Unknown alloy..

[NHlever]

About a year ago I got a real good buy on a bunch of boolit alloy. Some of it was pure lead, but most of it was alloyed to 1-15 tin-lead. It was from the estate of a metalurgist so I trust the alloy. One box of material, however was unlabeled, and I would sure like to find out what it is. If boolits are cast from it straight, the sprue is somewhat brittle, and the boolits come out way light, (200 gr for a 250 mold for example), but are perfectly filled. I fooled around some with it, and the specific gravity seems to indicate possibly a 50-50 lead tin mix, but I'm not sure that is what it is. I have over 40 lbs. of it so I would sure like to know for sure, or close to sure. Any ideas? ( I did try giving a sample to a fellow shooter who runs a recycling place, but he was too busy to test it I guess.) Since the guy that poured the ingots was a confirmed shooter, and gun collector, I doubt it is zinc, or anything like that............. oh, the melting temperature is lower than the 1-15 mix, another indication that there is tin in it.

[fryboy]

i'm not that good at it but the specific gravity test is where you need to be ( cheaper than sending a sample to rotometals and having them test it ) use the search feature to find it , it pulled up several threads for me including these two

http://www.castboolits.gunloads.com/showthread.php?t=43425&highlight=specific+gravity+test

http://www.castboolits.gunloads.com/showthread.php?t=75815&highlight=specific+gravity+test

[NHlever]

Thanks for that link, it was most helpful.

[lwknight]

oh, the melting temperature is lower than the 1-15 mix, another indication that there is tin in it.
Antimony also lowers the melting temperature when it is in the rigfht porportion to the tin content.

[leadman]

If you can't figure the alloy out, weigh some, add pure or known alloy until you get something you like. This way you can alloy the rest with the formula you make out of your experiment.
Have done this many times.

[buck1]

Make sure it casts well. get a idea of how hard it is. Then mix it with other scrap untill you get something you can use. I shoot lots of scrap that once was -WHO KNOWS-. If it casts and shoots and isnt way toxic who cares. Being from a meterlagest/shooter is most likely not old batteries or something spooky...Buck

[a.squibload]

Scrapyard near here has a handheld Xray device that tells the percentages in the alloy,
you might call around and find one.
They didn't charge me for doing that 'cause I was buying lead.

[NHlever]

I tried the local scrap yard, but they gave me the wrong information, and I'm sure they never checked the alloy. ( I had given him an ingot, and it came back with no marks on it) They told me it was pure lead, but pure doesn't cast boolits 25% lighter than 1-15 alloy. In my crude test for specific gravity, I came up with a number that was very close to 50/50 lead tin so I've been mixing it assuming that I was close on that, and the boolits cast well so I guess I have no worries. I will try the tests talked about in the link though, and see if I come up with the same thing. I guess at 20 cents a pound for over 300 lbs of known, smelted alloy, I can't complain much about not knowing the exact composition of this box.

[sqlbullet]

I had given him an ingot, and it came back with no marks on it

X-ray fluorescence does not make any marks on the test sample. It also only tests the material about 6 microns deep. So, if you sample ingot had been rubbing against a pure lead ingot on the spot hey happened to test, it would have left no mark and indicated pure lead.

Most scrap yards don't really operate those guns properly. You need to test the ingot on at least two sides, and in different places on those sides. For instance, ingots I have tested show higher than .5% iron and carbon if tested on the top. This is because any traces of iron and carbon float to the surface as the ingot cools. Test the same ingot on the bottom and iron and carbon don't even show up.

I think you are on the right track with specific gravity tests coupled with melting point. Before I got access to an XFR I had used those tests to evaluate some mystery alloys I had. I had guess they were WW alloy, and XFR showed them to be 96% lead, 3% antimony and 1%tin.

If you have of can borrow a hardness tester it will provide meaningful data as well.

[WHITETAIL]

I would just mix in more pure lead till
I got a boolit as close to the proper weight.:redneck:

[JonB_in_Glencoe]

If you haven't already,
assuming it's 50/50 lead/tin,
I'd blend a small amount with a WW alloy.
(a small amount calculated to bump up tin % to match the antimony %)
look for improved fillout and check for hardness.
Jon