Was told I was 'overcleaning' boards with alcohol - turns out they were right

A guy in my local repair group in Chicago called me out for using 99% isopropyl on every board even after I just replaced caps. He said I was stripping the flux residue that actually protects the traces over time. I argued with him for like 10 minutes before I looked it up. Turns out he was right - leaving a thin layer of no-clean flux actually prevents oxidation on older boards. Now I only do a full alcohol scrub if the board has visible gunk or leaked caps. Has anyone else had to unlearn a habit like this from a random critique?

2 comments

2 Comments

the_robin1mo ago

Didn't Rossman say something similar about flux protecting joints?

lee.diana1mo ago

Used to roll my eyes at the whole flux thing, thought it was just people overcomplicating soldering. But after watching a few of Rossman's teardowns where he really breaks down why flux matters, I changed my mind completely. @the_robin you nailed it, he literally shows how a good flux barrier keeps oxidation from messing up your joints before the solder even hits. I tried it on an old laptop board last week with no-name flux vs good stuff and the difference was insane. One side turned out crusty and the other side looked perfect, no bridging at all. Kinda embarrassed I doubted him for so long, but better late than wrong.