recently when i replaced my jack socket for my guitar the jack sockets length was a few mm short, so i had to drill down into the wood of my guitar for it to stick out far enough for the nut to go on. When i did this i took away some conductive black paint to make space for the jack socket. now when i plug it in my amp has awful mains hum coming from it. do i need to get some more of this black conductive paint, and if so where can i get it from, OR could i make do with some electrically conductive silver paint from Maplin to connect to the black paint.
Try either type of paint, but i'm not entirely sure if that's the problem. Did you wire the jack correctly? the inner circular part is connected to the ground lug.

Shield paint only stops RF, not EMI. EMI is much stronger than RF, so a thin little coat of paint isn't going to stop it.
Check your connections to the jack socket. You may have the tip and shield reversed.

Conductive paint is meant to add a little shielding, but it isn't meant to replace a ground wire. If you only have a wire to the socket and are depending on the paint for ground, this will not work well at all.
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