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Thread: Toughness Of Lead-tin-antimony Alloys

  1. #61
    Boolit Master
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    The subject of whether we want bullets to obturate or not has been discussed at length in several other threads. My recommendation is that you reopen one that has already discussed Richard Lee's position on the matter if you have reason to debate the matter further than it already has been.

  2. #62
    Boolit Grand Master leftiye's Avatar
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    243, You'll want to study this further. There are other theories out there, including those that say that the plastic limits of lead being surpassed are even beneficial. There are many reloaders here who completely eclipse the 1422 X BHN rule and still get fine accuracy in their high velocity loads, even when using softer alloys.

    There are those, as you have seen here in this thread, who try to make boolits that expand, and loads with those boolits with proportional velocities for hunting purposes. This is where the issues of boolit toughness is important. Hardness alone is not a sufficient indicator of toughness in an alloy. It is in the expansion of a boolit upon impact with an animal, without the boolit disintegrating that toughness is evidenced.
    We need somebody/something to keep the government (cops and bureaucrats too) HONEST (by non government oversight).

    Every "freedom" (latitude) given to government is a loophole in the rule of law. Every loophole in the rule of law is another hole in our freedom. When they even obey the law that is. Too often government seems to feel itself above the law.

    We forgot to take out the trash in 2012, but 2016 was a charm! YESSS!

  3. #63
    Boolit Grand Master

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    I don't know how I missed this thread. Very good stuff here. I'll have to take some time and go through again more thoroughly.

    I'll add a link to some info I posted on the Cast Boolit forum about a month ago. Some may have this info and some may not but it fits in with the testing being done here and may be useful.

    http://castboolits.gunloads.com/showthread.php?t=48048

    Longbow

  4. #64
    Boolit Bub
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    The atomic weight of tin is 119.
    The atomic weight of bismuth is 209.
    If the solution of Sn/Bi is 1/1 the weight of tin should be more like 4/7. instead of 1/1 by weight.
    Can someone explain. Perhaps 2 tin atom is needed for each bismuth atom to create the alloy crystal latices in lead?

  5. #65
    Boolit Master
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    I'm not sure I understand your point yet techlava. This thread is about lead-tin-antimony alloys, and for those alloys in the percentage-range we are concerned with, the key point is the ratio of tin to antimony. The highest toughness seems to occur when tin and antimony are in the ratio that enables them to combine into the compound SbSn: that is, one atom of antimony to one atom of tin. The atomic weights of tin and antimony are 118 and 121, which is very close to the same, so in practice the toughest alloys have approximately equal percentages of tin and antimony when measured by weight. In other words, what my experiments seem to have demonstrated is that crystals of SbSn contribute more toughness to lead-tin-antimony alloys than any of the other crystals, or the lead matrix alone. It seems unsurprising that this would be the case; IIRC Weaver found more than 70 years ago that SbSn is very scratch-resistant compared with other crystals found in lead-tin-antimony alloys, though it is not harder than some of the other crystals. What is slightly surprising, and very convenient, is that the toughness contributed by the SbSn crystals seems to respond very positively to moderate heat-treatment.

    Perhaps you were following a thread on bismuth alloys and accidentally posted to the wrong thread?

  6. #66
    Boolit Master
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    Excellent thread! Thanks for sharing.

    Any Cu alloy testing on your horizons, grumpy one? Cu has been coming up around here now and again.

  7. #67
    Boolit Master
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    Quote Originally Posted by Dannix View Post
    Excellent thread! Thanks for sharing.

    Any Cu alloy testing on your horizons, grumpy one? Cu has been coming up around here now and again.
    Dannix, my whole process here has been put on permanent hold because of problems getting analysis done at a sensible price. A local scrap metal business had agreed to run an XRay Fluorescence scanner over my samples for free, so I would know what I had tested, but after doing one batch of half a dozen samples for me, their head office in Sydney decided to stop rotating the scanner to the Melbourne office. By then I had another ten samples waiting for analysis, having completed a "refinement" series of tests aimed at pinning down the optimum-toughness lead-tin-antimony alloy fairly precisely. One year later, the position has not changed. No other scrap dealer in Melbourne who has a scanner, is prepared to help. (There appear to be only three such dealers in this city of 4 million people.) I'm completely unwilling to buy lab analyses of ten samples, so I put the whole matter aside. My case of samples is stored in my cellar.

    Adding copper to the investigation is something felix suggested way back at the beginning, and is certainly of interest provided we could do it in the context of first having a fairly good handle on the lead-tin-antimony picture, and knowing we could get samples of the copper-bearing alloys analyzed.

  8. #68
    Boolit Master
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    Bummer. Hopefully something will open up again.

  9. #69
    Boolit Mold
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    to:muddy creek SAm M. G CAST again. I need lead, any shape ,size or what ever, vials, containers, ingots or cores. Please e-mail me price of two boxes, 126-136 lbs. I also need your mailing adress and I will get M.O.in mail ASAP annandmarvin @cox.net M.G.Webster,5611 Sardis Church Rd. Macon ,Ga. 31216-7041 Many thanks M.G.CAST

  10. #70
    Boolit Buddy
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    Any way to get CU alloyed into this mixture

    Is there any way that powdered or ground copper filings can be alloyed into a lead mixture. afish4570

  11. #71
    Boolit Master
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    Lead melts at 327 degrees C, and copper at 1084 degrees C. Alloying the two is therefore not as simple as mixing metals with similar melting points. This is the same issue that arises when alloying lead with antimony. If you add copper to molten lead, you will end up with your copper powder floating on the surface. You could melt the copper and then add lead, thus obtaining an alloy with a lower melting point. If you gradually added enough lead to get the melting point down far enough, your copper/lead alloy could ultimately be added to a pot of lead. For most people though, if you want to add a tiny amount of copper it would be easier to get some copper-containing scrap lead. Some forms of babbit would be suitable for this.

  12. #72
    Boolit Grand Master leftiye's Avatar
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    Use stranded copper wire (lampcord), cut it up into short (1") pieces, put it on your melted solder a little bit at a time while playing a propane torch on it (don't overdo it or you'll get copper oxide which is hard to mix in), and stirring all the time. Only stir the surface until the copper dissolves, then stir deeper. When you have the copper melted into the solder, then pour it into the melted lead. Werked fer me.

    About 1.6 ounces copper for 10 lbs. to get 1%. For 10% tin in 10 lbs alloy it's about an lb. of tin. If you have 60/40 solder 1lb of tin means about 1.6 lbs of solder. 10% tin and 1% copper is BHN 18.
    Last edited by leftiye; 02-12-2012 at 11:08 PM.
    We need somebody/something to keep the government (cops and bureaucrats too) HONEST (by non government oversight).

    Every "freedom" (latitude) given to government is a loophole in the rule of law. Every loophole in the rule of law is another hole in our freedom. When they even obey the law that is. Too often government seems to feel itself above the law.

    We forgot to take out the trash in 2012, but 2016 was a charm! YESSS!

  13. #73
    Boolit Grand Master popper's Avatar
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    Sn likes Sn and will come out of SnSb over time. It also forms pure Sn dendrites which are weak.
    Think of a super-saturated solution that 'settles' out to a saturated solution. Those molecules 'float' around in the 'solid' - age hardening, then age softening. Arsenic, sulfur and copper mess up the lattice and make the globs smaller, thus the alloy is harder. From my investigation, SnSb hardness is linear, maxing at 1:1. Adding transitional metals (cu) and the hardness is non-linear. With Pb mohr hardness at 1.5, adding Sn,Sb,As, S gets an alloy of mohr 4.5. Diamond is 10 mohr. The problem is getting the alloy stable when cooling(quenching).
    Last edited by popper; 04-17-2012 at 03:14 PM.

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