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Semi-OT: Favorite lead-free solder for cables and PCBs (but not SMD)?

Jim Feeley

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I spent enough years using lead solder in my youth. And now, even with a small fume extractor, I just don't want to use lead solder anymore. Alas, the lead-free ones I've tried are a bit trickier to use. Perhaps I need to improve and/or tweak my technique. Or perhaps I'd prefer a different lead-free solder.


I'm up for trying flux-core or solid if that'll help... I'm most familiar with Kester, but have no brand loyalty on this. I'm mainly making cables, soldering basic components to PCBs, and doing some fun point-to-point stuff. (So ya, cables for work. Guitar pedals and amps for fun (and I may try a couple synth modules, too)


Kester 275 No-Clean Flux with K100LD alloy is looking like a leading (ha!) candidate:



Have any of you used that? And more broadly, what lead-free solder have you found that you like?

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i have been using this stuff


which has been fine for me. mostly wiring mics and occasionally some PCBs, but nothing delicate with the PCB.
also doesnt spit flux over your hand as you are soldering, which the previous solder i had bought would do.

i would also suggest getting a new tip for your soldering iron as well so you dont mix leaded and unleaded solder on it. 


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Hey Jim,


Maybe reach out to Kester for a recommendation for hand soldering? I know they have a large amount of variants and it’s hard to know as a non-engineer what’s best or what you definitely don’t want to use without an industrial fume system. 

I hear you about lead solder. I still use it, and might just use it the rest of my life since I have a couple spools of it and don’t solder frequently but I go between indifference to moderate concern regularly. I just have a charcoal filter fan to attempt to suck the fumes away. I’ve read confusing advice on solder… that solder fumes are not that dangerous, don’t contain aerosolized lead and the risk is mostly irritation from the flux fumes kind of like a wood fire would irritate as well. But then I’ve read other material that seems to indicate all sorts of horrible stuff in the fumes. 

When they say the fumes are ok maybe that’s assuming you’re wearing an N95 and have an industrial fume sucker on your bench (no affordable version exists that I’ve found). They’re probably not saying it’s fine for Joe Blow sound guy to be soldering in his basement with a computer fan blowing the smoke around. (Basically my setup)

Sorry to hijack your thread with my rant…


Side question for the populace here… have any of you who have been soldering a long time with lead ever go and get a blood test?

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very interested to get feedback once you try this K100LD alloy. It is the first time that I hear about it. Thank you for the lead.

As Derek, I have bought a stock of leaded solder spool after I tried the first unleaded one (tin with silver, Ag) that has lead to disaster...

Quite a while ago now I realize, so I have not been keeping up about the new developments.

I understand after some research that it is a proprietary alloy by Kester.

Not common here in France but I am keen to try it if it sounds manageable.


(PS: nothing OT here I think, so many of us are soldering stuff!) 

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Thanks for the replies. One reason I'm asking: Kester no longer offers the low-cost/short-length pocket paks. For wire, just 1lb/450g (and up) spools; those cost about $50USD each. Same with MG and some other brands. NTE sells a few types of pocket paks with Kester solder, but only one type (and diameter) of lead free. I don't want to buy a few 1lb spools only to find out I don't like a certain type or brand. (And most of my experience is with Kester, so that's my first choice brand).


Anyway, Kester has some good informational documents on hand soldering (as well as wave and SMT, but that's not for me). Here's the hand soldering collection: https://www.kester.com/knowledge-base/knowledge-base#4508-hand-soldering


Two I found helpful:


Lead-Free Hand Soldering – Ending the Nightmares

Hand soldering with lead-free solders can be challenging but not if the points in this article are understood.


Case Study on the Validation of SAC305 and SnCu-based Solders in SMT Wave and Hand Soldering

This paper describes the work done at a contract assembler who implemented a successful process to build over 500,000 assemblies using both Kester K100LD and SAC305 solders.


I had to supply name and email address to get the link to the PDFs, but the docs are pretty good. 


If anyone else wants to chime in, great. And I'll let you all know what I find out.

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I used to worry about this a lot. Then I did this, and those fumes are sucked right out of the house.  A pal gave me a 6" duct fan and it works!  I never want to have to deal with lead-free solder! (Black bag is for cat-proofing the heat shrink!  Bunsen the cat loves to chew that stuff.)





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