Kiln wash is used to prevent hot glass sticking to kiln shelves and fusing glass molds. Also known as shelf primer or glass separator kiln wash is a method used to prevent hot fusing glass sticking to a kiln shelf.
This is a cheaper method than using shelf paper but it will produce a slightly rough finish on the back of the fused glass piece.
It is also used as a coating for glass fusing slumping and drop molds.
For jewelry making it is used quite often on molds to produce frit based jewelry pieces as per photo of the coated jewelry mold on theleft .
It comes in a powder form and is mixed with water as per the makers’ directions.
Caution is needed when handling the powder and a respirator should be worn to prevent inhaling any dust.
The wash usually has a colouring agent that will burn off during firing; this allows you to tell if the shelf has been fired.
Wash is normally applied to the shelf or mold with a special soft brush known as a Haike brush; these brushes come in various sizes.