Age Softening

[6622729]

So, I made up some alloy for 45ACP and have begun casting it into finished bullets. I'm enjoying myself and now that I've settled on a patricular mix of my scrap materials, I'd like to stay on this and cast several thousand to have on hand. I mixed 2%ish antimony lead with linotype and 40/60 wiping solder to come up with a theoretical 12.5 bhp hardness according to the lead calculator. 3.2% tin, 3.2% antimony and 93.6% lead. I water drop primarily for convenience. Can I make a bunch of these up and use them over the next couple of years or as time goes by will they soften enough to become a problem?

[old woody]

Good question & I don't have the answer as I don't have a hardness tester but I think any softening happens in the first few months & you, only lose what you have gained by "water dropping". I am willing to stand corrected :)

[OS OK]

We tested some old casts that had been put away and lost in Old Bob's shop for almost two years...they softened 1 BHN...they were clip on wheel weights.

[6622729]

So you suggest that academically they do soften but not like they change dramatically.


We tested some old casts that had been put away and lost in Old Bob's shop for almost two years...they softened 1 BHN...they were clip on wheel weights.

[OS OK]

Yeah...not sure what you mean by academically, (in theory?)...but I'd suggest that they do in fact soften but I'd also surmise that they will soften differently according to their individual mixture of Pb-Sn-Sb-As, I don't think it is a significant drop. One blend may soften more than another.
I have about 5,000 PC'd .38/357 & .45's that have been cast/PC'd and stored for future use, they ought to be over a year old, I'll check later and see if there has been a change in them. These are my casts and I know their blends...that might reveal something.
We checked the BHN drop by accident because we wanted to harden some of Bob's range scrap a bit...we weren't out to prove that Pb will soften over time. It was an accidental discovery.

[Yodogsandman]

Note the paragraph next to the oven photo....

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

[runfiverun]

you got all kinds of time to use them up.
I'm still using stuff I cast in the last century and see no difference.

[6622729]

True or or not I like that answer so I'm going with it. Lol. 45ACP is not a high pressure round so I figure anything above 10 is probably fine and natively the mix I made should be 12+. Water quenched it will end up higher. I ran the 20 pounds of alloy I'd mixed and made up another 7 1/2 pounds to cast a few more. When one gets something dialed in, it's difficult to stop.




you got all kinds of time to use them up.
I'm still using stuff I cast in the last century and see no difference.

[RickinTN]

The alloy you are using is plenty hard for 45 acp even without water dropping. I use an alloy that has about 1/3 the amount of Sb and Sn as your mix and air cool. If you lost all the additional hardness gained by water dropping you would still have an alloy that is plenty hard for 45 acp.
Take care,
Rick

[6622729]

Another good answer. :p . My OCD personality wants to keep casting these for a while. Here are a few from last night.


The alloy you are using is plenty hard for 45 acp even without water dropping. I use an alloy that has about 1/3 the amount of Sb and Sn as your mix and air cool. If you lost all the additional hardness gained by water dropping you would still have an alloy that is plenty hard for 45 acp.
Take care,
Rick

193649

[sutherpride59]

With water dropping your alloy should be plenty hard. FROM WHAT IVE READ not experience these don't age soften much unless you use ALOT of tin, I have some that were cast with way too much Sn last year and they only dropped by about .5 BHN(I tested it 3 times and took an average). If they do often it won't be enough to hurt anything. I would urge you to get a Lee hardness tester and keep good records of your alloy hardness and what your mix is. When you find the right match you want to be able to make it again. I'm darn close right now to so rounds I made last year, I lost where I had written down the specifics of the load and its taken me several weekends to get close to where I was.

[JonB_in_Glencoe]

I don't water-drop, but here is a heat-treat test I did, that may interest you...using 94-3-3...a very similar alloy, to which you mention using. I did see age softening in two months, but not enough to worry about. At the end of the thread, I posted some results with heat-treated COWW...again, some age softening with heat treated, but I had age hardening with air-cooled.

http://castboolits.gunloads.com/showthread.php?248671-Heat-treat&highlight=

[runfiverun]

with water quenched alloy it is common for it to gain and lose a little bhn on it's way to it's final hardness.
I generally let mine sit for 6 months before using them in stuff I'm trying to get ultimate accuracy from. [3 is probably good enough and 1 is close enough]

tin will retard water quenching efforts and a tin only alloy will age soften over time.

[6622729]

I have the Lee hardness tester and you couldn't pay me enough to screw around with that crazy device again. I don't know why I don't sell it off. I do have the pencils.


With water dropping your alloy should be plenty hard. FROM WHAT IVE READ not experience these don't age soften much unless you use ALOT of tin, I have some that were cast with way too much Sn last year and they only dropped by about .5 BHN(I tested it 3 times and took an average). If they do often it won't be enough to hurt anything. I would urge you to get a Lee hardness tester and keep good records of your alloy hardness and what your mix is. When you find the right match you want to be able to make it again. I'm darn close right now to so rounds I made last year, I lost where I had written down the specifics of the load and its taken me several weekends to get close to where I was.