Jim and all, I was the crash and bang kind of guy that stumbled on
the anti-fire scale process. The process works for vacuum casting.
A flask used in centrifugal casting can not be placed into the
reducing atmosphere rapidly enough. The arm has to stop spinning .
Firescale is forming as the arm slows and stops spinning.
My process prevents firescale from forming on castings when you
vacuum cast. I have written a paper on firescale prevention and my
process has been shown in two magazines. I would be more that happy
to send you a copy of the process if you send me your snail mail
address. The process is very simple. I place some scrap wax on a
solder pad, place the hot flask on the wax covered pad immediately
after the metal is poured. Place a larger flask around the mold
flask, place some wax on the sprue and place a solder pad on the top
of the cover flask. The wax, as it attempts to burn, forms a
reducing atmosphere around the mold flask thereby preventing oxygen
from getting to the copper. My castings come out of the quench water
with a dull finish to a bright finish. I no longer pickle them. I
have no firescale on my castings. I have polished them with jewelers
rouge directly after quench. Lee Epperson