By Tom and Kay Benham, Contributing Editors, Lapidary Journal Jewelry Artist
It is common knowledge that soldering and fusing on a charcoal block generates a reducing atmosphere that diminishes silver oxidation and produces stronger joints. However, charcoal blocks are expensive and do deteriorate rapidly, so that we are often left with unusable small chunks of charcoal. One solution is rubbing the broken charcoal pieces into the surface of a white firebrick, thus creating the desired reducing atmosphere for soldering.