lead hardness ?

[roysha]

I suppose this is a rather dumb question but, as usual, I'm a bit confused. The question is in regard to lead casting alloys using the three usual metals, Pb, Sn, Sb.

Question: Within the capabilities of the average home owned lead hardness tester, does a specific percentage alloy result in a hardness that only that alloy can have, or can there be several combinations of metals that will yield the same reading?

That question is leading up to more questions if the answer is yes, more than one alloy can give the same reading. However, if the answer is no, then the subject is closed for my purposes.

[PJEagle]

In my experience, there can be different combinations of the three usual metals that will give the same hardness. If you download the alloy calculator and play with it for a while you can see what I mean.

[Rickf1985]

Simple answer, Yes. You can have more tin and less antimony or vice versa and get the same hardness. BUT, it takes a lot more tin to get there or a lot less antimony. Like was said, download the calculator and play with it a bit and you will learn. Learning how to use it can be a chore but once you figure it out it is easy.

[243winxb]

Yes. More then 1.

[JonB_in_Glencoe]

yes.

Be sure to read this chapter.

http://www.lasc.us/Fryxell_Book_Chap...Metallurgy.htm

[PBaholic]

The question is in regard to lead casting alloys using the three usual metals, Pb, Sn, Sb. Question: Within the capabilities of the average home owned lead hardness tester, does a specific percentage alloy result in a hardness that only that alloy can have, or can there be several combinations of metals that will yield the same reading?

Yes, there are many combinations that can have the same hardness, within the range that is possible:
Pb = BHN 4-5
Pb & Sn = BHN 5-17
Pb & Sb = BHN 5-50+
PB & Sn & Sb = BHN 5-50+

An alloy hardness is NOT absolute, and varies. You can in crease the hardness of alloys (not pure Pb) by cooling it quickly. Hardness of an alloy varies over time, generally increasing, but some alloys increase in hardness, then decrease as more time passes.

Pb & Sn is fairly EZ to graph, so I've included what final hardness these alloys will have depending on their mix.

[bangerjim]

Yes, you can get the same hardness with different combos of Pb, Sn, Sb. Like said above, get that alloy calc from on here and use it.

I have a CABINE-style tester that I checked/calibrated against a NIST hardness system and I still rely on my mixing to get the hardness I want....
normally 9-12 will do it + PC for 95% of what I cast & shoot.

And remember - - - - - alloys can/will change in hardness with age. Nothing is "for sure" in this life................except death & taxes.

banger

[Larry Gibson]

Not sure where Lyman came up with a BHN of "5" for pure lead?

The National Institute for Standards lists pure lead as having a BHN of "7". In testing numerous different samples of "certified" pure lead I have found them all to be "7". I have yet to find any that are actually "5". That is with my Lee tester in a microscope stand which makes testing as accurate as the Lee can test.

Anyone else actually tested certified pure lead?

[bangerjim]

As I said above, I ran my CABINE-style tester against an NIST certified tester in a lab with known samples and it is NOW dead on after a bit of re-calibration.

Now I get 6.7-7 when I test dead pure lead. Same as the NIST tester.

I question several of the "facts" Lyman has published and have become gospel to casters/loaders over the generation.