Hey guys, when doing body work, closing up holes, be they old bolt or whatever, what is the rule of thumb, or common sens, on how big you just weld up and how big you make a piece and weld in for? i.e. dime size you just weld, nickel and bigger make a plug?

I saw the trick with the copper behind the hole to weld against, was going to try that one some of the smaller ones.

Thanks.

Red