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lead alloy question

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23 January 2010, 08:49
Jon
lead alloy question
I just got a Lee Bullet Hardness Tester and used it to check the hardness of some 235g 45 Colt bullets I cast from old lead SCUBA weights of unknown alloy. These bullets come out .079 on the Lee scale which is a BHN of 8.0. This a lot softer than I expected since the sprue is very "brittle" compared to the known pure lead/tin alloy (30:1) I use for black powder cartridges. Also, after fluxing and while casting this melt has a colorful, mostly golden, "sheen" kind of like oil on water on it's surface. Any idea what might be in this stuff besides lead?

Jon
23 January 2010, 22:07
Idaho Ron
When I am melting pure lead 5 BHN, it is normal to see yellow's, blue's, and green's on the dross. It is normal but I think you might be a bit too hot. When I melt pure lead I don't see the different colors until it is very hot. On lead as soft as that 8 BHN I would try to back off the heat a bit and keep it stired and skimmed. I use a laddle when I make bullets. I have seen this yellow oxide come out of bottom pours. I try to not let that happen. You say he sprue is brittle. That makes me think it has some tin in it and the melt is too hot. Ron
24 January 2010, 01:59
Jon
Thanks for the comments Ron.

You're probably right about it being too hot. I melted the lead in a cast iron pot over a propane burner and was not able to control the temperature as well as with my electric furnace. The thermometer was always somewhere between 700 and 800 deg. which is too high. I think I need to try casting some more bullets at lower temp. and get more experience using the hardness tester.

Jon
25 January 2010, 01:17
Idaho Ron
I have a cabin tree tester. I have seen others work, and on another forum I have compared my tests with other testers. The cabin tree is an amazingly easy and accurate tester. Ron