But the real solution is to make better, denser castings. Some
folks say that spin-castings are denser than vacuum cast items.
Anyone have experience with this? I do spin casting in my studio.
Actually, casting by vacuum or by centrifuge will be problematic if
your temperatures are incorrect in your melt or in your oven
temperature. Heavy pieces will easily get pitting /porosity if your
flasks are hot… try lower flask temperature … this may resolve
your pitting problem. If it is not in the castings, then you may want
to check your steel shot for any pointed shot… like pins… these
will definitely put marks on your castings…More so on silver than
gold… If you overload your tumbler with a lot of items, this can
also cause the same problem … and even more so if the items are
heavy and/or have pointed , sharp edges.
Daniel Grandi We do casting and finishing in gold,silver, bronze
,pewter for people in the trade