Hello All,

I'm in the process of building a large brick-pile forge and I'm running into some problems. The forge is big enough to put a 24" x 24" piece of sheet metal into it. It has 2" of fiberboard and 1" of fiber blanket in the top. It seems that the 4 large jets are putting too much heat into the forge because the top sheet metal on the forge is bowing up quite a bit. I am considering putting a 2" layer of 3000 degree refractory cement in the very top of the forge and then the 2" fiber board under that. I hoping that the heat that seeps through the fiberboard will get soaked up and dissipated in the refractory. Any thoughts?

That's a big forge. Have you tried cutting back one burner once it's up to heat?

Otherwise I don't see anything in your plan that wouldn't work. connecting the refractories so they don't fall off the lid will probably be the biggest trick.

I think I'd use another layer of board, I assume you're using something like Kaowool ceramic fiberboard. There is an insulating version that would make a good outer layer, it isn't rated to as high a temp but if it's not in contact with the fire it should be fine.

How about some pics of this bad boy at heat?

Frosty

how about a layer of fire brick ???

I will post some pics of the finished design once it's up and running smoothly. It's pretty kick ass now but I don't want to give any visual references until I know it's perfect. I'm on the 3rd re-design now.

I have a steel frame that will hold the refractory in place so I don't think that will be a problem. I'm thinking of putting steel rod in the middle when I pour the refractory, sort of like rebar in concrete, but I'm not sure if the expansion rate of the refractory is the same as the expansion of the steel. Does anyone know?

Does anyone know if refractory holds in heat better than fiberboard? I assume it does sense every kiln I have ever seen is made with it and they don't put out excessive heat.

I think I'll stick to the refractory because it will be easier to keep in place than a bunch of firebricks.

Would it be useful to put a gusset or a stiffener on the top sheet metal.. if it is bowing from heat to guide where the expansion is going?

Are you going to put the refactory/brick on the inside or outside of the top sheet?

I thought of reinforcing the top but that's kind of a band aid approach sense the top should not be getting that hot anyway. If the refractory does not work then I may end up doing that but I'm hoping not to have to.
I'm planning on putting the refractory under the sheet metal but then again with the hardness of the refractory I may not need sheet metal at all. I would of course have a steel frame around it to help keep it together.