Talc

Talc is a white to greyish-white fine powder which is made from finely ground talc, an extremely soft mineral compound composed of magnesium silicate. Talc is an all-purpose inexpensive filler powder which is used to make resin into a bodyfiller. Also used in resin casting to reduce cost, shrinkage and heat generated by resin curing. Catalyst should be added to polyester resin before filler powder.

Not recommended for use below the water line.