copper alloy question

[Tom]

I have approximately 19 lbs of a 78.7 pb, .87cu, 8.5sn, 11.9 sb alloy.
From the other site, it appears that the cu sn needs to equal the sb, if I digested it properly. If so, it looks like I should add 14 oz tin.
Some reported good toughening with .25 percent cu, so I'm thinking to mix this with 3 parts pb.
Do you think I'm in the right track for a high speed alloy, or am I missing something?

 

[Brad]

It looks about right to me.
I don't think. The copper as allowing more speed as much as it handles more pressure better. Granted more speed often means more pressure but my understanding is that adding copper makes it possible to hit the bullet harder at ignition and still have good results.
I won't use copper for low velocity or low pressure stuff, I don't see a need for the extra expense.

 

[Tom]

Thanks, Brad.
I've had a hard time digesting that thread at cb. I think 55 lbs of the cu alloy will outlast me as a hunting alloy.

 

[Brad]

That would be a bunch of hunting.

 

[fiver]

wouldn't be too much for H/V target work though.

you don't need all that tin with .3 copper, 1% tin is enough to work.
you can keep copper in solution wit a 3 to 1 tin percentage.

the antimony/copper/tin matrix is for the whole thing to be balanced and make a longer balanced chain.
now the trick question is do you want the copper in the solution or out on the surface?
that's where the antimony percentage [low tin percentage] and quenching come into play.

 

[Tom]

Fiver, not sure what I want. If I read your reply right, I'm guessing that water dropping will keep the cu in solution, and air cooling will cause it to migrate to the surface?
I have somewhere between zero and none knowledge of metallurgy, just trying to copy what others have obtained like Edd and Popper.
I did cast some 30 cal a while back, using the copper sulfate to remove zink. They had a blotchy surface. Would that be the cu migrating out to the surface?

 

[Ian]

Antimony makes mottling/circular blotches on the surface of mostly-tin organ pipes. Pb/Sn pipes are uniform in color. Solid zink pipes are darker, solid, dull grey. Not sure if that helps any.

 

[fiver]

an over tinned alloy will allow tin to migrate to the surface when it is air cooled.
if all you got is copper and tin in the alloy [or more than the antimony content] and the tin is holding the copper in solution....

now if you bind the tin and copper to antimony and water drop.
and the antimony finds its way to the surface from the speed quenching...

 

[Warren4570]

so far the cu enriched alloy i have been casting with is working pretty good. ductility and plasticity are good... pounded the 420gr 458 slug to 1/8 thick from 1.005" with 12 solid hard whacks with a 4lb hammer. no cracking or tearing on either water dropped or air quenched. The air quenched are much softer though and take quite a few less stroke to completely flatten. Both slugs were almost to hot to hold after deformation. Just begining the shooting testing on them soon.

After taking Brads advice at being a little hotter than he was to ladle pour I cast the from the bottom pour at 780 but figure the temp may be able to drop to 750 or so as it seemed most of my trouble was comin from molds that were too cool. Still working that out. Shot some from the 45-70 @ 1700 with felix lube and no leading. Still have to lap my die out a bit to get it too 460. 40gr IMR 4198 cci34 prime SL brass 2.545oal.

the alloy is at about .122%Cu. Cu+Sn = Sb @ 2.7%

 

[JWFilips]

"CU" scares the beegesseus out of me! That is why I joined a cast boolit forum
Interested if you guys can make it work!

 

[Warren4570]

My main interest in Cu is grain refining more so than High speed
plasticity, ductility, maleability where the goals to achieve.
Smashing a .460 slug from 1" to.125" thick and about 1.25 " in diameter with no tearing or cracking was pretty impressive

 

[Tom]

Warren, that ability to pound them flat really impressed me with the copper sulfate thing I did last year. I figured it might make the noe rcbs 200 hp a hunting bullet.
Fiver, I'm gathering that ac would be preferable to wd?

 

[fiver]

depending on which alloy you use.
if you really look back through those threads you'll see here is more than one copper alloy to choose from.
depending on your use of the alloy you might want to choose which avenue to pursue.


if you are interested in copper as just a grain refiner your doing It the hard way.
there are several simpler easier way's to get that done.
Tin in the 0.25% area is a grain refiner, sulpher, and arsenic are all great at this job they are also precipitator initiators [helps antimony quench harden the alloy]
copper is great at making a tough slippery alloy that Is malleable
so is antimony.
yeah I just wrote that.
antimony is great at allowing lead to slip and glide under pressure, the crystals break down and allow the lead to flow easier. [although slower]
it resists force against it slowing down that mush... yep controlled expansion. [sound familiar?]

 

[Warren4570]

I am hopefully going to test both ac and wd when I get home. I have enough cast right now to be able to do some grouping tests(50yd indoor range)..... and may even be able to blast a few into the berm at the outdoor range if the weather holds out if I get some camping n fishin tme in.

 

[300BLK]

Interesting. The 300BLK generally works at high pressure, and my water dropped range lead does pretty well, so adding a little copper should be mo betta

 

[Warren4570]

Warren, that ability to pound them flat really impressed me with the copper sulfate thing I did last year. I figured it might make the noe rcbs 200 hp a hunting bullet.
Fiver, I'm gathering that ac would be preferable to wd?

Tom it was probably one of your posts I read in one of the other forums.