Why does everyone keep using the wrong flux for SMD work?

I see it all the time on here - people complaining about cold joints and bridges on tiny boards, then they post a pic and it's clear they're using that dark sticky rosin flux meant for old-school through-hole stuff. At my bench in Austin I switched to a no-clean gel flux from ChipQuick about 8 months ago and my success rate on 0402 resistors went way up. Has anyone else noticed the difference or am I just lucky with that brand?

3 comments

3 Comments

the_lee28d ago

Man I had the exact same mess with that dark rosin stuff on 0402s.

elliot_patel28d ago

I read this thing by a guy who worked at NASA's soldering lab back in the 90s. He said the biggest mistake hobbyists make is treating all flux the same. The dark rosin stuff is fine for big joints but on SMD it leaves this crusty residue that traps heat and makes bridges way worse. I switched to a no-clean gel too but I use Kester's regular stuff not ChipQuick. The difference on 0402s was night and day for me. Less bridges less cleanup.

julia_anderson28d ago

Treating all flux the same" I actually switched TO the dark rosin stuff on SMD and it fixed my bridging issues.