Homebrew PCBs

For touch ups I would suggest, with the right ink, the technical pen would
be far superior to a sharpie because you can just set the pen tip down and
ink will flow. No need to rub it around. I always found sharpies difficult
to get a good / durable layer built up. The tech pen ink used to be much
more resistant to etch as well. I see the bottle I have is Staedtler #485
23SAR-9. The R may be a P. There's a bit of ink dried on the container. A
google search on anything to do with technical pens draws a blank as far as
I can see. Staedtler does still have a selection of "sharpie" type markers
that may be better than an actual Sharpie.

 I believe they also had a technical pen ink that was used somehow in the
ceramics industry. Maybe to autograph mugs or something?

That may be another place to look for a good ink.

 

Sage