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Graphite Plumbago (Used as a parting agent with iron gives smoother finish to castings can also be used as a pig/trough wash)
Plumbago is very resistant to high and low temperatures hence its use with higher melting point metals such as iron and will prevent silica pick up on the casting. (high temperatures fuse silica to the surface in a vitriolic layer) Plumbago can be applied as a parting powder to prevent sand sticking to patterns and sand sticking to sand. It can also be dusted onto the mold after formation, or can be mixed with carriers such as water and isopropanel alchohol and sprayed on and the alchol burnt off or torch dried to evaporate moisture. It can also be applied by brush or swab on baked or sodium silicate cores and moulds.
Plumbago also has excellent lubrication qualities and moulding box alignment pins are coated with it. Oil should not be used as it will pick up sand grit and cause wear to the pins.
It is an excellent release agent when die casting and coated pins can be knocked out leaving recesses as required