Overheard a HVAC tech say 'flux is just acid with better PR' and it made me rethink my soldering

I was at the counter at my local electronics supply in Akron last Saturday, grabbing some new tips for my Weller station. This older HVAC guy was talking to the owner about fixing a control board and he just dropped that line. Never thought of it that way. I've been using the same rosin core solder for years, never really bothered with extra flux unless something looked crusty. Now I'm wondering if I've been making my joints weaker by not cleaning off residue properly. Anyone else ever had a joint fail months later from flux leftover?

3 comments

3 Comments

seanjackson4d ago

Flux is just acid with better PR" is catchy, but I've never had a joint fail from rosin residue left on.

dianahayes4d ago

Miles' buddy's crusty brown flux story is way worse than any rosin issue. That stuff looks like a science experiment gone wrong on a circuit board. Never had a joint fail from rosin either, but I'd still clean it off just for looks. Who wants coffee crust on their work?

miles_roberts4d ago

My buddy Dave built a guitar pedal once and used some no-clean flux that turned this weird crusty brown after a few months. Didn't kill the joint but it looked like someone spilled coffee on the board. He still uses it because he's lazy and says it's fine, but I always wonder.