
grinding and brushing will NOT completely remove the Zinc plating. you can weld it, but the gas emitted will seriously compromise your welds.
there's an easy way to deal with it. go to any pool supply or hardware store, get a gallon of Muriatic Acid for $3.
brush it on and rainse off with tap water, you are good to go. it takes the acid 5 seconds to eat away the zinc plating.


Also, when you do weld it...hold your breath and/or use a fan....