Zinc Test or Identification?

[PBSmith]

I recently came into a supply of .50 caliber slugs that someone had apparently been reloading into 50-70.

I don't intend to use these because:
1, they are way oversize for my rifle, and
2. they are way too hard, need a sharp instrument just to scratch.

If these bullets are linotype, I can use them with soft lead for a decent alloy.

It occurred to me that they might contain zinc.

Is there a simple way to determine if these bullets contain zinc?

I don't know that I would go to trouble of trying to remove the zinc if it is present, but that's putting the cart before the horse.

[dondiego]

Test it with a drop of muriatic acid (Hydrochloric Acid) on a clean spot. If it bubbles, zinc is present.

[Rickf1985]

If you do not have any acid or you don't want to buy any and you do have a lead pot with an accurate way to monitor the temps you can bring some regular lead in your pot (whatever you have in there is good enough) up to 600 and get it stabilized there and drop one of those slugs in and see if it melts. If yes then you have a high tin alloy. If not go up to 650 and try again and if it melts mow then I would say you have an alloy higher in antimony. Zinc will not melt until around 750 but I always keep my pots at 700 or lower when smelting large lots of lead and wheel weights and any zinkers always float to the top. You could go to 700 and try it but if it does not melt in a few seconds I would pull it out. One zinc slug in a full pot of lead will do no damage at all but this info is just to give you ideas on how to test what you have. If you have a lot of this lead you might consider sending a sample to BNE and have him analyze it for you. Then you know for sure what it is and how to modify it.

[dondiego]

If you do not have any acid or you don't want to buy any and you do have a lead pot with an accurate way to monitor the temps you can bring some regular lead in your pot (whatever you have in there is good enough) up to 600 and get it stabilized there and drop one of those slugs in and see if it melts. If yes then you have a high tin alloy. If not go up to 650 and try again and if it melts mow then I would say you have an alloy higher in antimony. Zinc will not melt until around 750 but I always keep my pots at 700 or lower when smelting large lots of lead and wheel weights and any zinkers always float to the top. You could go to 700 and try it but if it does not melt in a few seconds I would pull it out. One zinc slug in a full pot of lead will do no damage at all but this info is just to give you ideas on how to test what you have. If you have a lot of this lead you might consider sending a sample to BNE and have him analyze it for you. Then you know for sure what it is and how to modify it.

What is the melting point if the alloy is 10% zinc and 90% lead? 50/50?

[Rickf1985]

I don't know, I think what you will have is an oatmeal looking mess the higher you get in the zinc range. The fact that you have decent bullets already in this alloy I doubt you are going to find much zinc if any at all. Definitely not 10%. I forget what the limit is before an alloy is considered ruined by zinc but it is low, no more than 2% I believe. Zinc does not alloy well with lead so above a certain point you will not be able to get anything that looks like a bullet out of a mold. You can mold pure zinc, but do not use aluminum molds. And bullets will be very light. And very, very hard.

[Dusty Bannister]

You might save some angst if you just look through the illustrations of various 50 caliber bullets and see if you can ID that bullet by mold number. Then see what the nominal cast bullet weight would be based upon the alloy that maker uses. You can compare the weight against common alloys in the LASC site. Checking the weight it might help you determine how likely the bullet is cast from Lino, COWW or some zinc alloy which would be far out of the expected weight range.

If the casting is crisp and well filled out, it probably has little if any zinc in it. Being very hard, it might only be HT/Q common lead-tin-antimony alloy. Do the simple stuff first. If you have a significant amount of these bullets, then the XRF method is the only way to determine exactly what you have. If you only have a few pounds, just run the casting furnace down to about a half pot, add one bullet, flux and cast some samples. If it is trash, then you are only out a small amount of alloy or just add good metal to dilute the issue and move on.

[JonB_in_Glencoe]

What is the melting point if the alloy is 10% zinc and 90% lead? 50/50?

Zinc-Lead alloy's have an interesting "Bell" shaped curved on the Melt temp chart.

10% zinc and 90% lead
1200º F (650ºC)

50/50
1468º F (798ºC)

https://www.researchgate.net/figure/...ig15_215730693

[JonB_in_Glencoe]

I don't know, I think what you will have is an oatmeal looking mess the higher you get in the zinc range. The fact that you have decent bullets already in this alloy I doubt you are going to find much zinc if any at all. Definitely not 10%. I forget what the limit is before an alloy is considered ruined by zinc but it is low, no more than 2% I believe. Zinc does not alloy well with lead so above a certain point you will not be able to get anything that looks like a bullet out of a mold. You can mold pure zinc, but do not use aluminum molds. And bullets will be very light. And very, very hard.

Some of your beliefs on Zinc alloys is incorrect.

[Rickf1985]

Ok, I never said I KNEW for sure but would you care to elaborate? Do you actually know anyone casting bullets at 1200 degrees? Or anyone actually casting 10% zinc bullets?

[JonB_in_Glencoe]

Ok, I never said I KNEW for sure but would you care to elaborate? Do you actually know anyone casting bullets at 1200 degrees? Or anyone actually casting 10% zinc bullets?

Last first...
-I do not know anyone casting with 10% zinc.
-I do not know anyone casting bullets at 1200ºF

I do know the following isn't necessarily true...
"I think what you will have is an oatmeal looking mess the higher you get in the zinc range"
" I forget what the limit is before an alloy is considered ruined by zinc but it is low, no more than 2% I believe."
"Zinc does not alloy well with lead so above a certain point you will not be able to get anything that looks like a bullet out of a mold."

For all three of those, the temperature (of both alloy and mold) just needs to be hotter.

[dondiego]

Before I was fully aware of zinc wheel weights I was just melting them as I needed. I finally got the oatmeal and it was thick. I just added more lead and it got diluted enough to use up on bullets.