determining alloy by weight and volume, hardness

[ok-22shooter]

In the distant past, I would cast several bullets from unknown lead alloy and then compare the weight of the bullet to the same mold poured in pure lead and #2 alloy. It was a decent way to determine the if there was more or less tin/antimony via the big difference in tin/antimony and lead density. tin = .261 antimony = .241 lead = .409

I recently scored several hundred pounds of lead. about 40 pounds in original Linotype letters and several ingots marked 4% tin 12% antimony.

Some had 90/10 marked on the ingots and one could assume 90% tin 10% lead. There are sections of solder bar that has no ratio. Then there are perfectly rectangular ingots that are bright and shinny with no markings. some ring when hit, some thud.

Density is a function of weight and volume. While I could melt samples of each, I am thinking about buying a graduated beaker and using the change in ml level to determine the volume of the ingot. Weight divided by the volume should give me an approximate density of which could be extracted an approx alloy.

Antimony might be estimated by the hardness of the lead.

Searched the forums and did not come up with any posts that addressed this. Looking for other thoughts.

[YoungGun88]

If you're near a scrap yard or metal recycler, call and ask if they have one of those fancy XRF guns, and would be able to test some of your ingots if you brought them in. They might charge a small fee(or deny altogether), but might as well ask.

-Dan

[Dusty Bannister]

Bullet samples and ingot samples have a different cooling rate and may have some variation in hardness when tested. But that might be sufficient to at least help you sort into hard, medium and soft lead. There was a nice article several years ago where an individual put a lot of work into trying to show how specific gravity was a method of determining the make up of an alloy. Which might be used if you know it is ONLY two different metals but likely unreliable with three or more metals in the alloy. Expect others to disagree on that last comment.

There is a list member that can provide XRF scan results, but while very reasonable, it would not be user friendly for a lot of different samples and does have strict sample prep when submitting.

It might be in your best interest to just accept the marked ingots as being accurately ID'd and then submit those unmarked ingots with a correctly prepared sample and call it good. At least consider doing that with the hard unidentified material in the event it is block tin, or lino ingots. Good luck and enjoy your new stash.

[JonB_in_Glencoe]

Calculating density sounds like a great way to guestimate an alloy if you are sure it's a binary or ternary alloy.

[kevin c]

I’ve never been sure how well that works. While there's no doubt that 90# of pure lead melted with 10# of pure tin gives 100# of 90/10 alloy, the exact density of the alloy depends on peculiar physical and chemical properties, not just the proportions of the metals and their density in pure form, at least from what chemistry and physics teachers beat into my thick skull many years ago. Still, the proportions do matter, and maybe an approximation is good enough. Or if you have reference numbers for the densities of the alloys in question, you might get very useful comparisons.

XRF analysis, like YoungGuns88 suggests, is what I do for unknown source metals. Besides the scrap yard folks, member BNE has done XRF analysis for members at very modest cost. PM him for details (and do follow his instructions closely, please).

[jsizemore]

We got a guy. He does an XRF test. He charges 1 lb. of alloy/lead for each test.

[JimB..]

The user everyone is referring to is BNE, no idea if he’s currently accepting samples.

For lead/tin what you describe would work pretty well, add antimony and it gets complicated, add arsenic and copper and a few other things and there would be too many combinations to make it worthwhile to create the reference alloys to set it up.

[JSnover]

The user everyone is referring to is BNE, no idea if he’s currently accepting samples.


Two years ago he did some for me.

[garandsrus]

Here you go: http://www.castpics.net/subsite2/Classics/Determining%20Alloy%20composition.pdf

The XRF analysis is the way to go! If you do this, make a batch of “similar” metals to reduce the number of batches to test and to make each batch bigger.

[35 Rem]

I don't see how you could ever calculate alloy content from density since you have too many possible contents - i.e. tin, antimony, silver, copper, etc. Many combinations could have the same density.

[jsizemore]

I don't see how you could ever calculate alloy content from density since you have too many possible contents - i.e. tin, antimony, silver, copper, etc. Many combinations could have the same density.

That's why we got a guy.

[35 Rem]

That's why we got a guy.

Yeah, I've sent several samples to BNE myself. That takes all the guess work out of it. I was just saying that you have too many variables to calculate based on density. Most of the time the exact content of an alloy isn't really required to make decent bullets. I had some that I thought had a high Tin content is why I wanted a measured analysis because Tin is always a good thing to have but it costs $$.
For various batches of "range lead" I usually just use some combination of the old reliable concrete floor drop test and fingernail scratch test to figure out basically what I have.

[dtknowles]

I think you could learn something from calculating the density of ingots. Not the actual composition but you could separate the pure lead from alloys with a lot of antimony and/or tin and those in the middle. It is the same as you comparing the weight of cast bullets of different alloys without having to melt anything. Regarding the stuff marked 90-10, I would say it is more likely 90 lead and 10 tin. It make no sense to make solder with 90 percent tin and 10 percent lead, it would not be good where lead free is required and if lead is allowed why just 10 percent. Here is some 90-10 for sale, it says 10sn 90pb

https://www.ebay.com/itm/256003873684?itmmeta=01HR41Y2VYCZRE9PHW5H34YXRD&hash=item3b9b051b94:g:V54AAOSwg4hkCN-y&itmprp=enc%3AAQAIAAAA4JGUQcJE1dYAgEc60T8qDIft78TLy YqdMcWQ1RPgC5qITpJRbvcQs0gqKdlgHvEM9%2BZ7cOLx3dnbG mtDkYdjttJbYrMwOepd1H60kCwg0D7kQ%2Fb7VNA3ViOvr4BVd l3HuRaz5CEV0zNeO7ohNx9JxuD5mkOhSxRyAukqDr%2Fjvo%2B Glsyyddmzt91CucPvUy6kU1kSNejoWibC5OAqpOLcfkEslP9z% 2FSWa9XOvN5s4ndWy5CqYjtbaBRRgyGlvlEJZsblcvREVJ%2FI %2BcKV9JHliWqpUGeysU7sGl69Qt7SwwOdx%7Ctkp%3ABFBMiq 74gcFj

The difference is measurable and this chart with g/cm3, cm3 is the same as a ml.

324096

Your 90-10 should be about 10.78 g/cm3

It is a given the more tin and antimony the less the density.

Tim

[farmbif]

im sure no chemist or metallurgist but determining unknown alloy contents by any other method than XRF test leaves lots of room for uncertainty. pure lead can usually be identified if its in pigs or those big ingots that are connected, sheets or such, but Linotype used to come in pig form also and bar solder is most commonly 50/50 or 60/40 and Linotype is Linotype

[justindad]

How much porosity do you think you have?

[Bad Ass Wallace]

"The Art of Bullet Casting" has a comprehensive chart of alloy weights and variances and is available on DVD.
https://www.wolfeoutdoorsports.com/the-art-of-bullet-casting-collection-on-dvd/

It is a method that I have used for many years. For example Lyman 311284 casts 218gn in pure lead while the alloy that works for me weighs 207.6gn (92:6:2). When I'm casting a new batch, I add to pure lead, tin and antimony until the cast weight is achieved.

https://i.imgur.com/SabiU6Dm.jpg

[dondiego]

"The Art of Bullet Casting" has a comprehensive chart of alloy weights and variances and is available on DVD.
https://www.wolfeoutdoorsports.com/the-art-of-bullet-casting-collection-on-dvd/

It is a method that I have used for many years. For example Lyman 311284 casts 218gn in pure lead while the alloy that works for me weighs 207.6gn (92:6:2). When I'm casting a new batch, I add to pure lead, tin and antimony until the cast weight is achieved.

https://i.imgur.com/SabiU6Dm.jpg

That the best you can do? Hehehehehe!

[Bad Ass Wallace]

That the best you can do? Hehehehehe!

Not as tight when I use open sights!:kidding:

https://i.imgur.com/LuRm5kSm.jpg

[dondiego]

Not as tight when I use open sights!:kidding:

https://i.imgur.com/LuRm5kSm.jpg

Looks pretty dang good to me!

[Good Cheer]

In the distant past, I would cast several bullets from unknown lead alloy and then compare the weight of the bullet to the same mold poured in pure lead and #2 alloy. It was a decent way to determine the if there was more or less tin/antimony via the big difference in tin/antimony and lead density. tin = .261 antimony = .241 lead = .409

I recently scored several hundred pounds of lead. about 40 pounds in original Linotype letters and several ingots marked 4% tin 12% antimony.

Some had 90/10 marked on the ingots and one could assume 90% tin 10% lead. There are sections of solder bar that has no ratio. Then there are perfectly rectangular ingots that are bright and shinny with no markings. some ring when hit, some thud.

Density is a function of weight and volume. While I could melt samples of each, I am thinking about buying a graduated beaker and using the change in ml level to determine the volume of the ingot. Weight divided by the volume should give me an approximate density of which could be extracted an approx alloy.

Antimony might be estimated by the hardness of the lead.

Searched the forums and did not come up with any posts that addressed this. Looking for other thoughts.

That's a part of what I've always done with lead and wheel weights, comparing the weight of one mix versus another.

[fredj338]

FOr my handgun bullets I rarely test bhn. I also weigh samples of my bullets to get a rough idea of hardness. It works fine unless I am trying to achieve something very specific.