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Solder mask touch-up - OK to use clear nail polish?
Posted by: djc6 on 2025-04-11 10:49:43
I am working on an SE/30 with some leaking cap damage. There are some minimal spots where the solder mask is missing from traces. I'd like to put a tiny dab of something to prevent any accidental shorts.

Is it OK to use clear nail polish? I'm afraid to use real solder mask and a UV light - I've seen videos of people giving their logic boards a sun burn.
Posted by: zigzagjoe on 2025-04-11 11:21:03
I am working on an SE/30 with some leaking cap damage. There are some minimal spots where the solder mask is missing from traces. I'd like to put a tiny dab of something to prevent any accidental shorts.

Is it OK to use clear nail polish? I'm afraid to use real solder mask and a UV light - I've seen videos of people giving their logic boards a sun burn.

This is my go-to: https://www.amazon.com/MG-Chemicals-Overcoat-Pen-Green/dp/B0111O7AJM

Good for protecting exposed copper, tacking bodge wires down, and can be soldered through if required.
Posted by: obsolete on 2025-04-11 14:36:20
This is my go-to: https://www.amazon.com/MG-Chemicals-Overcoat-Pen-Green/dp/B0111O7AJM

Good for protecting exposed copper, tacking bodge wires down, and can be soldered through if required.
I've used that before. It's good, but it has some limitations; it's basically just green paint, so flux remover will take it right back off. Make sure you have all your cleaning done before applying it.
Posted by: zigzagjoe on 2025-04-11 14:42:12
I've used that before. It's good, but it has some limitations; it's basically just green paint, so flux remover will take it right back off. Make sure you have all your cleaning done before applying it.
Yep. it won't stand up to flux remover or acetone based solvents (for long). Sort of like colored superglue.
Posted by: adespoton on 2025-04-11 15:01:31
Yep. it won't stand up to flux remover or acetone based solvents (for long). Sort of like colored superglue.
That said, nail polish won't stand up to acetone based solvents either, being the key ingredient in nail polish remover.

Has anyone used superglue for masking? For some reason, I've never thought to do that.
Posted by: djc6 on 2025-04-11 15:19:17
I've used that before. It's good, but it has some limitations; it's basically just green paint, so flux remover will take it right back off. Make sure you have all your cleaning done before applying it.

That good information - makes me like it even more 🙂 I'm fine with leaving this as the final step, and I like knowing any mistakes can be corrected.
Posted by: djc6 on 2025-04-14 07:14:09
Would you bother covering up this exposed piece of ground plane near capacitor C1 ? The capacitor legs don't seem clsoe enough to short it out.

But should I cover it up so it doens't get worse? Any tips on cleaning it up - just a fiberglass pen?

Or the 2nd picture the trace connecting C12 to a via

IMG_6813.jpg



IMG_6816.JPG
Posted by: djc6 on 2025-04-14 10:25:47
Here is an example with important tips on using UV solder mask (I don't plan on doing this) on a LC575 Mystic motherboard.
  1. Use very thin amt of UV solder mask or else it won't cure
  2. <ask off area around the UV solder mask with tin foil
  3. Don't use the UV light too long or you'll burn the board. I think most products claim to cure in seconds?
I wonder if it would be safer to just let it cure in sunlight. Video link below should start at 18:41 timestamp:
Posted by: djc6 on 2025-04-14 10:35:47
Here is a good video on UV solder mask technique:
1