Question.

fiver

Well-Known Member
Tin itself has a fairly high BHN number.
I don't remember it for sure but 35 comes to mind.
of course it being cut in half with pure lead will drop it.
the other part of it is tin only lead alloys will age soften over longer periods of time.
 

CWLONGSHOT

Well-Known Member
OK that means something to me. I have one single 50/50 bar thats decades old. I have had it FOR EVER!! I read it and it was about 12 bhn. When I tested my "NEW" 50/50 it was as high as 18.

Now I question is will he be harder again after I melt and mix and cast? Or has it "lost" its hardness.

CW
 

Brad

Administrator
Staff member
Hardness from aging or water dropping may come and go but as long as the alloy hasn’t changed it can be brought back.
Hardness testing ingots is a fools errand. The bullets cast from the ingot will cool at a vastly different rate and that affects hardness. Heat treat them and it matters even less What the ingot tested for hardness.
 

fiver

Well-Known Member
alloy doesn't lose it's components so a re-fresh by casting it again brings it back.
conversely you can't bump the hardness more and more by speed quenching the alloy multiple times.
 

CWLONGSHOT

Well-Known Member
Tonight I mixed up and cast some 10:1 alloy. It was notabs exact as 16:1 I did last night. But if anything its 9:1.
Same as last night I measured three as cast and three after PC/quench.

Results where nearly IDENTICAL to 16:1. 8 and almost 10 BHN.

Bagged and tagged. Will test in coming weeks.


CW
 

CWLONGSHOT

Well-Known Member
Almost ten days in. I checked again last night be cause I made up some 16:1 and added some 6% antimony alloy. 5# total with 10oz 6% alloy.

New first. Mold dropped air cooled 10 hrs after 8 bhn. Water quenched 10bhn.

10:1 from 10days ago is 10BHN as well.

Im trying to get a alloy that nets me 10 and quenchable to 15+. I can make it far harder simple Simon. Trying to reach that middle ground is proving more difficult.

To ight Ill try again. Pot almost empty but some remains so wont be a 100%. Dosent matter really as my guy will analyze and what ever is in there he will add to duplicate.

CW
 

fiver

Well-Known Member
tin only and high tin content alloys do not react [well] to speed quenching.
the quenching works on antimony.
think about it like the antimony chain is broke apart you speed cool the alloy and those pieces of antimony are spread out and not tied into a long molecular chain.
they are frozen into place affecting more of the lead because they are now touching more lead through more surface area.
tin is on the surface and retards the effect, plus it has a different shape to the molecule so it just is as it is.

12 and 18 BHN are a gimme with the 2.5% alloy I mentioned earlier.
dropping it down to 1% tin and 2% antimony should put you right where your looking [or close enough nobody's gonna know the difference]
you can add tin until your blue in the face but it has it's limits and it isn't BHN adjustable except for adding or subtracting more 20$ a pound tin.
that just isn't cost effective in the least when you have to add 100 or 150 dollars worth of tin to every 100 lb batch of alloy.
 

CWLONGSHOT

Well-Known Member
OK. So again APPLICATION of how much us where uts lacking the whole 6% it got me all twisted. I was given 6% alloy. But it tests like 7bhn?????

I have lino I can make hard NO ISSUE!!! I want 10 bhn outta the pot. (Like a week later)

Seems I can only get 6-7 or 15-16.....

GRRR. Im ready to melt and dump my pota...

Gonna melt lead and 25% lino with a splash of tin tonight and see what that gets me.

CW
 

fiver

Well-Known Member
if that 6% [antimony? right??] alloy has been subjected to stress or pressure the BHN will be low.
if you melt and cast with it you will see close to 15 bhn air cooled.

I know it's confusing, but just because antimony is present it doesn't necessarily mean you will have a high BHN number.
also your alloy can vary slightly from batch to batch in final BHN numbers. [even if it is foundry certified]
so 1-2 BHN is meaningless,,,, it really is.
I try to keep my stuff in a window just in a window, remember that is the whole principle behind the Audette ladder test.
your looking for a window of powder loads that will give you the best chance of close-nuff being good enough for the rifle your shooting.
 
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