How I alloyed pure antimony to pure lead

[lign]

Hello All,
I had a lot of trouble finding info on alloying pure antimony with pure lead so I thought I'd share what I did. There's plenty of info on this site and others but it all gave me the impression that it was extremely difficult. It was extremely simple and easy and there's no need to spend a fortune for pre-mixed stuff.

Most of the boolit metal I have accumulated is pure soft lead. Where I live (Florida), it is fairly plentiful if you patiently watch craigslist and drive a bit. Lots of boat ballast, diving weights, and other types of ballast from scrapped machinery. Anywho, I have around 500 pounds of it at this point and my stash of wheel weights is getting low so I bought 5 pounds of pure elemental antimony on eBay. (It is really pretty, sparkly stuff!!) I am lucky to have a source of free tin (they save the dross for me from a lead-free wave-solder machine at work so I get probably 20-40 pounds per year). However, you can also get some the way I used to collect it by scrounging thrift shops and buying pewter.

I wanted an alloy of 93% lead, 3.5% tin, and 3.5% antimony. Although some might consider this too soft, I Powder Coat my bullets so it's not as important. I plan to use these mostly for 9mm & .380 to start with. I'm sure this method would work fine for other ratios.

When I clean and pour my lead, I use mini-muffin tins as ingot molds in order to have some small ingots to get exact weights for mixing alloys. I weighed 9.3 pounds of my pure lead ingots. Then I weighed 0.35 pounds of tin and chose pieces of antimony to weigh 0.35 pounds. Then I used a Lee 20 pound pot (I bought an extra pot specifically for mixing alloys because I don't want to dirty my nice Lyman 25 Mag furnace and foul it's spout by emptying it completely).

I melted the pure lead first with the pot set about 5. Then I put in the tin and let it melt. You MUST put in the tin first as it helps the antimony to dissolve. Then I fluxed with sawdust. I have regular flux but I DON'T use that (mine is Frankford, similar to Marvelux) I don't use it because I read that your alloy metals preferentially oxidize faster/more than lead, so you are removing some of your hardness metals when you use it. I bought a spring-loaded stainless steel mesh ball for making loose-leaf tea as well as a small stainless steel kitchen sieve. I bent the handle on the sieve to 90 degrees.

I first put a piece of antimony in the stainless mesh ball and SUBMERGED it in the lead. I moved it around under the surface a while and it started to melt nicely. It was taking a few minutes, so I grabbed a pair of all-metal vice grips (no rubber handles) and GENTLY clamped the ball handle to the top sides of the pot and gave it 5 minutes or so. It melted perfectly. The ball was too small, so I next put all the rest of the antimony in the pot and used the sieve with the handle at 90 degrees to submerge it and again clamped it to the side with the vise grips to hold it under. Another 5 minutes and it was all melted nicely.

Then I fluxed a few times and commenced pouring my new alloy into ingots. After fluxing with the sawdust again, there was almost no junk on the top to skim.

Please note that there are crucial safety considerations here that I don't want to take the responsibility to address. You need to look up health and other risks of antimony (serious) and take appropriate steps to protect yourself.

I hope this helps someone, and I'm glad to answer questions if I can!

[samari46]

Have heard about alloying antimony with lead/tin alloys and your description has to be the easiest one I've come across. Many years ago a buddy who worked in a chemical lab gave me a small bottle of more than likely the same type of antimony such as you described. Never used it as most of my bullet casting is/was done with just wheel weights plus 2% tin. Nice to know that the antimony can be easily alloyed with lead/tin alloys. Too darned hot in the garage even with both doors opened. May have to try this when it cools off down here. Frank

[lign]

Thanks for the reply, Frank! It's HOT here too Hardening lead alloys is easy and WAY cheaper than buying it. I guess I should have written my post about a quarter of it's length, but I tend to ramble
I wish I had tried this sooner and not just taken everyone's word for how hard it was or that you need some special flux. I think that the main important things are: 1)make sure you put in the tin first, 2) submerge it while melting, and 3) use sawdust to flux, not Marvelux-type fluxes.

[GregLaROCHE]

I was looking into doing it once and spoke with someone who had done it. He said you needed to the pure lead very hot, glowing red and add the antimony, stirring well. After it was alloyed he would let it cool down before adding the tin to keep from cooking it off at the higher temperature. He said he would often alloy just the lead and antimony and cast ingots. Later he would add the tin just before casting.

I never tried it. This is just what someone once told me.

[lign]

I was looking into doing it once and spoke with someone who had done it. He said you needed to the pure lead very hot, glowing red and add the antimony, stirring well. After it was alloyed he would let it cool down before adding the tin to keep from cooking it off at the higher temperature. He said he would often alloy just the lead and antimony and cast ingots. Later he would add the tin just before casting.

I never tried it. This is just what someone once told me.

Hi Greg, Thanks for the reply! If you put in the tin first, the antimony melts pretty easily at normal temps. I didn't time it but I'd guess 5 minutes or so. A lot slower than tin, but not bad. There's an engineer who wrote some pretty technical reasons about why(I can post links if anyone is interested), but the bottom line is that if you put in the tin FIRST (and as much tin as antimony) then it is easy. The Lyman Cast Bullet handbook and the NRA casting book are helpful but not clear at all about how easy it is.

[GregLaROCHE]

Hi Greg, Thanks for the reply! If you put in the tin first, the antimony melts pretty easily at normal temps. I didn't time it but I'd guess 5 minutes or so. A lot slower than tin, but not bad. There's an engineer who wrote some pretty technical reasons about why(I can post links if anyone is interested), but the bottom line is that if you put in the tin FIRST (and as much tin as antimony) then it is easy. The Lyman Cast Bullet handbook and the NRA casting book are helpful but not clear at all about how easy it is.

I’m sure you are right especially if you have done it that way and it worked. I was just recounting something that I was told. I never pursued it, because I found out that the range scrap I was collecting, was already hard enough for my use. In fact it’s the opposite for me now because I need to find pure lead for my muzzle loading guns and that’s not as easy.

[winelover]

I like to keep it simple. Mix lino and pure lead, in different ratios. Three parts pure to one part lino, usually. Used for most of my shooting. BHN is 13-14 after one month, air cooled. If you want harder, cut the lino at two to one. I don't even add any tin.

Winelover

[kevin c]

Thanks for passing on your experiences and techniques (though I might suggest that you're kinda coming and going at the same time when you describe how easy it is [and it sure seems so] but don't detail what you say are important safety considerations).

Maybe what has been described as difficult before is making just the binary alloy of lead and antimony, especially at high Sb concentrations. The more typical lead bullet casting alloy has antimony for hardness, and tin added to improve casting charactistics, but I've read articles by metallurgists that say in balanced alloys where the amounts of Sb and Sn are the same, the two sort of combine with each other in the lead and actually improve the characteristics of the alloy further. Maybe one effect of the tin being present is that it helps the antimony dissolve and stay in solution.

Anyway, thumbs up on describing your technique and how well it works (though describing the precautions you took, with appropriate disclaimers and warnings, would be helpful, too).

[samari46]

Don't worry about rambling when doing a post. I do it quite often and sometimes loose track of where I'm at. Frank

[Steve Steven]

Many years ago, I was into casting heavily and wanted to add antimony to some lead. I found that trying to melt antimony released LOTS of fumes (antimony oxide?) that could not be good for someone.


I posted this years ago, my experience:
I fitted a stainless pot with a close fitting lid made with solid insulation material (fitted into the pot) and laid the lead and antimony into it (50-50) and melted the two with a oxy-acetylene torch (took red heat to bottom of pot), had to guess when the two were melted together.

Only got a small amount of fumes out, the two made a nice alloy and blended in with pure lead just fine. My experience.

Steve Steven

[Burnt Fingers]

The antimony isn't melting. It's dissolving.

There is a big difference.

[bruce381]

The antimony isn't melting. It's dissolving.

There is a big difference.

Yes the tin helps to solubilize the antimony and what you did is just as I remember how to do it vs just dumping some in the lead melt.

[lign]

Thanks for the replies! I repeated the process again tonight to get another 15 pounds of alloy. I didn't time it but it seemed maybe 7-8 minutes-ish to dissolve the antimony once it is submerged. I plan to do this with the big cast iron pot I use for melting and cleaning lead and wheel weights so I can do 40 pounds or so at a time.

Kevin, I read a post mentioning it took an hour to alloy antimony into boolit metal. Not sure if that was because it wasn't submerged or because the tin wasn't added first, or something else. I'd be glad to share the safety precautions I took, but I doubtless missed something so it seems more prudent for folks to look up dangers of antimony/tin/lead and make sure they do the things they feel are necessary. Sharing what I did risks suggesting that I am recommending it as adequate. I wore an N95 mask, a clear face shield, nitrile gloves inside my welding gloves and did it in a well-ventilated place and tried to keep antimony dust to a minimum. I doubt that is sufficient (although the reading I did from the EPA's antimony concentration exposure guidelines made me feel it was enough for me). I'm not recommending this, just sharing what I did since you asked.

Steve, Were the fumes something you physically noticed, or something you read about? I didn't notice any visible fumes, although that doesn't make me think they weren't there...

Burnt Fingers, You are absolutely correct about the terminology.

Thanks all!

[Wartrail]

I have 90 pounds of Linotype that doesn’t blend with pure lead. HELP?

[kevin c]

I have 90 pounds of Linotype that doesn’t blend with pure lead. HELP?

Folks who might be inclined to help might not see your post here, as it's not part of the OP's topic. Maybe start a new thread?

More details would help. How sure are you of the composition of the alloys you're trying to combine? Did you measure the temp of the melt? Do you have a picture or can you describe the result?

ETA: hiccup edit

[M-Tecs]

I have 90 pounds of Linotype that doesn’t blend with pure lead. HELP?

What type of problems are you having? Something is amiss. Pure Lead melts at 621 degrees and melts LinoType 462 degrees. If the LinoType is not melting it's not LinoType.

[Steve Steven]

lign,
In reply to your question, I was trying to melt lead lumps and antimony lumps at the same time in a stainless cooking pot. when the antimony got to a hot (lead was already melted) temperature, LARGE clouds of white smoke evolved, I shut down the torch immediately and rethought what I was doing. It seemed to me oxygen in the air was reacting with the hot antimony, if I could keep the air from the antimony I could stop the white smoke from evolving, thus the tight fitting insulation plug (I used 1200deg steam pipe insulation, a white, fiber reinforced product) which worked well. The resulting liquid I poured into a angle mold, I broke up the resulting string into pieces to add when necessary. Note the white smoke deposited all around the area, I don't know if it is dangerous.

Steve

[LAGS]

The white smoke from Antimony and the white dust is Toxic and should not be inhaled or ingested.
I found that if you put chunks of Antimony into melted lead and just kept it melted , the Antimony will dissolve over a long time.
But if you put a torch to the Antimony Chunks or try to heat the Antimony with a torch to melt it to add to the melted lead , you will end up with massive amounts of toxic smoke and white soot.
Just let the Antimony disolve and don't add direct heat to try and speed up the melting of the Antimony.
Also.
If you overheat the Lead , you cause more lead vapor that you can breath in.

[dondiego]

Linotype sure seems like a good deal.

[Cosmic_Charlie]

Wonder why Roto Metals does not offer a custom wheel weight alloy with 2% tin?