Warm Glass
Skamol V-1100 (600) Vermiculite Board
Skamol is a Denmark-based company that makes thermal insulating materials. One of their products is vermiculite board, a rigid refractory material that can withstand temperatures up to 2012F (1100C). In addition to being quite strong, the board is also resistant to thermal shock and can be machined with standard woodworking tools. It is asbestos free, but does contain some silica, so wearing a respirator or mask is highly recommended when you're cutting the board.
The warm glass artist can use Skamol's vermiculite board in several ways, including the following:
- Mold Boxes for kiln casting. The board can be used to build a reusable mold box for casting. This process is described in Bullseye's Tip Sheet Number 5, available for download from this page: http://www.bullseyeglass.com/connection/education/
- Kiln Shelving. The board's rigidity and thermal shock resistance make it useable as a kiln shelf. Both the 2" and 1" thickness can be used, just make certain that you support the board well with short kiln posts or other kiln furniture in order to minimize the possibility of warping. It is necessary to use fiber paper on top of the board to prevent sticking; kiln wash alone is not always sufficient.
- Drop Rings and similar molds. Vermiculite board makes an excellent drop ring. Just cut a hole of the desired size in the board, cover with fiber paper, and slump. The board is more rigid than most fiber boards or other refractory materials.
- Backing board for kilns. The combination of rigidity and resistance to heat (up to 2012F/1100C) makes vermiculite board an excellent back up insulation for kilns.
The Skamol product is available in several different sizes and densities. The one inch thickness works well for most applications, but the two inch thickness is probably better for kiln shelves. The V-1100 product, with the highest available density of 600 Kilograms/cubic meter (37 pounds/cubic foot), is most commonly used. You can read Skamol's full description of this product at the bottom of this page in the section on vermiculite insulating slabs: http://www.skamol.com/34.php Note that this page has links to several other pages of information, including a detailed description and a complete Material Safety Data Sheet (MSDS).
Please note: The Warm Glass website no longer sells Skamol, but it is available from several glass suppliers and kiln manufacturers, including Bullseye Glass, Evenheat Kiln, Ed Hoy, and others.