I need to tack a zinc plated bolt to a steel plate... should I just grind off the zinc plating where the tacks will be? Also will the heat greatly affect the strength of the bolt? (Should I do 1 tack and let it cool before the next tack??)

The bolt is a 1" x 3" bolt so it will take a lot of heat to get it hot.

I also will be doing the same to a 1.5" bolt on the next project......