?? Brass Mixing With Lead ??

[Time Killer]

I have been casting for years but just started swagging in the past couple of years. Like many of you I have a home made bullet trap that I recover my projectiles from. Some of these were for my 357 rifle and were made by utilizing 380 brass as the jacket. My pot was approximately 1/2 full of a approximate 95/5 mixture of lead to tin mixture from a previous casting session. I remelted the lead out of the swagged bullets in my casting pot and ended up with a brass looking sheen on top of my lead. When I went to start casting projectiles the lead flow was very slow from my bottom pour pot. I have read many articles where individuals use copper to create more malleable projectiles. My speculation is that the copper/brass was leaching from the brass and mixing with the tin in my lead mixture.

I would appreciate feed back from anyone that may have knowledge or experiences related to this.

[blackthorn]

Then thought that crossed my mind(?) is whether oxides from the brass might be present and, if so, if they might be reduced into the alloy when it is fluxed?? Just a thought.

[redhawk0]

I believe you're seeing the tin separate out. It will be that "yellow" color if you smelt too hot. Try some candle wax and flux it back in at a lower temperature.

redhawk

[jsizemore]

Some of the brass that gets pulverized from impact with the steel trap may go into solution. It doesn't have to melt to go into solution just like the folks that add copper to their lead alloy.

[Dusty Bannister]

If there is a concern, you might consider sending a sample to BNE and know for sure what is in the alloy. Overheated alloy often has color displays. It might also be possible that your recovered alloy still has other contamination in it or the dirt is building up on the sides of the pot. If you have a PID you will know the melt temp. If you are adding recovered bullets to your 1-19 mix, you really do not know what you have. What is your casting temp or are you using a thermometer. It could be merely a slow flowing nozzle that needs to be cleaned to return the full alloy flow when the valve is open. Dusty

[bangerjim]

You are simply running the alloy too hot. Lead and alloys get "colors of the rainbow" on top of the shiny surface when just too hot.

Cu in an alloy makes it tougher, not more malleable. I use 1% or so at times for rifle boolits and them PC them. Get mine from CuSO4 in the form of sewer pipe root killer at Lowe's. I also have a bunch of 5-6% Cu Babbitt I use to sweeten the alloy.

banger

[303Guy]

Brass is a copper zinc alloy. Could zinc be getting absorbed into the melt?

[JimB..]

Brass is a copper zinc alloy. Could zinc be getting absorbed into the melt?

It’s an alloy that doesn’t melt at the temps we’re talking about, so no the zinc won’t come out in any appreciable amounts. Could be fine brass dust floating to the top, but as is the consensus, I think it’s probably just heat and oxidation of the tin.