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What solder does everyone recommend, for general Arduino soldering?


If you're reselling, you are probably required nowadays (depending on country) to use unleaded. But aerospace and medicine have exceptions to avoid this dreadful stuff, and for good reason. Unleaded solder is useless, awkward to use and unreliable in service.

I disagree. I use Kester Sn96.5/Ag03/Cu0.5 in a half mm diameter on a daily basis and it's always been just fine. The joints naturally have a frosted look from the quick crystallization but other than looks it flows fine and makes perfect joints. I use an additional flux that I've made from an old patent. The key I think is the added 3% glycerin that prevents the flux from burning. You can get pine rosin by the pound on eBay and make your own too, though a pound would last several lifetimes.

As for tin pest/grey tin, I think that requires some testing. I think tonight I'll stick some copper clad in the freezer with some of this part tinned silver/copper mixture and one in a cabinet for control and see what happens.

im still experimenting with different solder.. as apparrently u do :-)

i used 60/40 tin/lead - 0.5mm but disliked it very much.

allthough i thought it were my bad solder skills the 99/1 tin/copper - 0.7mm seems to prove me otherwise. this solder is a relief to work with.. i can advice it for general trough-hole. but i dont know the mechanical differences with other solders

Really? ...you really prefer rohs over 63/37? That is honestly the first I have heard an argument for rohs in a non environmental context. I have used rohs solder many times (I keep a small spool on hand for 'outside jobs'... jobs where someone I don't know will possess the hardware). It is a pita to deal with compared to 63/37 no matter what size/shape/materials the joint involves.

63/37 rosin core 23awg (0.02")... I prefer Kester but MG Chem isn't bad.

Thanks everyone

60/40 Tin Lead Rosin Core 1mm solder for through-hole parts.

Very thin rosin core like Kester around 0.5 mm in diameter. Get a secondary flux source too.

I agree with Phistterbut_Inc.
I will add to that by saying that it's not a good idea to mix lead-free solder with regular.


But what should also be mentioned is that lead-free solder requires higher temperatures (which one would like to avoid in part)!

I like lead... As hobbyists we probably all die before from an electric shock, or because our own drone chases us... ;)


Agreed, Rohs is a great idea for commercial manufacturing as it saves us from putting 1000's of tons of lead in land fills. But for hobbyists the workability of 63/37 is nice, and if I added how much lead solder I've discarded over my lifetime it is maybe a gram or 2? ...and folks who solder as much as I do at home are rare. Collectively we as hobbyists generate very little lead contamination... very manageable imho. Now otoh if all my computers and gadgets were non rohs... I'd have tossed close to a pound of pb in the bin by now.

Did you guys know that rohs solder created all kinds of problems with tin whiskers in space based hardware? Our garage circuits built with 63/37 would not have such issues in space, lol!

Agreed! I am surprised I am still alive. Sometime in the late 50's, I decided to see what happened if I applyed 600 VAC to a metal electolytic capacitor. I hooked it up with a 600V transformer, stood back, and plugged it in. nothing much hppened right away, so I grabbed it to see if it was getting warm. It started to heat up, so I pulled off one lead and the wire swung into contact with the palm of my hand. What I learned from that, after waking up on the floor, was that the metal can was actually connected with one of the contacts. Of course I also learned that that sort of voltage and current does a fair bit of 'cooking' of the skin (but only on the hand the wire contacted), and that from then on, I was forever going to remember to be more careful.

Good thing you weren't touching anything else. The current would have gone in/out the other point of contact. More than just your your hand would have been poked.

Well, it did go in/out, from one hand to the other. The only reason I am still alive (I assume) was that as I fell, the circuit was broken. The transformer was on the floor, and my left hand was still holding the metal can. The right hand had nothing in it... just a few small burns.

Yep, rosin multicore 60/40 tin/lead, 0.7mm for me.
Had a similar experience to you, lar3ry. Back at school in the 'seventies myself and a couple of friends found an ancient valve (tube) driven resistance tester under the the hall stage. (We could go in there at lunchtimes as we did the stage lighting.)
I had first go at testing my resistance; plugged it in, turned it on, waited for the needles to stabilize, grabbed the terminals and WALLOP! Don't know what voltage it shot through me but it gave me a very healthy respect for electricity for the rest of my life.

1LB Spool Kester 63/37 rosin core solder (Ideally not expired) and choose the appropriate diameter for your use case, something less than or equal to 1mm for arduino type stuff.