Properties of Lead and Lead Antimony Alloys

[longbow]

Well, for the few of you that knew, I have had this info for a while and finally got to transcribing it.

I was told by the company that I could not reproduce it in any manner but could transcribe portions as long as the source was given.

So, I picked out the best info that would be of use to boolit casters and typed away for a bit.

Enjoy!

Longbow

[montana_charlie]

LB,
Is there anything in there on lead/tin alloys?
CM

[longbow]

CM:

No, these are all the tables that were of any use and are either pure lead or lead/antimony alloys.

There might be some info on lead/tin alloys in the Research library though. I'll see what I can find when I get time.

Longbow

[Harry O]

Very interesting. I intend to spend some time looking at the details, but for a start, I compared the second page you posted with the results of my own experiments. I have a webpage that shows how I figure out the Bhn of the finished mix (lead, tin, and antimony). Part of it (about halfway down on the webpage), shows a chart of the hardness of an antimony/lead mix. This chart was entirely the result of my own experiments. I was not able to find what you have posted on the second page so I mixed up a bunch of different mixtures and tested them (back when I had access to an industrial Bhn tester -- actually, three of them).

In comparing the two charts, we are within 0.8Bhn in the very low percentages, then less than 0.5Bhn for the midranges (in fact several are within 0.2 and 0.3Bhn). We start to diverge about 12% or 13% and are up to 1.5Bhn off at 14% antimony. This chart is important because, I can then add in the tin and get a Bhn for a lead/tin/antimony mixture that has been pretty darned accurate.

Here it is: http://www.sixshootercommunity.com/articles/harry_o/cast_bullet_hardness.html

I am happy to see this because when I first posted the webpage here (some time ago), two people on this website said that I did not know what I was talking about. And they said it several times and in several ways. I finally said I will not answer either one of them and will not enter a thread they start. All I know is what is in that webpage works for me.

I have found out a few additional things since the webpage was posted. I did all my testing with 200gr bullets that were air dropped into a towel. I have since found out that 100gr bullets are approx 0.8 to 1.0Bhn higher than a 200gr bullet with the same mix (also air dropped). A 400gr bullet is approx 0.5 to 0.8Bhn lower than a 200gr bullet with the same mix.

Thank you very much for posting this.

[Harry O]

A couple of more comments (after looking at the data a little longer). The lead they are using is 99.73% pure and measures 4.0Bhn. That is different from mine. It is more pure and softer.

I used "pure" plumbers lead when I first started. I don't know how pure that is. It never tested below 4.5Bhn. The most common tests were 4.7 to 4.8Bhn. Later, I managed to get 1,200lbs of roofing lead that was made from 90 to 120 years ago. When I tested it, it ran from 4.7 to 5.0Bhn. The most common tests were 4.9Bhn. I rounded it off to 5.0 for the purpose of my list. There is no doubt that there were some impuritites in that lead.

Interestingly, if I add 1.0Bhn (the difference between 4.0 and 5.0) to all the figures on the chart you posted, it is further from my list than comparing the two of them directly. I am not at all sure what that means.

Also, the chart shows that lead/antimony strength peaks at 10% and goes downhill from there. I think that might have something to do with the brittleness. I am guessing that the extra strength from more antimony doesn't compensate for the decreased elongation above 10%. I do know that the affect of antimony tapers off (plateaus) at high percentages of antimony. I also know that I have had some high antimony cast bullets break at the crimp before. A fairly clean break, like a wadcutter. The problem is that high antimony (harder bullets) goes hand-in-hand with a heavy crimp (for high-velocity loads).

My own rule (and I know that this is different from some others here) is that I try to get more tin than antimony in my mixtures. 1-1/2 to 2 times more tin than antimony makes it fairly easy to cast with. Using less antimony than tin makes even good moulds difficult to cast with -- at least I have that problem.

[longbow]

Harry O:

I will see if I can find any more info in the research library. The company is over 100 years old and very large lead producer. They have a long history of smelting and refining lead, zinc, bismuth, indium, gold, silver, and a host of other metals.

I really don't put any of this info to work other than the oven heat treating. For the most part I use straight wheelweights, wheelweight/lead mix or range scrap for my casting. If my moulds don't fill out I cast hotter. Crude I know, but it has worked for me.

The sad thing is that I work for a lead smelter and am surrounded by hundreds of thousands of pounds of lead and alloys every day but I cannot buy lead from where I work!

Anyway, If I find anything else of interest I will let you know.

Longbow

[randyrat]

I see, looking at the second table, why 4% antimony is the magic # for WWs.

[Dannix]

Links broken or content removed longbow?

[lwknight]

Links broken or content removed longbow?

Yea, whats up with that?

[geargnasher]

Where did you guys dig up this thread?

Gear

[Dannix]

The Cast Boolits site. Maybe you're heard of it?
:kidding:


To be honest, I forget. I was gold mining via search (I find some great info that way) and then realized this one was missing its core content and was edited just a few months ago.

[longbow]

I guess it was a casualty of having to delete some attachments.

Since space on the site is limited it would likely be best if I e-mailed the info to anyone interested.

If you want a copy, send me a PM with your e-mail address and I will send you your very own copy.

Longbow

[Dannix]

PM en route. I should be able to post it here too for you.

[Dannix]

Attached. Thanks longbow

[montana_charlie]

I don't know if HarryO has returned to this thread since it's resurrection, but I read his article, and liked it.
The one thing I have trouble with is where he said, " In addition, Microsoft Excel can be programmed to instantly dump out the results for any combination you put in. In that case, there are no calculations necessary."

I have used a number of those Excel spreadsheets, and can't get them to calculate accurate results.

You can (for instance) plug in the quantities of lead and tin necessary to produce 20-1 alloy, and the hardness number returned by the spreadsheet is roughly three BHN higher than the actual hardness of that alloy.

If you simplify your input to merely find the hardness of ten pounds of pure lead (entering zeros in the other spaces) you get 8.6 BHN. We all know that's a lie.

If the calculation for pure lead is wrong, I don't see how any other results could be trustworthy.

CM

[Dannix]

Harry's still around. I'm going to send him a PM so he knows there's a question here for him.

[Harry O]

> I have used a number of those Excel spreadsheets, and can't get them to calculate accurate results.

Thanks for pinging me. Excel spreadsheets will calculate whatever you put in. I programmed mine to calculate the antimony, tin, and lead quantities of whatever was put in the pot (such as WW; 50-50, 60-40, 63-37, 95-5 solder, monotype, or linotype) and give me the total percentage of antimony and tin in the mixture.

From the total amount, I use the chart I came up with to calculate the probable Bhn of such a mix. Then I mix it up, cast, and test it with a Lee Bhn tester afterward. The calculated Bhn and the measured Bhn are rarely identical, but they are close. The tests are usually within one Bhn higher or lower than the calculated. That is close enough for what I need to do.

One thing should be kept in mind. There are a LOT more reasons for variation in the tested Bhn other than the mixture alone. For example, I once used one pot to cast three different bullets. All were cast from exactly the same mixture. One was about 100gr, one about 200 gr and one about 300gr ( this is from memory, I would have to check my records at home for specifics). All were air dropped onto a towel. The 100gr one was close to one Bhn higher (harder) than what was calculated. The 200gr was very close to what was calculated. The 300gr one was between 1/2 and 3/4 Bhn lower (softer) than what was calculated.

That makes sense for a couple of reasons. When I cast up a bunch or mixtures to individually test and then used the results to create my chart, I was using a 185gr bullet. So that was what the chart was based on. Also, the smaller bullet would cool quicker and be harder (somewhat like dropping it into water). The larger bullet would cool slower, so it would be softer. Of course, if you actually do drop them into water, the Bhn's would be completely different.

In other words, the chart I use gets me close. That is all I need. I don't believe that there is anything such as "exact" when it comes to Bhn and casting. I am not pushing my chart for anyone else to use. You can use it or not use it. It is entirely up to you. In either case, I will continue to use it myself.