Olivine sand is one of the suggested substitutes, fine alumina sand
will also work. I think you will find that there are not many cheap
substitutes. The problem is that any sand that is fine enough to
work will pose the same dangers to the lungs. It is not that silica
is inherently poisionous it is that it is not soluble by the body’s
fluids so it stays in the lungs if the particle size is small enough
and also it is so sharp that it scars the lung tissues. I believe
one of the “advantages” of olivine is it is a smoother particle but
that does not address the size issues.
James Binnion
@James_Binnion
James Binnion Metal Arts
360-756-6550