I have cast over 100 grams at a shot on my ''centrifugal
casting machine'', if you hold a tight hot flame, use plenty of
flux, and don't sit on your metal keeping tiny bits in molten stage
then i don't agree with the theory of oxygenating the metal. I have
achieved many thousands of sucessful casts. Am I missin something?
I don't think you're missing a thing. Anything to do with melting or
soldering is about heat control, right? The one thing I've noticed
about casting, and I've also cast thousands of flasks, is once you've
got a feel for it, you can break just about every rule in the book
and still get quality castings.
I would like to mention though that certain alloys are very
forgiving, especially silicon additive gold alloys which like to be
cast hot. In my experience, high copper (non-silicon or zinc
additive) alloys don't respond so well to a tight and hot torch.
Personally, I use no flux when I cast other than a glazed crucible,
and use the coolest/softest flame I can quickly melt with. My
technique has more to do with the particular high karat alloys I'm
casting than general technique and undoubtedly applies to no one