Jump to content
SASS Wire Forum
Sign in to follow this  
Mustang Gregg

We might have got some zinc in the mix????

Recommended Posts

Posted (edited)

I wanted to try out a new Lyman mold this morning.

And I grabbed a couple of ingots that were supposed to be made of the old tire wheel weights and solder. 

There was not supposed to be any zinc weights in them.

Well, the crap melted at a very high temp---the dross turned blue---didn't want to flow out of the bottom pour nozzle---and the bullets were about 15 grains lighter than what lino out of that mold should be.

I have only ever used wheel weights [the old ones], linotype, and solder.

So this was a new experience.

Do you reckon that there was zinc in the ingots?

 

Mustang

Edited by Mustang Gregg

Share this post


Link to post
Share on other sites

Melted out some old wheel weights and had the same problem of purple blue lead with grainy texture.  Stumped any one a asked until recently.   Guys claim it's babbit.   Still not sure if they are right.  Never seen this in 45 years of scrap lead casting but the last 2  twenty lb batches came out bad.   Hope somebody can help.  But this is a great place for people helping.      GW

  • Like 1

Share this post


Link to post
Share on other sites
Posted (edited)

Much obliged, GW.

I still have a load of it to try.  Or maybe it will go to the scrap yard.

Oh yea, besides running light weight, it is as brittle as lino.

 

Edited by Mustang Gregg

Share this post


Link to post
Share on other sites

I have about 150 lbs left of this container.  Hate to throw it away cause lead reserve is getting low after couple of thieves got 1500 lbs out of shop (along with tools and other stuff) a couple of years ago.      GW

  • Like 1

Share this post


Link to post
Share on other sites

Yep, I recently lost several "soft" sheets out of the barn. 

I reckon they were probably pure lead.

Share this post


Link to post
Share on other sites

That mix will probably work ok for cartridges, but will give a person fits in percussion revolvers, so don’t make revolver balls with it.

  • Like 1

Share this post


Link to post
Share on other sites
Posted (edited)

 

With Zinc in the alloy:

Higher melting point than normal.

Alloy is harder than normal AND lighter than normal.
 

And with Calcium contamination:

Dross lumpy like oatmeal and won't break through to the surface cleanly, except with flame played on it.

Will plug the bottom pour spout unless you run pot 75-100 degrees F higher than normal.
 

 

Yep, all those would be indications of either Zinc (from Zinc wheelweights) or Calcium (from maintenance free battery lead) contamination.   Sounds like quite a bit in the metal if you see a big increase in hardness and brittleness.

 

Quote

Do you reckon that there was zinc in the ingots?

 

My guess, yep.  Quite a bit.

 

Folks have claimed they have removed Zinc by stirring in small amounts of "flowers of sulfur" (which is powdered sulfur), which makes zinc sulfide of the zinc, AND EMITS a large cloud of sulfur dioxide gas (a lung irritant and precursor to making sulfuric acid).  I've never tried, due to those side effects.

 

Almost no way to remove Calcium from lead alloys without expensive treatments.  Although I have made some amount of cleanup by adding high-antimony lead (like linotype) to the mix, and converting the Calcium to an  "intermetallic mix" of CaSb.   That dross then has to be handled REAL carefully because it will form Stibine gas in moist air (a poisonous gas used in killing rats and also during WW I).

 

For most purposes, casters just should sell suspected contaminated lead to a scrap dealer, and their lead recovery contractor will process the lead through a high temperature purification process (a true lead smelter).

 

 

Quote

Melted out some old wheel weights and had the same problem of purple blue lead with grainy texture.  Stumped any one a asked until recently.   Guys claim it's babbit.   Still not sure if they are right. 

 

That's used horse feed!     Babbitt metal generally will mix well with lead alloys.  Except for high Copper babbitts, it  is pretty good for hardening lead because it's Tin and Antimony, mostly.   But, because there are several babbitt alloys and it's hard to tell which one you have, it's a crap shoot using it.  Sounds to me like you got quite a bit of maintenance-free battery lead in that batch.   Which can be cast, but at higher temps, and watch where you put the dross you skim off.  Will not make accurate rifle bullets.

 

The bottom line - anymore, you CANNOT trust anyone else to know what they are doing when they smelt down "scrap lead or wheelweights."

You have to sort for zinc weights yourself, you have to keep battery lead out, you need to work with small batches that you can afford to scrap if it turns out bad, and if possible, you may want to find someone who can XRay Fluorescence (XRF) test the batches you make, to check for Zn and Ca.   It is no longer as simple as it used to be to make good bullet metal.

 

Good luck, GJ

 

 

 

 

Edited by Garrison Joe, SASS #60708
  • Like 2
  • Thanks 1

Share this post


Link to post
Share on other sites

Check the Lymans Cast Bullet handbook or the LASC website either one is an excellent source for information on cast bullets and contamination of lead used.

kR

Share this post


Link to post
Share on other sites

I've had similar experience. In my case I was mixing old COWW with what I think was babbitt, scrounged from work. Lumpy dross, purple if the heat got too high and nozzle plugging for sure. 

 

At or near the melting point for pure lead, 621°F, I would get "swimmers". IOW, if I stirred in a circular motion to get the melt swirling, little bits of mystery metal would start swimming and collect in the center.

 

Unfortunately I can't tell you what metal caused the problem, however I was able to salvage the alloy. I just kept skimming the dross, while maintaining the 621°F temperature. I did try fluxing with sawdust and kitty litter, with some success. That experience ended my babbitt experimenting.

 

Copper may have been the culprit. If it were zinc, most of what I've read is that it cannot be removed. Blending will just ruin more good alloy. 

 

Access to a Handheld XRF analyzer would be a nice tool, a bit beyond my budget. I just bought some lino, and solder, to blend with COWW. (Sorted to cull any zinc).

 

 

 

 

  • Thanks 1

Share this post


Link to post
Share on other sites

The blue color is tin that is being oxidized due to the high temperatures.

  • Like 1

Share this post


Link to post
Share on other sites

Notice I did say "find someone who can XRay Fluorescence (XRF) test" rather than recommending anyone buy an XRF tester.   They run upwards from $10k.

:ph34r:

 

Some of the larger scrap yards May have one, and they May charge a $10 fee to do the test.  Since it's May, now might be a good time to ask around.  :lol:

 

Tin usually oxidizes to give you yellow dross, and it's easily reduced with most wood or oil or wax type fluxes and goes back in the alloy.    The blue dross I've not been able to reduce and have to scoop it off.   My guess is the blue is Zinc oxide. 

 

Good luck, GJ

Share this post


Link to post
Share on other sites

Go to castboolits.com. There is a whole section on removing zinc from alloy using sulphur or copper sulphate. Used the sulphur method myself. It works.use a respirator!.

Share this post


Link to post
Share on other sites

I agree it is calcium from battery lead. Had a bunch of this that was supposed to be wheel weight lead. Be careful about any scrap lead you don’t know th source of

Share this post


Link to post
Share on other sites
Quote

The blue color is tin that is being oxidized due to the high temperatures.

.....Yes, also tin makes bullets lighter . Dross is gray/black ash - Not a blue color

*** Using this alloy & a high temperature - Do the cast bullets fill out with sharp groove bands & flat bases?

*** Cast at a high temperature are the bullets frosted

 

Share this post


Link to post
Share on other sites

▲ due to all the problems with contaminated lead out there I'm pretty much buying processed lead from dealers that I trust.

 

I can get Pb for about $1.30-$1.40 per lb which is worth it to me to skip the smelting process.  Being 73 will do that to you

 

  • Like 1

Share this post


Link to post
Share on other sites

Tin won't harden a bullet much - takes about 11% Sn in a bullet alloy to raise hardness to about 12 Brinnell.

Zinc will increase bullet hardness very quickly.

Tin is slightly denser than Zinc, so it takes more tin to lighten a bullet density compared to zinc.

 

Good luck, GJ

 

Share this post


Link to post
Share on other sites

Any form of Pulmonary Fibrosis is not worth any amount of cash saved!  If your lungs are healthy try to avoid inhaling anything but Gods good air.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.