I often use terminals on my custom perfboards, but i want to paint the terminals to show the polarity (red and black).
I have tried with black pen but the paint dissapers after a while. I have also tried with acrylic paint with no luck.
I thinking of trying nail laquer/polish. It dryes quick and kan buyes in many different colors.
Some other ideas maybe?
I find paint markers to be super useful tools for quick and convenient marking of electrical connectors.
I'm using the super cheap ones you can get on eBay, like these:
There are CD/DVD markers. They give a thin line.
I only have one blue, but I use it very often.
Whats is the difference between the paint in the pens over and habby Acrylic Paint?
For one thing, convenience. I just want to quickly mark the connectors. I can't imagine an acrylic paint option would provide so much convenience.
As for technical differences, I don't know. I've been happy with the markers, so found no need to go looking at other alternatives. You can compare the two if you like. I can tell you that the paint in the markers is solvent-based. They are pretty stinky. I haven't had any problem with them drying out, despite them being years old.
I understand. I will try to buy this pen to day in a local store here in Norway and test 
https://www.staples.no/p/paintmarker-uni-posca-pc-3m-lys-orange/777817?tracking=searchterm:paintmarker
I'm very interested in your findings as well as any approaches taken by others.
In a previous discussion on this subject, someone mentioned that they use "White-out" correction fluid. I happened to have a bottle on hand so I did a comparison and found that the paint marker's paint was a little bit more durable than the white-out.
I also think Nail polish can work. I will try do bye one and test.
But i will try several things.
Acrylic Paint i can use to other thing also. For example can i paint project boxes etc.
I use dollar-store nail polish for a very long time. It is rugged, dries hard and quickly with a hair dryer (or hot air from soldering station.) I use a tooth-pick to apply.
Yes, i think nail polish is a good thing. I will try that too
And curiously, nail polish actually comes in the right colours (red, blue, black, probably green)!
As one of the forum participants said recently:
Take your wife out for supper.
Take a bottle of finger nail polish from your wife's dresser.
I`m not that brave 
I apply White Out over any dark surface and then when it is dry use indelible Sharpies in the colors that I want.
I use Testors red model paint (if you can still find it). My local Ace Hardware store still carries a limited number of colors.
I like it better than the markers and nail polish. Using a fine brush I can easily put small red dots and color the base of a dupont.
That's funny. I do the exact same thing.
As far as I am concerned, that is what White Out was made for. I have never used it on paper.
Print terminal strip labels on paper, cut to size with scissors.
Place cut out on PCB.
Cover with a thin later of UV glue/resin, expose with UV light.
My radical solution to this is to use red and black coloured terminals
Many good ideas here
Regards to the colored terminals i allready have these and all are green or blue. I want to mark each terminal with black and red for negative and positive. For the 3-pin terminals i also want to color yellow or blue for signal lines etc.
I baught this set today. I will try it soon:
https://www.clasohlson.com/no/Sang-akrylmaling/p/34-9247
