I have searched the archives and pursued the relevant forum posts
(or most of them). What I have found is a wide variation on belief,
theory, experience, and scientific (physics / chemistry approaches
if various threads.
ASSUMPTIONS (What I was Taught): Silver, Sterling Melting 1640
Specific Gravity 10.36 OzT / Cu In 5.457
Sterling (nothing exotic) Silver (Melting Temperature )
Flask sizes in the range of 2 D X 3 H
Types of waxes vary from signet rings to small charms with
Use of high quality investment
Burnout cycle roughly 9 hours; 2 @ 300f, 2 @ 700f, 3 @ 1350f, 2 @
Vacuum Casting (Solid Flasks)
Quench when button is dull grey
Because I was experiencing low success rates with some very
difficult ORGANIC patterns (very thin elements), I sought some
advice from someone who I respect (not my original teacher). I
presented the above assumptions and was challenged regarding why I
cast at such a low temperature (high delta from the melting
temperature of the alloy). He mentioned that he always casts and no
more that 150f below the melting temperature of the alloy. So, I did
some experimenting and got some interesting conclusions. The first
of which was only use casting flasks don’t try to use tin cans, they
disintegrate at the higher temperatures.
Ok, here goes a technical question looking for a solution from two
A) The physics / chemistry approach (expert)
B) The practical approach (experience based)
Why are we encouraged to cast in the range of 900f to 1150f for
Why does it seem (perception only maybe) that I get a lot less fire
scale at the higher temps?
Why do some individuals recommend not quenching but rather an
ambient temperature cooling then hammer or dig out the investment?
Why do some individuals recommend water soaking the invested flask
prior to burnout.