I've been making PCBs myself for 5 years already.
- I use UV curing
- develop in NaON (SodiumHydroxide)
- etch in Na2S2O8 (Sodium Persulfate)
- clean finished PCB with acetone
Recently, I've noticed variety of weird glitches with newly made PCBs - hundred kilo-ohm resistance across separate tracks, power leaks, self-resetting MCUs and self-flashing LEDs or self-turning FETs.
When inspecting PCBs under volates (up to 12V) i've noticed weird spots growing in front of my eyes. Absolutely clean PCB gets dirty in approx. 60 seconds.
Further inspection led to a single conclusion - DENDRITES (or ionic contamination).
I've thrown away all my chemicals and ordered a new set of blank PCB material. I've event replaced standard water with the distilled-one as well as bought new welding Flux (Weller).
I do still get the same effect.
What else should I try?
ps: PCB in the photos below was crystal clean 60 seconds before powering it up with a 12V rail.