Iron Finishing & Polishing
When the cast articles are removed from the molds they are rough
and must be polished. For this purpose there are three materials
which are generally used, silica, emery, and carborundum.
Silica is sand. It may be forced by a sand blast against the articles
to be polished, or they may be held against a grindstone or an oilstone,
which is a solid form of silica.
Emery is an impure form of the mineral corundum and is used either
in the form of a powder or pressed into wheel shape.
The hardest polishing material is carborundum, which is made from
coke and sand in the electric furnace. It is crushed to a powder
and used on wheels.
After polishing, the cast iron article is ready for packing and