cast alloy ouestion

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coyoteshooter

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so i experimented with a lot or batch of pure lead and added a little pewter and lino ....checked the hardness .after 12 hours then added more lino..waited 12 hours tested bn with lee tester....added more lino....waited 12 hrs..tested added...waited ..tested then i finally got to the bn for lyman #2...i mean rite on according to the book and the tester////////my question is this.......after 24 hrs and the mix tests lyman#2 hardness........does it matter how i got to that mix .....ie the components i listed or is the mix not the same in use as say a lyman #2 mix one could make using one of the book formulas listed in lyman infomation sheets....i made 45 lbs by the time i was happy with the bn......just a question thanks for pondering....don
 
Short answer is no.

Composition affects, brittleness, elasticity, etc

Also lead aloys soften over time. Type of aloy affects how fast or slow.

The closer you are to getting tin/antiminy ration to 50/50 the less its an issue.

One must almost take a metalurgy course to learn the real complexities of aloys.

For target shooting, it does not matter.

Even zinc under 3%ish in the mix doesnt mater, it also adds hardness. May have to add a touch more tin to help with fillout


ps. Lead usually gets harder for a period of time before it starts to soften. The softening takes years.

If you have a good tester, you'll find in a month or two it will have goten slightly harder. Test in 2-3 years, it will be softer
 
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Although I no longer do bullet casting, I will go with what yomomma says above - adding tin to pure lead is to make the melt to be "runnier" - that helps to fill out the nooks and cranny's in the mold better - does not usually do much for "hardness" of a cast bullet, although it might, while making the bullet to be lighter weight. To make it "harder", get some antinomy in there, then do heat treat - heat up to just below melt point - so just very hot cast bullets - then quench cool quickly in cold water - if there was antimony in the alloy, those bullets will become harder - if there was no antinomy in the alloy, that was about a waste of time. There is an alloy that I found described on Internet - BHN is 28 - was like 19% antinomy, some tin and 70-some percent lead.

I think was an article in Handloader magazine to describe that heat-quench cycle - get a metal pail - like some jam or lard used to come in - perhaps held 5 or 10 litres - poke numerous holes in sides and bottom - put softer bullets in there and about an hour in kitchen oven at 400 or 425 degrees F - so MUCH hotter than boiling water. Then get like 5 gallon (25 liter) pail and almost fill with cold tap water - use oven mitt to grab handle on that small pail of bullets in oven and transfer into the cold water pail. All those holes you poked were to allow water to easily and readily get in there. Idea is to make those bullets get cold quickly - not so they would cool slowly - so likely helps to swish it around in the cold water.

I think you will find that linotype alloy has about 4% tin, 12% antinomy and the rest is mostly lead, plus contaminents. Pewter is mostly tin - later stuff might have had a bit of antinomy in it. Adding that linotype alloy to pure lead was getting some antimony in there - up to you about the ratio, etc. - but it is the antinomy in the alloy that allows it to respond to a "heat and quench" cycle, to become harder BHN.

I think it was from Western Metals that I got a bag of one pound of pure antinomy - so was like chunks of rock and some like "sand" - as I understood, would weigh out pure lead and antinomy in proportions that you wanted - then melt the lead, then pour in the antinomy crystals - stir and flux to mix it - apparently that got you a lead-antinomy alloy - then to heat /quench treat bullets that were made from that, to make hard. I had recently read that as little as 0.5% antinomy would result in an increase in hardness that you could measure on a Brinnell scale - I do not know, but I presume that was AFTER a heat and quench cycle.

I do not know if the heat/quench cycle will affect the elasticity or brittleness of the bullets - someone who has done so will have to say what they experienced. I do not even know how to measure that stuff.
 
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yomomma said:
Short answer is no.

Composition affects, brittleness, elasticity, etc

Also lead aloys soften over time. Type of aloy affects how fast or slow.

The closer you are to getting tin/antiminy ration to 50/50 the less its an issue.

One must almost take a metalurgy course to learn the real complexities of aloys.

For target shooting, it does not matter.

Even zinc under 3%ish in the mix doesnt mater, it also adds hardness. May have to add a touch more tin to help with fillout


ps. Lead usually gets harder for a period of time before it starts to soften. The softening takes years.

If you have a good tester, you'll find in a month or two it will have goten slightly harder. Test in 2-3 years, it will be softer
Click to expand...

to further my queery ......my notes say im at bn 14.2 not having shot any of this mix would you think they might perform similar to the batch i did a year back...as it was also in the 15 bn range but of a different recipe....time will tell but for now this is my question....i know you lads do not have a crystal ball but...........thanks don
 
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