Casting Question

[22to45]

I only cast every few years, and I only cast for one rifle. I cast 500 grain Lee Round Nose bullets for the 45/70. Yesterday I saw something I have not seen before. I noticed that the surface of the molten metal turned blue, like cobalt blue. I have a Lee melter that casts out of the bottom, and it was warm enough that the bullets were casting fine. Any idea what was causing the color?

 

[phishroy]

sometimes it my happen if the melt is too hot.
it is a layer of oxidized alloy, usually blue and purple.
do you have a thermometer in the pot to check the temp of the alloy?
did the bullets have a bit of a frosty look to them afterwards?

 

[easyrider604]

An earlier thread mentioned this bluish surface after melting zinc wheelweights with the lead, by accident of course.

 

[hedgehog]

lead will change color with too much heat. Gold, blues, are some of the hues.

 

[SandRoad]

Bluish colours are caused by copper oxides. Zinc oxides will only produce white.

There are some lead acid batteries that have a little cobalt in them. WW made from an impure, recycled mix could have a bit of cobalt.

 

[22to45]

Thanks guys, the bullets were not frosted. My alloy is melted wheel weights, I bought 15 years ago. My technique is always to melt a few pounds of alloy, then to turn the heat way down. My total casting experience is this one mold, and probably less than 500 bullets. It kicks so hard with the load I use that I only bring it out when I want to leave an impression. I am a big fan of it though, I am sure that for short range you are as well armed with it at 1700 fps as you are with anything. I have shot a moose with it a dozen or so years ago, and I remember seeing the bullet hit it, and the big splash of blood on its horn from the entry wound.







bullets are melted wheel weights,