Garage Door Repaint

[polygonum]

We have a very ordinary garage with a very ordinary metal garage door.

The paint is in a bad way - and I have been ignoring it for years. But as the door is perfectly functional, I would rather re-paint than replace.

What is best approach? Worth stripping off the old paint? If so, how? Or only where it is doing so already?

Something I have never done and don't want to end up making far more work than needed. At the same time, I want it to look OK and last reasonably.

Given recent weather, I don't think I will be starting for a while, but that leaves plenty of time to mull over any responses.

[newshound]

Is it definitely painted? Quite a lot of metal garage doors are either galvanised or plastic coated steel. It may be painted over galvanised.

The correct approach depends on what you have got. It's not (particularly) easy to sort out failed plastic. If it is painted over galvanised it is relatively easy. If it is painted mild steel, preparation is the key thing. I suppose it could be painted aluminium: check with a magnet and report back!

[polygonum]

I think it is a Henderson mild steel or galvanised. Definitely not plastic, pretty sure not aluminium. The current topcoat is certainly a pretty ordinary paint but you can see some sort of original finish/primer underneath in parts.

[harryagain]

You can get etch primers suitable for aluminium or galv. B&Q had them. After a coat of this, you can use any metal paint. If you don't use an etch primer the paint may peel off.

[Bob Minchin]

>Also make sure you don't go through the galvanising when preparing the surface for the primer.

[polygonum]

>>>

That is one of the things that was concerning me. Saw some handy knotted wire cup brushes in Lidl, thought, that would get the old paint off - as well as any primer or other protection such as zinc... Hence did not get one and am asking now. :-)

[fred]

I'd use paint stripper on it. If you only remove patches of paint with a scraper it may end up looking like a dogs dinner.

[Another John]

I repainted ours 3 or 4 times in the 20 years we had it. It was about 8' wide and 6'2" high. I always just sanded down the rough or loose bits, then undercoated and glossed with standard exterior Dulux, using a small ("radiator") roller, which gave a lovely finish, and also easily gave me the reach required to do such a large surface.

I think the latter couple of times I did it I didn't bother with the undercoat.

It all comes down to "finish required" versus "time you're prepared to spend".

John

[polygonum]

I rather like the orange-peel/stipple effect you can get like that.

[newshound]

>>>>>

You won't take real hot dip galvanizing off with a wire brush. Hot dip is easily recognised by the crystals on the surface. Even the thinner zinc powder coatings are fairly durable. Zinc based paint will come off if you are sufficiently aggressive. The usual rule for painting almost anything is to remove anything loose, but it is normally OK to paint on top of a well-adhered coating.

You can distinguish steel and aluminium with a magnet.