I should of taken a picture.

I have a relay board that is missing about 1 inch of the black coating on the bottom.
the PO looks to have put a long screw into the regulator, and it grounded against a circuit by protruding too deeply

the circuit looks good.
the black goo became loose due to the long screw.

what product should be used to patch the bottom that would electrically seal it?

tia
brant

Liquid Tape

Dis:

https://www.amazon.com/Gardner-Bender-07315...0NsaWNrPXRydWU=

Thank you a ton!

If you just want to patch it, the liquid tape is a good choice. If you want to completely replace the old tar potting compound, an epoxy potting compound is probably the best choice. This is what I used and it worked great: https://www.amazon.com/MG-Chemicals-Flexibl...C259&sr=1-4

if the patch doesn't work this is good info

there are no cracks on the bottom
only the one inch round piece missing from the idiot PO
I'm hoping the patch is all it takes.
brant

I'd go with the liquid tape then. Much cheaper and once you have a bottle of the stuff on hand, you'll be amazed how often you use it.

I've used Plasti Dip with reasonable results. You just have to be careful to plug the larger holes so the plastic doesn't leak all over the pretty side of the board. I used a little spackling compound. Once the Pasti Dip dried, I could wash out the spackling.

I looked at epoxy potting compound, but it was pretty pricey.

Gary