Hardness test 60/40 solder

[stocker]

I've been using solder salvaged from a radiator shop; floor scrapings. The owner claims he uses 60/40 exclusively. In the reclamation I started with 1 and 1/2 , 5 gallon buckets of scrapings. At finish I had a 2 lb coffee can filled with ingots and all the remainder was dirt and filth.

Although the ingots work well, using them in common published proportions with wheel weights to increase tin content of the boolit alloy does not produce a metal of expected hardness, normally being several points softer than might be expected. Neither does it oven harden to an expected level of hardness.

The ingots test at 10.5 on my Cabine Tree tester.

Does any one have an ingot of factory produced 60/40 solder they might hardness test for me as a comparison?

Given the high percentage of dirt removed from the scrapings and the amount of heat required to separate the solder from it I am wondering if a significant proportion of the tin in the original solder oxidized and bonded with the dirt. Although I fluxed during the process I wouldn't claim it had any great effect due to the huge amount of crud in the pot which made stirring the flux down nearly impossible.

All input gratefully received.

[felix]

Stocker, only antimony/arsenic/bismuth will harden our lead to any extent. ... felix

[stocker]

Felix: I'm aware of that and had considered that those elements might be deficient in the W/W metal although they are usually minimal to begin with. When I mix W/W metal from the same batch of ingots with pure tin rather than the solder all the hardness numbers then seem to fall into place which leads me to conclude that the W/W metal is more or less normal and the solder is not what it sems to be. It doesn't make the alloy unusable , just needs to be used for different or specific purposes. It has me puzzled. Thanks for comment.

[felix]

Stocker, use the 60/40 for tin only. Assume 50/50 and you won't be too far off. ... felix

[montana_charlie]

stocker,
I have a fifty pound slab of 63/37 solder. It will be a couple of days before I can get time to do it, but I will try to figure a way to check it with my Lee tester.
If I don't post something by (say) Monday morning, send me a reminder by PM.
CM

[stocker]

montana charlie: Much appreciated.

[montana_charlie]

stocker,
I (finally) remembered to make that hardness check for you...and figured a way to do it without 'disassembling' my big 'ingot'.

It appears (using a Lee tester) that 63/37 solder has a BHN of 7.4

That's not what I expected, but I've never found a reliable source for the 'official' BHN of straight tin.
CM

[stocker]

montana charlie: Thank you. That is 3 BHN points softer than the solder I salvaged from the rad shop sweepings. Not sure just why the spread should be that much unless there are other components in the salvaged stuff that aren't predictable. Can't think of an easy solution to explain the differences I've encountered so will just continue using it as best suited.

[leftiye]

Am I mistaken, or is pure lead about BHN 7? Montana, I bought one of those slabs too, we may be in trouble. Does anybody know what BHN 60/40 is supposed to be?

[montana_charlie]

Am I mistaken, or is pure lead about BHN 7?
I thought everybody who casts bullets knows that pure lead is BHN 5. It's about as basic as knowing who makes beeswax.
You really need to bookmark this webpage, leftiye http://www.lasc.us/CastBulletNotes.htm .

As for the 'official' hardness of tin, BHN 7 and 9 seem to be common numbers, so an alloy that was 40% lead might expect to be close to 7

That becomes confusing when you turn it around. An alloy of lead with 5% tin is expected to have a BHN of 10.

stocker,
I can't really guarantee accuracy on that number I gave you, but I tried hard to get a reliable reading.
Problem was, because of the size of the ingot, I used a 30 ton hydraulic shop press to push the Lee tester into the alloy. I used a short piece of angle iron as a 'fixture' to press down on the indenter while allowing me to watch for the pin to become level with the top.
I believe the amount of pressure applied was OK, but it lasted longer than the recommended 30 seconds. So the dimple may have had time to enlarge more than a test done in a reloading press. You can only work the pump just so fast, and you have to go slow (at the end) to avoid damage.
CM

[Lee]

MC, the instructions with my Lee tester state a "minimum" of 30 seconds of pressure. I don't think you screwed up the test by applying pressure for longer than 30 seconds. I try to do a consistent 45 seconds when I test. IMO, I think that for a given pressure the test specimen will only deform so much, and that most of the deformation takes place fairly quickly. If you reach an equilibrium point where the pressure applied is less than that required to cause deformation of the sample, then that's it. And I think that occurs when the surface area of the dimple "pushes back" with the same force as the applied pressure. The instructions also state that if the pin protrudes more than 0.015, then throw that test out, as you have over-stressed the test piece. Remember that 0.015 is only 4-5 sheets of paper in thickness, and you see how careful you have to be to judge the "top of the pin flush with the cap" on the tester. That's what I remember from my "Strength of Materials" class, and if I'm wrong, someone correct me!.............Lee;-)

P.S. a quick disclaimer...if the test piece is SO small that the tester keeps "smooshing" out the material as you apply pressure, then you will not get a correct result. I tried to test hardness of a piece of roll solder. That was a disaster as the tester just flattened out the solder all the way down to the anvil. Your test piece has to at least be big enough to take the stresses. (Sounds like yours was!...:-D )

[montana_charlie]

I revisited this thread because I was Googling around the web and came across a webpage that is new to me.

On it, it says the BHN of tin is 51. That is what I meant earlier when I said it seems to be all over the place.

The article also has information on how to estimate the hardness of an alloy...before you mix it up...by using math to get the estimation.

Another little detail I noticed...
It is not important to me, because I don't use alloys with antimony. But this author states that if the antimony content is more than twice the tin content...your bullets will not fill out well...and they'll be brittle.
Make what you like of it...that's what it says.

Seems to me that if you need 850 degrees to get sharp corners, you might be able to get them at 700 if you added more tin.

He also has a great chart for the Lee hardness tester.
http://www.sixshootercommunity.com/articles/cast_bullet_hardness.html

CM