The Dec 2000/Jan 2001 issue of Machinist's Workshop magazine has an article by Mr. Steve Acker titled "Making a Chamber Casting". He describes the complete process for using cerrosafe alloy. The mag is available from Villege Press, 2779 Areo Park Drive, PO Box 629, Traverse City, MI 49685. Phone (800)447-7367. The cover price is $4.50US.
As the material is copyrighted, I will not attempt to render it all here. But the salient points seem to be:
1. Cerrosafe alloy 158-190 degs F
2. Better to have barrel removed.
3. Barrel should be clean & between 70-100 degrees.
4. He gets good results by spraying WD-40 in barrel & removing excess with compressed air.
5. Plug barrel about 2" in front of the neck with clean cotton patch.
6. If possible, pour through a long necked funnel, so the pour begins as far into the chamber as possible.
7. Remove the casting as soon as it solidifies.
8. Wait 1 hour before making measurments.
Enjoy
John R.
Seneca, MD