Blending different lead alloys for casting boolits.

[nitro-express]

Update: Live and learn. Bullet alloy blends are identified by the % of weight of each element in the alloy.

Recently I read an old article by Jamison, in "the Art of Bullet Casting" published by Wolfe circa 1981. I thought I understood his methodology, and in order to answer a question I had about bullet alloy I contacted Rotometals, and the % of each element in a bullet alloy is by weight.


I read the Rick Jamison article in my hardcover "the Art of Bullet Casting". This article was first published in the July-August 1974 Handloader Magazine #50. I was unable to find it online.

[dbosman]

These days, it may be easier to call around to metal recycle-rs seeking one with an XRF "gun" and have what you have, analyzed.

[Scharfschuetze]

Plus one on the above post. Most of my salvaged lead is of a known content, so it's easy enough the mix and match to get what I want.

[nitro-express]

How much do Metal Recycling businesses usually charge for analyzing a sample?

[Mike W1]

I remember that article having read it years back. The fly in the ointment IMHO was you'd better be able to cast perfect bullets every time or the calculations are gonna be off. Even with the pure metals (which I didn't have) I suspect it'd be difficult to get weights exactly the same. Not a problem keeping my pistols bullets ± 1 grain but 0.1 would be pretty difficult to say the least. Anyhow I gave up chasing that method after awhile.

Calculators abound and it's not even too hard with a pocket one to get close but close is as good as it's been for me. It's also plenty good for my purposes.

[OS OK]

Are you PC'ing the casts, lube sizing, HiTek, Tumble Lube or Pan Lubing?
Are they primarily for low pressure pistols and revolvers or hi pressure rifles?

I get away with shooting pretty soft blends of unknown exact content by watching the fill-out in the mold and PC'ing them. PC has kinda changed the rules a bit on hardness until you start really scooting them out of a rifle.
You could prolly use a lot of your unknown Pb this way without having the XRF thing done.

[runfiverun]

I'm still trying to figure out how 4% of 100 isn't 4.

[OS OK]

It's a new concept there r5r...I think were prolly too old to figure it out. New math 2+2=5.

[chrometip78]

I'm new to the casting game and I've been wondering how you guys determine alloy mixes and load pressures. Unless you're buying from a Rotometals type place and have a book that includes pressure info.

So far I'm just using range scrap/lead shot, powder coated for middle of the road pistol loads. But I'm really looking forward making up some Unique 1800ish fps rifle loads. Imagine I'll have to get some understanding of what to do with appropriate alloy mix and determining load pressures.

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[Grmps]

I'm still trying to figure out how 4% of 100 isn't 4.

It's like filling a box with 4% lead and 96% balloons. Guess which will weigh more by volume.

[RickinTN]

I'm still trying to figure out how 4% of 100 isn't 4.

Me too! I've always put my mixes together in pounds and ounces, not cubic inches or cubic feet. If I'm looking for 50 pounds of a certain alloy I'm thinking I mix enough pounds and ounces of my ingredients to get there.

Take care all,
Rick

[runfiverun]

I'm new to the casting game and I've been wondering how you guys determine alloy mixes and load pressures. Unless you're buying from a Rotometals type place and have a book that includes pressure info.

So far I'm just using range scrap/lead shot, powder coated for middle of the road pistol loads. But I'm really looking forward making up some Unique 1800ish fps rifle loads. Imagine I'll have to get some understanding of what to do with appropriate alloy mix and determining load pressures.

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don't overthink it.
anything close to .5-1% tin and 2-3% antimony will get you there.
I'm not really sure what my big batch of alloy is as far as tin or antimony percentage but it's something like that.
I just drop my rifle boolits in some water after I open the mold, and dump them on a couple of shop rags for the pistols.
I'm also not too big on cleaning my casting pot or fluxing in It either.
but I have no clue what I'm doing, so don't listen to me.

[chrometip78]

don't overthink it.
anything close to .5-1% tin and 2-3% antimony will get you there.
I'm not really sure what my big batch of alloy is as far as tin or antimony percentage but it's something like that.
I just drop my rifle boolits in some water after I open the mold, and dump them on a couple of shop rags for the pistols.
I'm also not too big on cleaning my casting pot or fluxing in It either.
but I have no clue what I'm doing, so don't listen to me.
That sounds like my kind of scientific method, thank you.

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[ioon44]

My method of mixing alloy is to use a 200 gr SWC mold or any other mold that has been checked with a known 6-2-92 alloy and mix my COWW , PB and lino to match the 200 gr SWC. A few BHN + / - doesn't matter to me.

[Half Dog]

A question from the bleachers...

If you mix X% Lead, X% Tin, and X% Antimony; I assume you would be mixing by weight. Right?
I had a XRF done and it gave the results in %. Could I assume that the results show how much weight of each component is in the sample?

Signed: Confused so early in the morning

[OS OK]

Yes, they are expressed as a percentage as to their individual weight as compared to the whole in weight. Volume has to be another comparison distinct from weight because Pb, Sn, Sb, As and Cu all have different specific gravity weight...different ratios of densities in relationship to a standard they are measured by. Comparison between them would have to be expressed in simplistic terms of ratio.
How the XRF measures and determines it's percentages is beyond my knowledge of the instrument...never saw one.

That's my best understanding in layman's terms...whatever that is...?

[runfiverun]

figure everything in parts of a hundred pounds.

or just add up the numbers you have and divide by the total.
if you add 3 pounds of ww's to 1 pound of lino-type.
the math looks like this.
3+3+3+12 that makes 21.
divide the 21 by 4 to get 5.25% [that's your antimony numbers]
it doesn't need to involve calculus, and it doesn't have to be perfect.
if some of your ww alloy is a little low on antimony and you end up at 4.8% the bhn will still be 15.

[nitro-express]

A question from the bleachers...

If you mix X% Lead, X% Tin, and X% Antimony; I assume you would be mixing by weight. Right?
I had a XRF done and it gave the results in %. Could I assume that the results show how much weight of each component is in the sample?

Signed: Confused so early in the morning

Ditto on the confusion, I think I understand.

Way above my pay grade, I believe a XRF gun works on magic, or perhaps witchcraft. Is there an app I can download that will convert my cell phone into an XRF gun? :confused:

[Shiloh]

If it casts well and is reasonably hard, my alloy is for rifle bullets. I've run range lead to 1250 in .357 with good accuracy and no leading. That being said, for rifle boolits I heep better notes now. Records are never a bad thing.

Shiloh

[USSR]

Trying to make sense of this thread. First, buy only lead in it's original source where you know what the alloy consists of (i.e. wheel weights, linotype, etc.). Second, cast all the same source lead into ingots and put them in a box that is clearly marked either as to what the source lead is or what the alloy is (i.e. 4% Sn, 12% Sb, 84% Pb for linotype). Thirdly, create your casting alloy in the pot at the time you are actually casting your bullets. Hope this helps.

Don

[runfiverun]

even knowing you got ww's and lino-type doesn't guarantee the exact percentage outcome.
you have to buy foundry certified alloys to get that close.

even then they rarely tell you the cobalt, indium, iron, silver, zinc, calcium, bismuth, and copper content.
your gonna have a little trash in almost all of your alloys, it's just smaller from a 'clean' source.

[Echo]

Well - I make up WW+2%Sn and cast them into triangular cross-section ingots made in angle-iron ingot molds. I only use those molds for WW+2%Sn. Standard 4-cavity molds, flooded to make 5-lb ingots, are used for my 7/1 base/monotype + 1%Sn Mix, base being ww's or range scrap, identified on the ingot as 7 for WW's, 7R for scrap. For Foundry type, it's 10/1 +1%Sn. Both of these make about 2+% SN, 5+%Sb, and are just fine for rifle boolits. If I wish to make some pistol alloy, I take some of one of these and cut it 50/50 w/Pb, and add another 1%Sn. That is still harder than necessary, but I try to keep thing simple, because, like O'Reilly, I'm a simple man...

[USSR]

even knowing you got ww's and lino-type doesn't guarantee the exact percentage outcome.
you have to buy foundry certified alloys to get that close.

even then they rarely tell you the cobalt, indium, iron, silver, zinc, calcium, bismuth, and copper content.
your gonna have a little trash in almost all of your alloys, it's just smaller from a 'clean' source.

This ain't rocket science. A fraction of a percent isn't the difference between success and failure.

Don

[fredj338]

I feel most shooters over think the alloy thing. I couldn't even tell you what the alloy is in my practice bullets for handgun. I am pickier about my handgun hunting bullet stuff, but that is usually 20-1 lead/tin.