Harder Alloy

steve4102

New member
What is the simplest way to increase the BHN of my alloy? I use straight WW and I would like to add to the WW mix to make my bullets a little harder.

I know about heat treating and water dropping, now I want to know about adding to the Mix.

Thanks
 
The simple way is to cast those wheel weights fairly hot, open the mould as soon as the sprue sets & drop them directly into cold water, the colder the better.
 
linotype works.
Linotype is not available or inexpensive enough to use as a straight bullet alloy in many areas of the country. In some cases, it may as well be "unobtainium". An alternative, is to add up to 2% Tin, and "Chilled lead shot" (contains Arsenic), to the melt and heat-treat by either water-dropping or oven hardening.
 
dehermit is right about lino, checking on ebay can give you a scare. I still have a coupla bars left from when I was stocking up in the eighties. I have personally gone to oven heating my WW metal. I don't have a hardness tester, but bullets quenched after an hour at 450 are really hard.
 
Several good options already mentioned. About the easiest is adding in shot.

Either chilled or magnum will work depending on what you have readily available. Best course when using it in however, is to smelt it up separately adding in a little at a time. Make sure you have a spoon that you can mash it with as well, as some of the time it will develop somewhat of a skin which is harder and the lead inside of it can't get out.

I used it quite a bit to make up fishing weights years ago and found that depending on which brand, hardness, or even age, some would readily melt and some had to be mashed. What you DON'T want is to have most of it melt and some of it stay in pellet form. That will make things miserable. Just be sure to mash as you go and if it is floating mash it against the sides of your pot. Again only do small batches at first to see how it goes before simply dumping in 5# or so.

After smelting some of the shot into ingots, only blend up a small batch at a time with your WW's and weigh out exactly what your mixing so you can replicate it the next time. Personally I wouldn't make it up in batches over about 5#. Also remember that it doesn't quite do a linear alloy either, meaning adding say 1" of shot alloy into 5# of WW's isn't going to be as hard as adding in 2# of shot into 10# of WW's. The arsenic will do more as it is added in and you might end up with harder than you actually want.

Also you might want to check out the latest Alloy Calculator over on Castboolits in the Lead and Alloy section. The older version I have has several different shot type listed on it, and you can somewhat calculate what you have, and what you will end up with, within a very usable degree of accuracy.

Hope this helps.
 
You can get tin in the form of pewter. Keep your eyes open at garage sales and thrift stores for old pewter items like tankards, pic frames, candle holders, etc.
make sure it says pewter on it somewhere.
 
Antimony is the metal used to harden lead. In a casters situation perhaps a little Linotype or Babbiting material is easier to come by. Doesn't take much of either to increase CO-W/W lead BHN factor.
 
What about monotype? Similar composition to linotype?

Similar but NOT the same. Monotype was used for individual letters for printing a LOT of paper, like books and posters. Linotype was used to print newspapers, and was re-melted for the next days paper. It did not have to last long. Also, it was cast in long lines of letters for each line in a newspaper.

Tin will only harden lead very little. It's main function is the wetting of the lead, making it cast more easily into the complex shapes of a boolit. Another thing it does is to give the lead strength. It's also necessary for antimony to stay in solution with the lead. Too little tin, you'll see crystals of antimony surrounded with soft lead.

^^^^^The above is important IF you were to send to Rotometals for the super hard alloy. Added to pure lead in an attempt to harden it would result in the antimony crystals showing up surrounded by pure lead. You would need a minimum of 4% tin added to that mix to have good hard boolits. Addition of some chilled shot will give some arsenic, which will allow water dropping to heat-treat the boolits. You CAN get hardER boolits without arsenic, but not as much. Relax, if you're using wheel weights, it's almost certain there's some arsenic already present.
 
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