Gil Stengel on sat 11 oct 97
Try casting the firebox area of your kiln from "Bricast 3200", a catable
refractory available from AP Green. The stuff is expensive but even a 2
inch coating on your firebox will be highly resistant to sodium slag. It
comes in 100 pound bags, I believe about $35.00 a bag. I've used it in
several kilns now and have had very good results. After 100+ firings in
the salt kiln at Ohio State, there was no slag at all in the firebox of
that kiln. The box was lined with Bricast.