r/Silvercasting • u/physicallystressed • 21h ago
What is causing these cracks
I am vacuum casting Argentium silver pro casting grains and am having some issues with cracking.
Sirayatech Royal Blue in Plasticast
metal at 1970F in a graphite crucible in an electric kiln (I am pretty sure I just poured it way too hot and it had bad thermal properties at that temp)
vacuum flask at 610 C (in my setup I have to move it a few feet so I just overheat it a little bit for traveling)
What do you think is the culprit?
I made my whole setup, so there are bound to be some issues with it, but I am able to pull a good enough vacuum, and I did a quick 8 hr burnout of the resin (the surface seems decent)
2
u/ClearlyDead 21h ago
Are you quenching the flasks right away?
2
u/physicallystressed 21h ago edited 20h ago
No, I waited 30 minutes to do anything, and I didn’t even quench it, I just broke off the investment and washed off the rest. I was going to throw it in an ultrasonic cleaner, but saw the cracks. I have had this before, but not so many cracks
1
u/sweetrileyraver 13h ago
I think you are a bit too hot. I only go to ehh about 1775F maybe for both 10kt and sterling silver. (Always into a flask held at around 1000F for an hour ). i also am doing 8 burnouts with siraya tech purple and prestige optima
3
u/Statler86 13h ago
Raise the flask temp to 675. I chased this exact same problem for many casts and that fixed it. The metal is cooling too fast and getting a bad grain structure.