Boron nitride is a synthetic material that's
available in several forms, including powder, solid, liquid, and
aerosol spray. Most types of glass will not stick to boron
nitride; as a result, the liquid and aerosol forms can be used in
kiln-forming as a release on slumping molds.
Although boron nitride is much more
expensive than kiln wash, it does have several advantages.
Applied correctly, it is smoother than kiln wash. It's also
less dusty, and may be less likely to mark the slumped glass than
kiln wash. It can be used on both stainless steel and clay
molds, but most formulations of boron nitride are not suitable for
use on the kiln shelf.
Depending on the quality and purity, liquid
boron nitride may be used as is or diluted with distilled water.
It works best when diluted to the consistency of whole milk.
Boron nitride aerosol sprays can be used straight out of the can,
and no mixing or diluting is necessary.
In general, boron nitride is rated for kiln
use only to around 1550F/840C. Some varieties of the product
will claim higher rated temperatures, but usually this refers to the
product's use in a reducing atmosphere, rather than in the oxidizing
atmosphere typical of most kilns.
Tomorrow's tip will contain
specific information about using boron nitride on slumping molds.
Copyright 2005 Brad Walker.
All rights reserved.