[quote name='lettsguitars' timestamp='1341944745' post='1726827']
The powder coating wont stop a current. Just attach one end to the mains and hold on to the other end for proof. The screw will eat straight throu the 'black' and make more than adequate contact with your groundwire. The bridge needs to be absolutely flat and solidly seated on the body and any thing, even paper thickness will affect the tonal transfer which is why you have to make a channel.
[/quote]
right you are. I am a bit of a bloody fool, I mean it's an ionised coating- of course it isn't going to stop a current! Duh It's not even the bridge ground that was the problem, it was my crappy soldering onto the ground on one of the volume pots, which should have been pretty f***ing obvious to me since it did make a much less loud hum when I touched the bridge! I don't know, I am a f***ing idiot sometimes I don't think I am having any problems with tonal transfer- the thing sustains for days.