Bullet Casting Question - Antimony

5% antimony doesn't shift the alloy melt point up significantly, since the antimony is in solution with the lead. Antinomy's high melt point does make it difficult to add pure antimony at home, which is why most home casters use pre-alloyed antimony instead.

I buy the 30%-70% antimony - lead and have no problem melting it. I can't give a detailed explanation either but the melting point will change depending on the alloy. I miscalculated and used way to much tin once, very low melt point and something like 360 grain bullets from a 405 grain mold.

http://castboolits.gunloads.com/showthread.php?138362-Why-Car-Batteries-Are-Dangerous

The gases produced are lethal even in small, UNDETECTABLE levels. Don't do it!

Also the Lyman recipe is heavy on the tin, you only NEED 2%, over 2% is wasted, adds expense to the alloy.

snuffy said:

The gases produced are lethal even in small, UNDETECTABLE levels. Don't do it!

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Health risks aside, there are easier sources of lead.

Antimony will "dissolve" in lead at 630 degrees it just takes time and some stirring. Once alloyed with lead, Antimony (and Tin) lowers the melting temperature of the alloy compared to pure lead. A really good cast bullet alloy is 6% Antimony, 2% tin and 92% lead. If this alloy has even 1/4% Arsenic (chilled shot will provide) it can be water dropped quenched or oven hardened and quenched for extremely hard cast bullets for high velocity/pressure. Depending on how you cool the castings, you can vary the hardness from about BHN12 to as much as 28-32 BHN.

Best bet is to get some chilled shot to add in, some wheel weights work just fine as is, or buy from someone like roto-metals pre alloyed lead and mix in with yours. Please do not even consider batteries for lead, it is just not worth it. I don’t pretend to understand the science of it, but I do know how to take certified metals of known composition and mix them to get what I want. Buying Lyman #2 would be the easiest way to go if that is your goal.

Curator said:

Antimony will "dissolve" in lead at 630 degrees i

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Melts at 630C (centigrade) is what i found. Have you melted pure Antimony? I have not, so just asking.

Rotometeals sells it blended with lead, so it melts at a lower temperature.

You can download a free alloy calculator here http://castboolits.gunloads.com/showthread.php?105952-Lead-alloy-calculators it works on Excel or OpenOffice calc. etc. and you can get a general idea of what your mixed alloy will yield. As an example Magnum 7 or 8.5 lead shot has 6% antimony, 1.25% arsenic and about 92% lead if you mix 5 lbs. of that with 15 lbs. of pure lead you will get an as cast bullet BHN of around 10.

Here is what the spreadsheet looks like when open. The area in Yellow is where you punch in you weights, hit enter and the presumed BHN is calculated at the bottom.

The antimony doesn't need to melt to go in solution with lead. It simply dissolves.

Think of it as sugar put into water. Sugar melts at a much higher temp than water (ice), but one needn't get the water to the melting point of sugar to get a solution.

The sugar just dissolves in the water. As does antimony in liquid lead.

You might read a little more about tin lead and tin lead antimony alloys.

63 tin 37 lead melts at a lower temp than either metal alone. That is called the eutectic alloy.

For lead tin and antimony you have 84/4/12 which is linotype metal.

Hooda Thunkit said:

The antimony doesn't need to melt to go in solution with lead. It simply dissolves.

Think of it as sugar put into water. Sugar melts at a much higher temp than water (ice), but one needn't get the water to the melting point of sugar to get a solution.

The sugar just dissolves in the water. As does antimony in liquid lead.

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I haven't got into making my own boolits but this seems like the best simple explination.

Chapter 3 will explain in some detail pertaining to antimony in lead along with some other useful information. You can download the PDF free for future referance.
http://www.lasc.us/Fryxell_Book_Contents.htm