Has anyone out there found a cure for rings cracking at the sprue when using
the De-ox sterling silver alloys.
I found a piece of info on the United Metals website that suggested a
"lighter" investment mix as it would be "not" as strong as the mud I usually
mix.
I like the de-ox for its anti firescale property's, but the shank cracks (
from hairline to complete cracked shanks at the sprue ) are a big problem.
So far I have tried .................
Regular sterling silver casting grain no problems.
Then comes the fun part.. switch to De-Ox grain and the problems start.

The lighter investment mix mentioned.
15{ normal} & 20 & 30 minute wait times before quenching the flasks.
At the 30 minute mark, there is almost no boil-off so I dig out the tree
with a screwdriver
Adding 2 extra sprues to the ring, pain in the *ss to clean up and no help
either.

I am using a kerr electro-melt with the built in temp controller so
over-temp is not a problem.
Casting temp is 1950 F per Rio Grande catalog. With the usual 50/50 mix of
new grain to sprue/button.
Flask temp is 1000 F for heavy stuff, 1100 F for medium stuff and 1200 F for
the fillagree type stuff.
Kerr Satin-cast 20 is investment.
My normal set-up is standard investment procedures with 1 hour setup, De-wax
in pre-boiling dewaxer, and into a pre-warmed kiln, ramp up temp 1400 and
down to casting with the usual times for heat soak prior to casting.
Thanks in advance !
Mark