Testing lead free alloys

[Don1357]

I have some unmarked soldering wire. Is three an easy way to test and see if it is the lead free variety?

[richhodg66]

Send a tiny sample to BNE. He did this for me in exchange for a pound of two of lead and I am very happy with the way he does things.

[Don1357]

I have a bunch of pieces. Mailing a sample of each would not be sensible.

More importantly every once in a while the local recycler has a bucket with both marked spools and unmarked ones. I buy the stuff i can identify at $4/pound but im leaving the rest behind. It would be nice if i could test it somehow.

[Dusty Bannister]

If you have solder and it is not identified, then make one batch and have the batch tested. If you have a hot plate, and a solid aluminum plate to lay on it, you might put on several small samples and turn on the heat. The ones that melt at the same time are likely to be the same percentage of tin. More tin melts at a lower temp.

[richhodg66]

I have a bunch of pieces. Mailing a sample of each would not be sensible.

More importantly every once in a while the local recycler has a bucket with both marked spools and unmarked ones. I buy the stuff i can identify at $4/pound but im leaving the rest behind. It would be nice if i could test it somehow.

Suit yourself, but I sent him samples of three different things and a couple pounds of casting alloy per sample as payment for the cost of a small flat rate box. What I got in return was that the 30 pounds or so of lead free air rifle pellets I had accumulated were pure tin. Dirt cheap at the price for me to know what I had.

[kevin c]

Richhodg66 and Dusty's recommendation to batch is what I'd suggest too. The way I look at it, a bunch of spools of different solder with different tin content means a new calculation on how much to add to each new pot of alloy. It gets worse if I'm making a large amount of alloy (and I do) needing more tin than is available on all the rolls of solder of the same type.

Batching it all means it's all one content, simplifying blending the alloy. It also means that you can buy the unmarked spools from the recycler, put it all into the batch, and get one analysis at the cost of one pound of lead plus shipping to BNE that'll tell you exactly how much tin you have in terms of both the total and the percentage.

ETA: I might not batch if the total quantity is small, or if the solder is for resale (some folks are more comfortable buying metal scrap for alloying when it's in its original form so they're sure of what they're getting).

[JonB_in_Glencoe]

What are you gonna use it for?

If you are just going to use it for blending boolit alloys, you don't need to know the exact percentages. I would just melt all your solder into one large batch, then use the Melt temp-range to guesstimate your alloy, Kester has a good chart.

https://www.kester.com/Portals/0/Doc...re%20Chart.pdf

I was given some mystery ingots many years ago, I suspected a PB-SN solder...someone wrote on them with a magic marker, "tin". but I was skeptical. So I melted all the ingots together and observed the melt temp and the freeze temp and the "slushy" stage inbetween. Then using that Kester chart, I deduced the alloy was PB50-SN50 solder.

FYI, eutectic solder (SN63PB37) doesn't have a slushy stage.

[kevin c]

JonB, what a practical application of science! And from the chart, it looks like it works for trinary solders too.

What can you use for this? I think my convection oven with a digital temp probe would work if I started low and edged the temp up bit by bit, at least for the lower temp ranges (I don't think it'll hit 600 degrees). Or is there another way?

[JonB_in_Glencoe]

I had about 8 lbs of ingots, The ingots were large, and I wanted to make them smaller anyway, plus I wasn't sure if each ingot was the same content either. So I put them in my Lee pot with PID.

I think you could probably get close enough with a analog thermometer, especially of you have a way to calibrate it...Boiling water works kinda OK, but it'd be better to have something to calibrate it near 400º

FYI, after I got my PID setup, I compared it to my Lyman lead alloy thermometer, and it was off about 20º in the 700 range, I am assuming the Lyman was off and NOT the PID, LOL? I'm not sure what error I would have at 400, but it would not be accurate enough, IMHO, for the test I described.

EDIT:
Actually, if you have a PB-SN solder with a known SN content near 50% not over 60 or under 40, according to that chart, it melts at 361º You can calibrate to that.

[Don1357]

Suit yourself, but I sent him samples of three different things and a couple pounds of casting alloy per sample as payment for the cost of a small flat rate box. What I got in return was that the 30 pounds or so of lead free air rifle pellets I had accumulated were pure tin. Dirt cheap at the price for me to know what I had.

What I have is more like 20+ small chunks and the desire to figure out a way to pick and choose from the recycler's bucket.

But the idea of grabbing it and smelting it into a single batch I can have tested is brilliant.

[lightman]

If you are trying to acuminate a stock of solder I would just buy whatever he has and melt it together. Sometimes the % is still legible on the spool and sometimes not. I don't know of an easy way to tell by looking while at the scrap yard unless they can do XFR testing.


I save up odd rolls of solder until I have 20# os so and melt it together into one batch. Then I send a sample off to be analyzed. The last batch ended up being 51% tin and 49% lead. I leave any bar solder in its original form as long as there is a marking on it.