what is this coating on metal ?
 

I noticed on some of the thinner sheet metal scraps I bought have a coating on them,what is it and should I remove it before paint.I,m wearing the proper mask for welding with zinc weld thru primer but still would like to know what I,m working with.You can see how it changes color after welding.Is the piece on the right

Re: what is this coating on metal ?
 

the white on the bottom is masking tape

Re: what is this coating on metal ?
 

The piece on the right looks galvanized.

Re: what is this coating on metal ?
 

if the coating is black it's just mill scale; sand or sand blast it off
if it's grey or zinc colored that would be galvanized; don't use it
hard to get paint to stick to galv and there's no safe way to weld it

if you've already welded on galv... does your tongue feel weird?
that's your body being poisoned :(