vermiculite board in kilns

[Bert Weiss]

Has anybody used vermiculite boards to line kilns or kiln floors? If so what brand and what density?

[Stephen Richard]

I've done it for sides, but no idea of density or trademark. 25mm thickness.

[Bert Weiss]

I am evaluating based on weight, strength, insulating value, and cost. The denser V-board backed up with calcium silicate board will yield a 183º cold face with a 1500º hotface, on side walls. That is pretty good. A less dense V-board will be about 30º cooler. The floor is the radical place. I am thinking that if I cut the board up in to large bricks, it will not warp.

My 20 year old kiln lined with Unifrax HD board is in remarkably good shape considering it has been dropped a couple of times and overheated once. It will be a tough choice.

[Brad Walker]

I am thinking that if I cut the board up in to large bricks, it will not warp.

Skamol makes vermiculite bricks.

[Bert Weiss]

I am thinking that if I cut the board up in to large bricks, it will not warp.

Skamol makes vermiculite bricks.

Jim Wiles, who used to work for Skamol, now represents both Skamol and a German company. He prefers the German board for it's strength. I am thinking about cutting my own bricks something like 21" x 12" and shiplapped instead of square cut. I will immediately cover the floor with 1/4" fiber blanket, which can be either covered with more fiber blanket or replaced.

The big decision is really the walls and roof. Do I go for surface strength or light weight? I still lean towards light weight.

[Brad Walker]

He prefers the German board for it's strength.

I've bought both types from Jim and he's right -- the German board is stronger, even at the same rated density. It's also a bit larger, being one meter long, rather than 36".

Last time I spoke to him Jim said he was going to stop carrying Skamol and only carry the German stuff (which comes from somewhere in Eastern Europe -- Romania maybe -- not Germany).