That depends on whether the places where one sees rust are friction points
when opening or closing said door. Without an understanding of the
mechanism, it is almost impossible to know. Personally, I'd be looking at
the mechanism as well for hidden problems that might be more than of
cosmetic annoyance. The plastic coated untreated steel is notorious for
getting cracks, the water gets in and the coating starts to debond and fall
off. One often needs to get back to a good bond and treat it with some kind
of zinc based paint then paint the whole thing.
However ones rust starts as on cars it can be only when the paint blisters
somewhere and the rust comes through, that you know about it.
Brian

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This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"newshound" wrote in message
o.uk...
On 15/05/2018 20:34, Jim K wrote:
newshound Wrote in message:
On 15/05/2018 19:37, PeteFJ wrote:
Two years ago we had a new garage door fitted. The old one was very
rusty and at 20 years old, coming to the end of its life. We live in
Cornwall and the sea is only 6 miles away which is also the direction
of
the prevailing wind.

The new door is starting to show rust spots over the its surface and in
the top and bottom corners.

Whats the best way of treating the rust in order to increase its
lifespan?

petefj

Make of door? Material? Plastic coated steel, or aluminium.


Rust suggests steel...


Yes but the OP is sufficiently imprecise to suggest that they might call
corrosion on aluminium "rust". To me, "Rust spots" could be aluminium
rather than steel corrosion. The corrosion on either painted or plastic
coated steel is not so likely to be "spots", more likely flaking of the
coating with rust around the periphery.

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