The molten zinc is at about 825-850 degrees. This is not a problem for frames or any other heavy steel, but can cause damage to sheet metal parts. I would
never galvanized (at least not hot-dip galvanize) any formed sheet metal body parts.
If you realy want to galvanized sheet metal, electrogalvanizing, where the zinc is deposited by electroplating, would be worth looking into - although I think the temperatures used are also quite high.
Hot-dip also leaves a fairly rough surface - not something suited for any more than underbody work.
As far as powder coating goes, the oven temperature is around 375-425 degrees and doesn't cause any damage to sheet metal (although I would definately have them heat it at the lowest possible setting).
Here is an article about zinc coated steels in automobile manufacturering (starting on page 196):
http://books.google.com/books?id=s0i...I5-EeU#PPP1,M1
