While I am an long time Orchidian I have been taking a break from
everyday reading, but find myself often looking through the archives
for answers to my questions. What a wonderful resource we have here,
so thanks Hanuman!
My question is in regards to some 14 KPD rolling grain I purchased
from Stuller recently. I melted it into what I believe is a new
silica crucible seasoned with a light coating of boric acid. The
first casting was not to my liking so I remelted it in the same way.
I rolled it being careful not to reduce more than 50% then annealed
it, to orange heat, probably too hot, allowed the metal to cool on a
steel plate. Of course the next few rolls cracked it, but only
superficially. I was able to grind those fine cracks away.
Re-annealed to cherry, quenched in alcohol (after reading what Peter
Rowe suggested) rolled several more times then a big crack! The
metal has cracked on only one side, the other looking perfectly
fine. Anyone know what’s going on here? Contamination? My fuel is
oxy-propane, annealed with a slightly reducing flame.
Can I remelt the metal and try again, or do I need to add fresh
metal to the mix? Stuller thought there might be iron contamination
of the metal, but I have no idea how that might have happened. My
pickle pot has a ceramic liner, could there be iron oxides leaching
from that? Stuller suggested using a graphite crucible and quenching
in water after red color is gone from the metal. All the graphite
crucibles I can find are not sized for the small studio.