This topic contains 18 replies, has 1 voice, and was last updated by  Goodsteel 2 years, 6 months ago.

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  • #30903
     lar45 
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    I received some lead alloy in a trade recently and had it analyzed for it’s content. It came back with quite abit of copper in the mix and I’m wondering if this is going to cause any problems when casting boolits.
    The first was a bunch of foundry type that came in at:
    Lead 48.7%
    Antimony 26.4%
    Tin 16.32%
    Copper 8.49%

    The second was some tin/lead ingots:
    Tin 85%
    Lead 1.6%
    Copper 5.5%
    Antimony 3.5%
    Iron 1.68% – probably rust from an ingot mold?

    Any thoughts on the copper in the mix and being mixed with wheel weights?

  • #30906
     Sgt. Mike 
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    Popper usually looks for ways to add the copper to his alloy.
    sounds like good source of alloying with other lead sources.

  • #30909
     Goodsteel 
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    There is very sketchy information posted on copper enhanced alloys. I asked one of the proponents of that method to please come here and post, but he declined stating he was done trying to convince people it’s a viable method (certain other forums have an absolute gift for discouraging original thought).
    I have read that the copper content is limited by the tin content because the tin is required to keep the copper solved in the alloy. That content in a typical 3-5% tin bullet alloy has been suggested to be about 3% max. (please use these words as a guide only. I’m only paroting what I think I remember reading from those who mess with the stuff a lot. ie: I read it on the internet).

    I have limited experience with copper alloys myself. I tried a 2-3% mix but found my consistency was destroyed and the bullets came out undersized and really rough looking in comparison to one of the three alloys I enjoy using most (House alloy, Lyman #2, Linotype).

    This is something that a very select few people have knowledge of, and I would love to see experiments brought to light concerning these alloys. (I might have to revisit them myself).
    I have suspected that if consistency can be obtained, this might be the key to getting cast over the secondary boundary we ran into in the XCB project of 3000FPS -3100FPS. If these alloys are used in conjunction with slow twist barrels, it might be possible to reach 3500FPS with cast lead, but that is a very big IF.

    I have a similar doping alloy here that consists of tin and copper in very rich proportions that I have been holding back in case I ever wanted to get back into this.

  • #30913
     Harter 
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    Like Tim I read it on the net…….. So grain of salt and all that.

    My search was for mailability at the desired speeds because in some circles I step on toes because of my single minded goal of a clean harvest .
    What I gathered was that in typical alloys 3% is the upper limit until you get into babit alloys . The copper content is generally believed to make an alloy tougher for the launch while allowing a softer BHN for expansion while tending to shed less weight .

    If I look at it like connecting rods in an engine pure lead is like aluminum while lino is more like a steel rod . High copper alloy is more like a titanium rod . If the aluminum rod keeps the same dimensions as steel odds are good that they will splatter shortly after full power is reached so they are generally of greater dimensions , big slow fat bullets. Steel rods are the old skool standard/stand by for smallest dimension go fast but they aren’t particularly flexible or adjustable but they are reliably accurate and work even in high performance outside the normal standards , like lino even a mild impact will cause a breakup failure .
    ​​​​​The titanium rod weighs like an aluminum rod , not quite pure lead but very close to ww, they will flex a lot and and often survive a catastrophic failure , the copper and tin keep the lead together for that unanticipated short shot on the 30 point buck but still a viable 250 yd bullet that will nominally expand .

    In my understanding of all that I read about the extreme copper backed alloys, assorted babbitts , would not equal lino ,mono etc groups but didn’t or greatly reduced fragmentation . Somewhere about 1 sentence past all of this it sounded like Charlie Brown’s teacher discussing quantum mechanics.

  • #30914
     sundog 
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    I’ve cast with copper babbit in the alloy. If you get too much you will have a less than desirable fill out. This is a roject Felix and I worked on awhile back. We kept cutting the babbit enriched alloy with COWW until we got a mix that cast well. I still have some of out #5 mix that when added to a pot of COWW casts well. A little bit goes a long way. Too much and the mix will ‘sheet’ when pouring.

  • #30916
     Larry Gibson 
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    I would not add WWs to the 1st batch. Both are already antimony rich, no need to add more. 1st batch I would add 6 parts pure lead to 1 part batch. Then I would add 2% tin to that. That will give you a balanced, antimony tin, alloy between Tim’s house alloy and #2 alloy. The small % of copper left probably won’t have much affect.

    The second batch I would try adding 3% to WW alloy simply to add the tin to the WWs.

    One hundred +/- years ago Ideal Bullet Metal (became Lyman #1 alloy) was the standard alloy. It was 80 lead, 10 tin, 7 antimony and 3 copper. There was considerable shrinkage with that alloy which is why most all Ideal and many Lyman moulds cut with original spec cherries cast .002 – .003 oversize. I’ve found any presence of copper in the alloy will cause additional shrinkage.

    For example; my early made Lyman 311466 will drop bullets at .314 with #2 alloy. With my copper enriched alloy they drop at .311. Same with my CBF GB moulds designed by 45 2.1 for straight COWW alloy. Those drop .313 – 314 with COWW and .311 – .312 with the copper alloy.

    Also the weight variation (bell curve) is much larger, due to the larger shrinkage, than with a good ternary alloy.

    Larry Gibson
    ​

  • #30917
     farmerjim 
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    I like to have .025 % Cu in any alloy I am going to drive fast.

  • #30918
     lar45 
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    Thank you all very much for the info.
    I’ll try adding the heavy tin alloy to WW, and keep on the lookout for some pure lead to mix with the other.

  • #30919
     Rattlesnake Charlie 
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    A google search will produce some research already done.

    “lead copper alloy bullets”
    Gets you a couple of threads on Castboolits, and a couple on lasc.

    “adding copper to lead alloy”
    Gets you several on castboolits and one on lasc.
    This lasc thread is quite useful.
    http://www.lasc.us/FelixBabbitbulletAlloy.htm
    I wonder if it is tied to the project sundog posted about.

  • #30921
     popper 
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    Cut the first with pure – 10:1. Use the second for tin. Pb is a cubic crystal, Cu replaces atoms in the structure so shear force is increased, will only hold 0.3% in solid. Cu alloys with Sb, I’ve shot 3% Sb/2%Cu with BHN >36. Normally I use 3%Sb/0.5%Cu for HV rifle. I don’t add Sn and it casts just fine. Sn-Cu is an inter-metallic that only exists in liquid melt.

  • #30924
     lar45 
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    I added some of the heavy tin mix to a 20# pot of COWW and tried it in the NOE 411-251WFN mold. Straight WW cast a .4136″ and with the tin/copper in it they dropped in size to .4124″. Now to try some in the 405 Win.

  • #30926
     Goodsteel 
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    I’d like to see a small sample of the new alloy Glenn.

  • #30930
     popper 
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    Added tin probably caused that. Cu added tends to make them grow just a tad.

  • #30931
     lar45 
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    How small? a couple bullets, ingot, pound?

  • #30934
     Goodsteel 
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    You know how you pour a puddle on top of the mold after the cavity is filled? That size puddle (about the size of a quarter) poured on clean, cold, uncontaminated steel. You might do the same with the original alloys.

  • #30978
     rockrat 
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    For most of my shooting, I mix up an alloy that proximates WW alloy with 2/10th of a percent of Cu (0.20%). Casts a larger boolit than normal though. I found if I go more than 0.30%, my spout of my bottom pour will freeze up if I pause in casting (I run @710 degrees). If I bump it up to 750 degrees, it doesn’t freeze up, but takes alot longer for the sprue to solidify

  • #30980
     Goodsteel 
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    My experience is limited, but adding Cu to my alloy made the bullets far SMALLER.

  • #30996
     lar45 
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    I’m running at 750F, but I’m having lots of problems with slush on the top of the mix. This was before I added the tin/copper alloy. After adding the tin/copper the bullets fill out much better. I’ve only tried it in a NOE 411-251WFN. With straight COWW I cast for about 1/2 hour and ended up with 5 good bullets. After adding the tin/copper I cast for another 30min and ended up with maybe 20 rejects and a pile of keepers. I think that most of the failure is with the design of the bullet with it’s sharp deep lube grooves. I normally don’t have any problems casting straight COWW.
    I wonder if running the temp higher will get rid of the slush on top?

  • #30999
     Goodsteel 
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    lar45;n10979 wrote: I’m running at 750F, but I’m having lots of problems with slush on the top of the mix. This was before I added the tin/copper alloy. After adding the tin/copper the bullets fill out much better. I’ve only tried it in a NOE 411-251WFN. With straight COWW I cast for about 1/2 hour and ended up with 5 good bullets. After adding the tin/copper I cast for another 30min and ended up with maybe 20 rejects and a pile of keepers. I think that most of the failure is with the design of the bullet with it’s sharp deep lube grooves. I normally don’t have any problems casting straight COWW.
    I wonder if running the temp higher will get rid of the slush on top?

    Been there, Done that.
    Higher temp will not fix it. It needs to be fluxed hard.
    I actually scraped off some of the slush and had it XRF tested thinking I would find trace of zinc or high antimony/tin as some pontificated that it was the alloying metals floating on top. I was surprised to learn that the slush tested exactly like the molten alloy under it!
    I still do not know what causes it, but I do know it can be solved with a chunk of your bullet lube and stirring with a wooden stick. (assuming it’s the same thing I was dealing with).

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