Painting a Galvanised Garage Door

midships

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What's the best primer and/or undercoat for a galvanised garage door?


I have up-and-over galvanised steel garage doors. The paint was flaking in places. I've rubbed the doors down and there are now several small areas of bare metal. Mostly the old paint is sound. I've treated some small spots of surface rust with Kurust rust converter. Next I plan to wash the doors with sugar soap then rinse and let dry.

The question is what is the best primer/undercoat? Do I prime just the bare metal bits with something, then undercoat the whole door with something else? Or can I use a primer to cover the bare bits and the old paint?

I've looked at Zinsser Bulls Eye 123. Would that be a good primer and undercoat for the whole door?

Or Zinsser B-I-N as primer/undercoat? I've also seen red oxide paint recommended - but would that only be to touch up the bare metal? Or maybe B&Q metal primer/undercoat would do the job just as well as the branded stuff? (I've also seen etch primers suggested but that's just further befuddled me.)

I want the paint job to last so I'd like to buy whatever is best. Any advice from an experienced painter would be most welcome.

benson1980

I just used exterior gloss, no primer; this one in fact:

http://www.wickes.co.uk/Wickes-Exterior-Gloss-Paint-Muted-Olive-750ml/p/214156

I didn't use any undercoat and the finish is still perfect a year later.

midships

Interesting, but not sure that's the best thing - to put topcoat straight on to bare and even rusty galvanised steel - is it?

I emailed Zinsser and they replied saying their Bulls Eye 123 would be good as primer and undercoat - but they would wouldn't they.

Anyway, in the absence of any other advice I've gone with the Zinsser Bulls Eye 123 as primer/undercoat and Sandtex 10 Year Exterior Gloss. Fingers crossed.
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ashleyjohn

Go for epoxy primer, it will stay for a very long time