Ultra soft lead?

[montana_charlie]

I sure need the 'combined mind' to help with this!

I contacted an eBay seller about some lead he had for sale. As usual, I questioned him closely about the source of his metal, trying to decide (for myself) how 'pure' it might be. After a couple of back and forth messages, it became apparent he was using a Lee hardness tester, but was not able to get a solid BHN for this metal

So, I sent him one of those charts that extends the Lee information downward...to reach BHN 5.

He still could not find a number that matched the reading in his microscope...said reading being clear off the imprinted scale.

Obviously, this poor, benighted, lead salesman need my help, so I got a sample from him.

Now I am in the same boat he is in!

The dimple in this sample is bigger than the microscope scale, and you can bet I operated the tool correctly. Using a dial caliper, the dimple diameter measures .133".

I have tried extrapolating the Lee chart down to this size, but keep getting a BHN around 3. I could use the help of a math wizard to check that out.

Then, there is the fundamental question...
I know that BHN 5 is generally recognized as correct for 'pure' lead, but what is the number for (say) 'virgin lead'?

That is the only term I have ever heard of which might explain metal this soft.
CM

[ktw]

I am not sure that the Lee tester is sufficiently sensitive with lead in that softness range. I suspect this is why the Lee supplied table does not extend down into that range.

I also use a Lee tester with the extended table. I occasionally get blelow-the-scale-soft readings with lead I expected to be near 5 bhn. I have been calling it good enough and throwing it in the "pure" lead pile.

-ktw

[montana_charlie]

Well, I would certainly call it 'good enough', too.
Has anybody ever seen BHN 4 used for lead? I seem to remember seeing it...just can't remember in what context.
CM

[Bass Ackward]

Well, I would certainly call it 'good enough', too.
Has anybody ever seen BHN 4 used for lead? I seem to remember seeing it...just can't remember in what context.
CM


4 BHN?

Silly Puddy or one of my wifes cakes.

[MT Gianni]

Charlie, Send me a sample and see what Cabintree [Gussy's] says. Gianni

[454PB]

I think you need bigger balls Charlie. Seems to me the Lee tester was designed to fit a BHN parameter around what the average boolit caster uses. If the tester had a larger ball, it would be accurate at the low end, rather than at the high end. I have some pure lead, which I use it to dilute linotype. I found the same results you got, the test dimple is too large to give an accurate reading. For my purposes, it tells me enough. It would be interesting to see some comparison testing with other types of testers.

[shotstring]

Last time I talked with Gus at Cabintree, if I remember correctly, he claimed that it is more difficult to measure the hardness of really soft lead, due to any slight variation in the procedure will easily give different readings.

[ANeat]

As lead gets worked it softens. If its something that has been rolled out or worked in one way or another it will check softer. To get an accurate reading melt some and cast a fresh ingot. Check the hardness of that.

[montana_charlie]

To get an accurate reading melt some and cast a fresh ingot. Check the hardness of that.
THAT sounds like a good idea. Thanks!
CM