Cracked outdoor paint - Advice needed

[Ray1000]

I'm re-painting the front door and steel garage door.

Could you tell me the best way to prepare for undercoating and if there is any particular paint to use to lessen the chances of it happening.

I always use oil based paint, I have an electric sander and a blow torch.

Will I get away with just sanding the lightly crazed areas?

Thank you

Ray

 

[Jurassicspark]

Will I get away with just sanding the lightly crazed areas?

Yes.

 

[Ray1000]

Thank you
Ray

 

[JohnD]

Thick paint is more liable to crack. How thick is it, and how old?

 

[Ray1000]

And strangely it’s something I always avoid, I try to get away with the thinnest coat.
I'm presuming it's best to burn the paint off the door frame and just rub down the garage door ?
They were both painted last in 2008, the same time as this bathroom skirting.

 

[JohnD]

The door frame looks like crocodiling. I have seen it on old woodwork that had old linseed oil paint with modern gloss on top. I think it is caused by the paint beneath being softer. Possibly when heated by the sun or undercoat not fully hardened.

Possibly an incompatible undercoat or primer.

I dealt with it by burning off and sanding back to bare wood.

If the garage door is galvanised steel, try not to sand through the galvanising or it will rust.

 

[Ray1000]

Thank you John, I'll watch out for that on the garage door.
I wondered if the hard wood 1962 door frame was not allowing the undercoat to sink in?
Where I've burnt it off it's showing the "pink primer" they used to use

 

[JohnD]

If it's hardwood, then Aluminium Wood Primer (which is grey, not silver) is very durable outdoors, and adheres well to hardwoods. It also seals knots unless they are very resinous.

It needs a lot of stirring as it contains fine metal particles.

 

[Ray1000]

Thank you John, I’ll try that
Ray

 

[Ray1000]

Rubbed the garage door and frame down today, a coat of gloss black on the frame and a coat of oil based undercoat on the worst parts of the door.

I’m wondering if there’s an outdoor fine filler available for painted metal - apart from Cataloy Paste - to level the paint thickness up where it had flaked off … ?

 

[Eccles]

I always used to use oil based which of course always eventually develops cracks then one day decided to go for acrylic on the barge boards a few years ago which I got from Wickes. OK it's not as shiny but it doesn't seem to crack, been on their now for 8 years.

 

[Ray1000]

And I've got some ... I may try it on the front door frame which I've been burning off this morning. Thanks.