ammunition-reloading, castingI’ve heard of people using everything from non-synthetic motor oil to beeswax as lubricant in bullet molds, but no information on what really provides the best release.
A friend of mine is pursuing her BFA at the University of Georgia, and she's specializing in metalworking. I know she casts metal pretty frequently, so I asked her. After warning me about the dangers of casting lead, she responded:
If your mold is made of metal (presumably steel), I use soot (if you cut off the oxygen access to your torch, you get soot-- just dust, or flame?, a layer around your mold).
Metalcasting, by C. W. Ammen confirms for me that
Lamp Black [is] A practically pure carbon (soot) produced by burning carbonaceous substances in an insufficient supply of oxygen (reducing atmosphere). It is used in core and mold washes and blackings.
Wikipedia then informs me that:
The mold cavity is then coated with a refractory material or a mold wash, which prevents the casting from sticking to the mold and prolongs the mold life.
I very much like Kroil. Most oil-based lubes need to be thoroughly cleaned from a bullet mold or the castings will not fill well. Kroil is an exception - you can brush or spray it on after your mold has cooled and it will preserve and lubricate your mold. There is no need to clean before casting again. (Note, this is plain ol’ Kroil - “Sili-Kroil” will not work in this application. Soot also works, but can be tedious and provides no preservative properties.
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