weldable primer?

where can i get some weldable primer so i can sheetmetal my bed... you know... spray the underside then do the welding so nothing gets rusted... can i get it locally? or do i even need to get it?i would like to get it but yea let me know what you think from experience and whotnot please.. thanks

-pascal

we have it at auto zone around here check anywhere where they sell welding supplys or auto paint

any autobody supply store