age softening

[Oklahoma Rebel]

with an alloy of 5.5%sb, 4%sn .6-.7cu, will age softening be a big issue? I know it would soften a little im sure, with 4% tin, but enough to make a difference? thanks- Travis

[Yodogsandman]

After initial age hardening, your base alloy should hold it's BHN for a long, long time.

If heat treating, then softening would be a concern. Alloys with a high tin content, heat treated will lose hardness much quicker over time.

http://www.lasc.us/HeatTreat.htm

"The higher the tin content of the alloy the less the alloy will respond to heat treating and the faster it will age soften. (2-3% is fine unless your goal is 30+ BHN which is very rarely needed)"

[Oklahoma Rebel]

if I drop the tin 1% will it become more brittle, or will the copper help with that?

[Oklahoma Rebel]

although, a month or so ago I did a 10lb sample batch pretty close to that alloy in my first post, it took a while, but without quenching the ingot it did turn very hard, I don't have a tester, but it is at least a few points more then reg lyman no 2 maybe 17 or 18? so I might not have to heat treat at all, or maybe just water quench as I cast them, although that can be inconsistent. I will probably just a/c and age. and use them as they are. it is a very tough alloy!

[GhostHawk]

For rifle at speeds above 1400 fps I water drop everything.

Pistol I normally don't feel the need as they are not getting pushed that hard.

I use a kids yellow plastic sand bucket like for the beach. Put an inch or so of water in the bottom. Still has 8" or so of side to help prevent splashing. I put it a foot left of my pot when water dropping.

Cut sprue, open mold over it. With some molds I can just tap the edge of the bucket and boolits will fall out. Others need a tap on the handle hinge point. Once you get a rhythm going I don't see it as being that inconsistent.

[Yodogsandman]

You could easily cut your alloy 50/50 with pure lead and then water drop the boolits for a harder and better alloy. BHN numbers are only relative, the numbers don't show the malleability of the alloy or how tough it is.

[Oklahoma Rebel]

if I ccut it in half, I could have just used cow's and 1 1/2%tin, but that's not what I wanted , I have tested qquite a few alloys in my hi-po's and this one is the best as far as accuracy, and performance. ghosthawk, you are probably right, casting is a very rhythmic thing, so I will try that. plus its so much easier then messing with the oven and all that.