FB Board

[rbigante]

Does anyone know if the FB Board is the manufacturer's Low Density (LD) or High Density (HD) product? The HD product has higher compressive strength due to the addition of clay additives.

[dbhansen]

I may be wrong, but I think the folks here who have done the math concluded that a standard oven will exert only about 10-30 psi on the insulating board, and most of these insulating boards are much stronger than that. You should have no concerns about FB Board being strong enough for a standard oven, as many people have used it successfully for ovens of all sizes. But I don't know the answer to your question, sorry!

[rbigante]

I agree that it is unlikely that the oven will apply more that 10 psi on the board. I've located a local source for the FB board but am unable to match up the specific type (LD or HD). The HD has slightly higher compressive strength in the green and fired applications because of clay additives. I'm not sure if the clay additive would add unwanted thermal mass though or it may be such a small percentage that it would really not matter

[jpar]

I believe that the FB board is the LD type. If you can get HD, I would go with that. The HD will offer more strength after the binders in the board burn out. The difference in insulation will be minimal.