Lead Hardness

[Johnw...ski]

I have been mixing my lead with some hard scrap I have around which is mostly
Cerrotru (58% Bismoth, 42% Tin). What I have been doing is melting 30 or 40 pounds of pure or nearly pure lead and adding some scrap until I get 535 gr boolits from my Lyman 457132 mold. This concoction has worked well for the
535 gr. boolits in my 45-70 and the 335 gr. boolits in my 38-55.

I started casting for my 35 Whelen and got leading so I changed lube and this helped but didn't stop the leading altogether. Careful checking is showing the boolits to have a hardness of around 9 BHN. Water dropping does nothing for hardness with this alloy. I have added more scrap to the mix and gotten a hardness of 13.5 BHN and after water dropping 15.4 BHN but the weight of the boolits drops from 246 to 225 gr. with this harder alloy.

My inventory is: hundreds of pounds of lead sinkers at less than 8.0 BHN, hundreds of pounds of range lead that is between 8.0and 9.0 BHN, and lots of that hard alloy that is bismoth and tin.

I guess I don't have the necessary ingredients like antimony to get the hardness.
Should I just give up on this hard alloy (cerrotru) and get some wheelweights?

Need Advice,

John

[felix]

Yes, John. Use the bismuth/tin combo to add tin and increase weight for the little boolits, like for 22s. If you don't mind, please send me a pound or so of that alloy. I will pay for the 5 dollar fixed rate USPS folder. In other words, don't waste something good for another application just because you have tons of it. Corky (Sundog) and I have been using European pellets for the bismuth to bring up the weight. Bismuth is heavier than lead, you know. Adds 3 grains to a 22 boolit, and that is significant. ... felix

[runfiverun]

bismuth will add some hardness to lead but it will also add brittleness the tin helps with that.
to get harder boolits you have to have some antimony if you wanna water-drop.
if you wanna heat treat you need arsenic.
i bet if you made your mix and mixed it 50/50 with ww's your water dropping would go over 15. bhn.

[felix]

Arsenic is NOT required to heat treat. ... felix

[Shotgun Luckey]

I wonder if adding antimony would help? It would be cheaper to add a little antimony than buy WW.

[Ricochet]

Water dropping does nothing for hardness with this alloy. Back last winter I looked up bismuth-lead alloys in The Metals Handbook and found that they make a binary alloy over a wide range of mixtures. Won't get any age hardening after quenching with that, as there's no precipitation of crystals. Same with tin, binary alloys of which with lead are said to soften with aging.

[Fatman]

Johnw...ski

Where are you picking up all your Cerrotru (58% Bismoth, 42% Tin)??? And at what price. I've been looking for some in quantities up to 10 lbs. right now as I have to start switching over to non-lead for my fishing jigs and sinkers.

I can always trade you for cleaned wheel-weights if that's what you need for your casting.

Fatman

[Johnw...ski]

Picked it up years ago and don't have access to more.
I am finding out that this stuff is much more valuable than wheel weights but thanks anyway.

John


Johnw...ski

Where are you picking up all your Cerrotru (58% Bismoth, 42% Tin)??? And at what price. I've been looking for some in quantities up to 10 lbs. right now as I have to start switching over to non-lead for my fishing jigs and sinkers.

I can always trade you for cleaned wheel-weights if that's what you need for your casting.

Fatman

[Fatman]

Yeah depending on where you can find it anywhere from $26+ per POUND!!!!

Fatman

[runfiverun]

i stand corrected on the arsenic ,thanks felix.
don't know what i was thinking, had to research that one.
i had always thought that arsenic was a critical component in heat treating.

[Johnw...ski]

I have just made a deal with another Cast Boolits member to trade my 70 lbs. of Bismuth/Tin for 100 lbs of Foundry Type.

That should solve my antimony deficet for a while. As a matter of fact a long while, since I am currently shooting only one gun that needs these harder boolits.
I still have lots of tin alloy and nearly 40 lbs. of almost pure tin ingots so I think I am in good shape for alloying.

John