Laser removal of etch resist (spray paint, laser, then etch)

[mark2]

I've always found the heat transfer of etch resist to be finicky. I eventually found the right magazine to use for toner transfer, and the right toner, and the right iron settings... but even then I'd still have occasional failures.

Well, I have a new hammer (ermm, I mean laser) and so of course everything is starting to look like a nail. A week or two ago I coated some copper clad with cheap black spray paint, and today I tried burning it away with a 50W CO2 laser.

Super short takeaway: This method is great. Much easier and has better results.

After a bit of experimentation with power and speed, I eventually found a setting that melted the paint really well. Then you can just wipe it away with a bit of alcohol. While experimenting I was tilting the PCB slightly to avoid flash back into the lens; I'm not sure if it could damage it, but I figured better safe than sorry.



It etched really well, even with tiny traces for a 1mm pitch SMD connector, just to push the limits.







Unfortunately I burned those tiny traces off. Next time I'll reduce the heat, make them a hair wider, and maybe even put a little nail polish "solder mask" over them.