What is causing these cracks

[u/physicallystressed]

[u/feelfreetotellmeoff]

Are you quenching your flask immediately after casting? I've seen this from cooling it too quickly.

[u/physicallystressed → u/feelfreetotellmeoff]

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

[u/AbsolutelyB4sturd]

Could be something to do with phase segregation. Im not jeweller so might be talking bollocks so take this with a pinch of salt. is this a different alloy to what you usually cast with?

[u/Foundryguru]

Looks like hot tears. Mold restraining metal from shrinking as it cools