I have a question about casting flux or borax. I noticed that the
one I have (premixed Matt's) is not recommended for grain containing
silicon, which mine usually contains. I torch melt and vacuum or
spin cast. Honestly, I don't often use the flux when melting, I use
it primarily to coat the crucible. I seldom throw in a pinch during
the melt because I found it would often follow the gold into the
flask rather than completely slipping off and remaining in the
crucible. Which do you use and when?