge chamber. I have several forges that I made from everything from stovepipe to freon cans. The are fine for special jobs like sword tempering and someday damascus (Ihope). I found the stacked bricks are so easy to maintain or rearrange I used it a lot more. There are hotspots and The overall heat flow is not as good but with a little practice, that's an easy problem to deal with.

I still like to make the forges but I'm the type of fellow who likes making tablesaw jigs more then making furnature.
 
Ripper, I've contemplated that one. I think that's where I got the idea to use furnace cement to seal my chamber, but it still cracks. The cracking, I think, is likely due to the different materials expanding or adjusting to the heat differently.

Peter/Dangus - this solution sounds simple enough. It might be a winner.

BTW, another option is to rebuild from ash/clay. I can see that my clay, which was kitty litter was still chunky, so maybe it didn't combine well with the ash.

Mike
 
Ash will improve the thermal reflection property of the surface of the ceramic once it has fired and then cooled back down, but overall it will LOWER your melting point on your lining, and in sustained heats it will wear faster than just raw clay. Mix very fine white silica sand in with your clay if you can get it, otherwise use whatever the best sand you can get it. This will make it form up more poorly, but it will greatly improve it's ability to withstand high heat. For even better results you can smash clinker into powder and then mix it with your clay.. In either case once you have the lining in place, get carbon into the surface as it fires by bringing it up to heat in a very dirty fire. Once you get it carefully to high fire temps you will actually fuse some of the silicates with the carbon, forming crude silicon carbide. This requires an immense amount of heat but is well worth the results. This is how I made my lining, and just for an idea of how well it works, I managed to leave a small piece of firebrick uncovered and it MELTED during the firing. This was a good AP Green brick too. It had a small chunk of about 1-2 cubic inches completely melted out of it. It has since been filled in with my homeade refractory.
 
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