bullet aging??

[sisiphunter]

Hello,

I know that aging a boolit will harden it. My question is generally how does this work???? Will they continue to harden and age over time (years), or is there a stopping period??? Is oxygen required for this process?? I commonly store my castings in baby food jars (large/tall ones) is this haulting the hardening process???

Sorry for so many questions, though I know they are all related.

Matt

[runfiverun]

the aging period is as short as 7 days and as long at a month.
the alloy is just returning to it's actual hardness.
air isn't gonna stop it or speed it up.
they alloy is only going to reach it's hardness and stay there not get softer nor harder.
unless it oxidizes then the oxides are much harder.
this is for a regular air cooled alloy.
waterdropped and heat treated alloys act much differently.

[felix]

Aging can be dramatically accelerated by heating the boolits at 200 degrees for 2 hours. ... felix

[montana_charlie]

I know that aging a boolit will harden it.
Age hardening varies with the composition of the alloy. Some harden more than others, and some harden faster than others.
Also, some alloys are more stable in maintaining a given hardness than others. Those with a small amount of antimony seem to be more stable than alloys of just lead and tin.

This chart illustrates a small part of the results obtained by Dan Theodore in a 28-week experiment aimed at determining how alloys harden over time. All of his alloys were made using certified metals, all were air cooled, and he used the Lee hardness tester for his readings.

In all cases, he was testing alloys in reference to bullets used in BPCR shooting. Therefore, the alloys are quite 'soft'.

It appears that 1.5% antimony is the minimum amount required for stabilizing the hardening of an alloy.

http://castboolits.gunloads.com/picture.php?albumid=88&pictureid=1530

CM

[sisiphunter]

ok, sounds good....great info there, so I guess this brings to mind a few more questions...I use a fairly soft alloy about 50/50 ww to lead (range scrap)and I water drop. After they are nice and dry I use Lee Liq Alox, usually one good thick coating, then they go into baby food jars to wait for use. I am just wondering if by putting them in these fairly air tight jars if going to stop or pause the hardening process???? I wouldn't think so, but was just interested......(maybe I should poke a few holes in the tops???)

Also, one reply said the water drop bullets age harden different, how so???? I figure they may not age harden much compared to dry dropping since they are rapidly cooled???

Matt

[Dale53]

I use a "rule of thumb" - most of the hardness will be reached in two weeks for the alloys I use for bullets.

That said, more than once I have shot my bullets a day after they have been cast (various alloys). I have not seen a difference in performance...

Some bullets have been cast, lubed and stored for years in a garage (no heat or cooling but a closed garage) and shot them without a loss of performance.

I draw NO conclusions but mostly don't worry about aging... but I AM aware of it's effect on hardness.

Dale53

[243winxb]

Heat treatment/water drop info here. http://www.castpics.net/memberarticles/arsenic.htm
I am just wondering if by putting them in these fairly air tight jars if going to stop or pause the hardening process???? No. Bullets in jars are in air, same as outside the jar, so it should not make a difference unless sitting in the hot sun, lube would be affected. Plus the lube is a protective coating from the air, so they are not really in the air . An alloy of lead/tin air cooled, would get softer in about 1 year. 2% antimony water dropped does this. http://en.wikipedia.org/wiki/Grain_boundary_strengthening 2% antimony/lead hardens fully in about 3 week, who knows why, not me. 6% antimony/lead hardens in 30 minutes water dropped.