Found out most people are using the wrong flux for modern boards

I was reading through some old factory service bulletins from 2018 for a Denon receiver repair and stumbled on a stat that said over 60% of board failures with poor solder joints traced back to using rosin flux on lead-free solder. Turns out the temperature ranges don't match up right. Has anyone else had joints fail after a few months and checked what flux they were using?

2 comments

2 Comments

the_elliot25d ago

Respectfully, I gotta push back a little. I've been using rosin flux with lead-free for years on vintage gear and newer stuff and never had failures unless I was running temps way too low. If your joints are failing after a few months, it's probably a technique issue or bad solder more than the flux type.

blake_black4725d ago

Elliot's been doing this long enough to know what works for them, but I've seen the exact opposite with some of that budget lead-free stuff that claims to be "rosin core". Had a buddy pick up a spool from a surplus sale, stuff looked fine, but every joint he did with it turned into a brittle mess inside of eight months. Couple that with a too-hot iron trying to get it to flow and you're just asking for tombstoning or micro cracks. The real hidden variable nobody talks about is how long you leave the iron on the pad - even good rosin flux will cook off if you're slow.