Lead Hardness Testing

[Zbench]

All,

One of the good things about being on vacation is to think of new and exciting ways to do stuff. I got home yesterday and tested some lead ingot based on the test method used by LASC in their work evaluating various test methods. I ran across the article based on the comments in another thread.

You can see the result here: http://leadandbrass.com/hardtest/hardness.html

I was pretty pleased with the result. Practically, it means I have a very accurate way (lab strength) to test lead alloy hardness that is both precise and accurate.

I'm excited about some of the future uses of this approach such as the real quantifiable impact of water quenching and hardening curves for various alloys (not to mention ordinary hardness testing).

I'd welcome your comments!

Pete

[sqlbullet]

In the article you mention lab analysis of the lead to determine composition. Could you point me to some information on where I could send a sample to have that done, and what the cost is?

I have a large quantity of lead, that I can cast fine bullets with, but would like to have more definitive information regarding composition.

Any information you can provide would be great.

Thanks.

[Zbench]

I'm not aware of any lab that will do this for you for analysis sake alone. The place we have process our range scrap into #2 does it to confirm the starting composition so they know what to add to make alloy to our specs.

Having said that, depending on where you live, some scrap yards have X Ray type guns which they point at a sample and will give a detailed analysis. The results of the gun are not as accurate as a chemical assay, but they are pretty close. You might look in the yellow pages for such a place in your area and take a couple bars and see what they can do. I'd approach it from the standpoint of checking the content and getting a quote for some you might want to sell, rather than just showing up and asking for a free analysis.

Pete

[nodda duma]

Zbench,

Your method is exactly the same as that used in the optics industry to measure hardness of polishing pitch. The only difference is the amount of force applied. The typical weight for measuring pitch is 1 or 2 kg. The indenter is tapered at 14 degrees with a tip diameter of .040". The indenter is allowed to sink into the pitch for 4-5 minutes, and the depth is measured via dial indicator just as you describe. At that point the work is done. You then adjust the softness of the pitch you are mixing by adding softer or harder pitches (much like mixing in tin or linotype to harden up lead alloy). You are aiming to get particular ranges of indenter sink depth, depending on the size of the lens you are trying to polish out (the depths vs. pitch hardness being determined experimentally many, many moons ago).

-Jason

[sqlbullet]

Thanks for the info. I will check locally to see what I can find.

[Zbench]

The main thing to remember is to make the sample you take for analysis as representative as you can. Don't just melt down 20 pounds and assume that all your lead is that composition. If you can smelt a large amount and unify it in one batch and then take several ingots from that, you'll have better results.

Pete