[mystified5016]

I say this as someone who has been soldering their entire life, but lead-free is fine. The differences between leaded and lead free are minimal these days.

The best way I can describe lead-free solder is like using some old and really crappy leaded solder. It can get kinda gummy and ugly, but usually only when you touch a joint for the tenth time.

The way to make lead free solder flow and work like leaded is simple: flux. Flux pens are alright, but your world will be forever changed by gel flux in a syringe. Clean up with rubbing alcohol and a toothbrush or paper towel.

Modern solder alloys are pretty good. Just don't buy the cheapest thing you can find. Always, always get your solder from a good manufacturer like MG chemicals. Also buy fluxed (not no-clean) solder wick from those guys.

I used to be in the "just use lead" camp, but there's really no benefit. I've been exposed to far more than enough lead in my career. Lead-free is totally fine.

Some people fret about solder whiskers, but I'm unconvinced that this is a real problem worth discussing. It seems to be myth more than a practical problem that anyone but NASA should care about.

Just use good lead-free. It's only trivially worse than leaded. It's fine.