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Apartment complex asks about proper repainting of old galvanized doors

I work at an apartment complex which is about 25 or more years old and the paint was peeling off the doors so we got prices to replace them ,then someone said about sandblasting them , now we have a large amount of rust spots showing up through primer and one coat of paint .should they have been blasted, what should they have been painted with , can you fill me in a little please .

Rodney Glunt
maintenance tech - Chambersburg, Pa, USA
November 18, 2008

If it was my problem I would try to repair the door in situ. Use a good wire brush attached to a drill and/or abrasive wheel to remove rust (beware of dust). Over in the UK you can purchase small bottles from auto stores of a solution that passivates the metal (turns metal black and slows down future rusting)- apply this. After two hours apply a "Zinc RICH Primer" (95% Zinc approx.). After 24 hours apply car body polyester filler if it is required to obtain a level with original door substrate, after 1 hour, sand then paint door with household standard paint, maybe with a 1st coat of primer then a finish top coat.

Terry Hickling
Birmingham, United Kingdom
November 19, 2008