I need to be RoHS compliant so over the past couple of years I've tried a number of lead-free solders. The best of them had been IA-423, a tin/copper/silver alloy patented by Ames Laboratory and licensed to Johnson Manufacturing. I found it to be closer to good ol' 63/37 than anything else I'd tried.
More recently I tried SN100, an alloy patented by Nihon Superior of Japan. It not only contains no lead, it also contains no silver. It's mostly tin (hence SN100) with a tiny bit of copper and trace amounts of nickel and germanium.
I've been using SN100C made by AIM Solder with their Glow core no-clean rosin flux. It's the best solder I've ever used, leaded or otherwise.
I've seen virtually no mention of SN100 on any of the boards that I frequent and thought I'd give it some mention here. I've been getting it from
ElectroWise who sells it for $17.59 to $27.32 per pound depending on diameter (I prefer the 0.02" diamater for regular soldering and 0.015 for doing surface mount stuff).
Definitely worth a try.
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