Pure Antimony

jordanka16

Active Member
I bought some antimony chunks to try and make my own high hardness alloy, since I have a huge amount of pure lead and lead/tin solder, but not much else. Great for blackpowder but inefficient for anything else. 5 lbs wasn't too expensive, and at 1-3% should last for a long time.

I read about how hard it was to get pure antimony to mix with lead but I think it went pretty smooth. I melted the lead in a small cast iron pan, then added a chunk of antimony and held a torch to it until it full melted, did that over and over until i got a 500 gram bar of 50/50. When liquid it is almost like sand, very grainy.

My next step is to break it up and mix up a clone of wheel weights sans arsenic and see if it behaves the same, before I go and mix up a huge 5lb batch!

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jordanka16

Active Member
The 50/50 ingot I made is very brittle, and the inside looks like a crystal.

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I mixed up a batch, using some lead/tin solder and pure plumbing lead to give me a ratio of approximately 96/1/3 lead tin antimony. Little more tin than wheelweights but good enough for a test.

Worked really well, the antimony ingot chunk mixed right in no problem. I didn't feel like warming up a bullet mold for one pour, so I poured some into a copper pipe cap. The little slug is so hard I can't scratch it with my fingernail, so I would call that a success. Next step is to mix a larger batch and cast some bullets to push hard and see how they perform, but I think it's a winner.

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hrpenley

Active Member
Your much better off if you keep the lead antimony mix at around 70/30, (70%lead, 30% antimony) if not you will get very bad seperation of the metals and it will not mix the way you want it to. I melted the antomony first then added the lead to reach the 70/30 my smelter is hot enough to get the antomony to a nice fluid state and stir stir stir....
 

CWLONGSHOT

Well-Known Member
Your much better off if you keep the lead antimony mix at around 70/30, (70%lead, 30% antimony) if not you will get very bad seperation of the metals and it will not mix the way you want it to. I melted the antomony first then added the lead to reach the 70/30 my smelter is hot enough to get the antomony to a nice fluid state and stir stir stir....
That sounds like Roto Metals SUPER HARD.
 

hrpenley

Active Member
What is the goal?
To make a standard harndess boosting alloy that can harden soft lead and is still meltable with a standard casting pot, given the amount of work to make your own Superhard its cheeper for most people to buy it from Rotometals. I like to play with hot metal so I choose to make my own.
 

jordanka16

Active Member
What is the goal?
I already have lots of tin, and antimony is not too expensive. So this is a simple and cheap way to harden up pure lead, which I also have a lot of.

I'm thinking with this new info I might make up a 40/30/30 alloy, since 3% of each seems to be ideal for most applications.
 

Bret4207

At the casting bench in the sky. RIP Bret.
Reading your posts above, it sounds to me like you've done the leg work in exhausting other avenues to get your higher pressure loads to shoot? I'm not knocking you, just asking if you jumped right to Bhn being the key factor or if you worked the other angles too? I agree completely there is a point where higher Bhn is a benefit, I've just seen way too many people bypass all the other parts of the mixture and just concentrate on a a relative number. Did that myself for a few years before the light came on. Bhn is just another component of dynamic fit.
 

hrpenley

Active Member
No, BHN table is just to give a standard pressure/hardness range (its an easy to find table) for someone just getting into alloying, the same BHN can be reached several different ways depending on the % of each metal used. 2 slugs with the same BHN can be very different in toughness and also perform very differently with the same powder charge. Given the questions I answered as simply as I could, since I have no idea of how much experance any individual has. I can go much deeper into the chemistry of the alloys as can several others on the board, the more direct the question the more precise the question can be answered.....