Circuit board solder drippings

[stillhere]

My 'preferred' scrap yard had 10 3-gallon metal buckets 1/2 to 2/3 full of solder drippings. Looked to be clean; no mixed junk The yard guy said it came from a local company that makes circuit boards for aircraft. I hoping it will good stuff; I bought the whole lot, all 600 lbs of it.

[JonB_in_Glencoe]

That's probably all Lead-free solder. I can't imagine there are any electronics companies still using solder with Lead content. The small PCB (printed circuit board) company I use to work for, switched from 63/37 to Lead-free solder in the around 2005, and they were the type to hold out til the very end, when it comes to mandated changes, like I assume that would be.

Once you get some cleaned up, be sure to check out the melt temp.

[OptimusPanda]

Yeah the lead free solder is a tin/silver alloy I think. I've found though it doesn't take to old terminal strips that have been lead soldered in the past. Makes amp repair a real pain sometimes.

[garym1a2]

Aircraft/Military/automotive could still be 63/37 SN/PB. Leadfree is typically 96/4 to 97/3 SN/AG. Tin/Silver. Sometimes leadfree has a dash of copper in it.

[stillhere]

It is rather heavy. It's hard to believe this stuff is lead-free. I just hope this stuff doesn't have lead in it. Maybe I'll melt a pure batch and see what the boolits look like.

[garym1a2]

Leadfree melts about 221Celcus.
63/37 melts about 180Celcus. Both make great bullets.

It is rather heavy. It's hard to believe this stuff is lead-free. I just hope this stuff doesn't have lead in it. Maybe I'll melt a pure batch and see what the boolits look like.

[knifemaker]

If that is that high in tin content, you might be better off mixing a ratio of 16 parts pure lead to one part of your solder drippings and see how those boolits cast and shoot. melt a ingot and have it tested for tin content. If almost pure tin, you can sell it at a good price or exchange for a larger amount of lead for your boolit alloy.

[stillhere]

It will be interesting to see how it behaves on its own in the pot and mold. If it's promising, I'll just keep it, mix it, and shoot it up.
None of the scrapyards around here use XRF scanners so I may never know exactly what it is. No big deal.
I love finding mystery metals. Mystery metals that cast well, that is.

[Cowboy_Dan]

As far as I know, most rolls of solder sold today are 95+% tin and the balance silver, copper, or antimony. Again as far as I know, it is usually only one of the preceding balance elements which varies based on application. I think silver is preferred for electronics.

[dilly]

I think this is the perfect opportunity to send your lead off to an analyzer. You may have thousands of dollars worth of tin there.

[stillhere]

I melted 6 or 7 lbs in my casting pot. Melt point appears about between 300 and 340. For fun, I cast a few 45 Colt bullets. Normally, they drop at about 255-260. The solder bullets weighed right at 195, so that's about 25% less than with the normal alloy. These are the shiniest, smoothest, most beautiful bullets I've ever seen. But they weren't easy to cast because the sprue goes from watery to hard instantly. So I had to remelt the sprues with a propane torch, then cut them, and then open the mold.
168069

Using the Cabine Tree tester, hardness comes out in the 24-28 BH range. I think I have a winner, which is great since I bought the whole 600 lb mess.

[wadcutter]

It's 63/37 Sb/Pb based on the weight. Also 63/37 is a true eutectic, and solidifies in a flash at 183C, whereas lead free solder like SAC305 has a mushy phase between 217-221C.

Almost all military soldering is still tin-lead.

[bumpo628]

From the melting point sticky:
621° = lead
563° = solder (10% tin & 90% lead)
529° = solder (20% tin & 80% lead)
504° = solder (30% tin & 70% lead)
464° = solder (40% tin & 60% lead)
428° = solder (50% tin & 50% lead)
374° = solder (60% tin & 40% lead)
362° = solder (63% tin & 37% lead) (eutectic)
365° = solder (70% tin & 30% lead)
392° = solder (80% tin & 20% lead)
421° = solder (90% tin & 10% lead)
450° = tin

The lowest melting point on the list above is the 63/37, so that is probably what you've got there.
Search for member BNE, he will test a sample with the xrf gun for the cost of 1 lb of any lead alloy.

Looks like you're sitting on at least $4000 worth of alloy there. Nice score!

[stillhere]

Glad I bought it. The guys at the scrap yard know me well. I'm always trying to beat the guy from the battery company that comes around.
There was quite a bit of ash when I melted it. That must be old flux or something. I fluxed with sawdust and that reduced a lot of the oxides back into the melt. Between this and the babbitt, the pewter, and all the solder bars, I'm pretty sure I'm set for life on the tin supply, which is something I thought would never happen when I started collecting metals a year ago.
Not sure I'll ever feel that way about lead, though. Is 2500lbs enough? It doesn't seem like enough. I mean, I can shoot 10-12 lbs in a single afternoon, so I'm gonna say no, it's not enough.

[merlin101]

Is 2500lbs enough? It doesn't seem like enough. I mean, I can shoot 10-12 lbs in a single afternoon, so I'm gonna say no, it's not enough.

Don't forget you can reuse range scrap, build your own boolit trap and you'll definitely have a life time supply!

[Alan in Vermont]

When Digital Equipment had a plant here they were using 96.5% PB/3.5% SN in their wave solder process. A buddy has several hundred lbs. of the alloy slugs they added to the pot in the original boxes with alloy marked on the labels. He gave me a copper plate that caught drippings and it was analyzed and is very close to the 96.5/3.5 as well.

[garym1a2]

Normal leadfree for wave solder is mostly 96.5sn/3.5ag(220C)


When Digital Equipment had a plant here they were using 96.5% PB/3.5% SN in their wave solder process. A buddy has several hundred lbs. of the alloy slugs they added to the pot in the original boxes with alloy marked on the labels. He gave me a copper plate that caught drippings and it was analyzed and is very close to the 96.5/3.5 as well.

[6622729]

Fantastic! Great purchase! I also agree this is likely 63/37 tin/lead based on the weight.