Paint adhesion problem. How to resolve? Any paint experts here?

[Adam4868]

Leyland Trade, (or most trade paints) seem to be the way to go. Not the watered down shi1te they sell for DIY use.

That's what I've allways used....never really had a problem.

 

[kynikos]

It should certainly perform better than it has done but I'm not sure "I did perfect preparation before painting" is necessarily true. Recoat time on your undercoat was likely a couple of hours. With a different colour going on top it may have been sensible to leave it until the next day, at which point it will have still been a little bit tacky thus giving good adhesion. By leaving it to dry for 6-8 weeks the undercoat may have hardened off to the extent where it's no longer in an optimum state for a further coat to adhere properly - with an argument being that, after such an interval, you'd have been better to have lightly sanded the walls to provide a key.

I say this from recent experience where the second top-coat I was applying just didn't adhere as I'd inadvertently left it too long. Different paint, different manufacturer, but it was only when I read the instructions on the back of the can that I discovered:

• Test a small area first for adhesion...
• Adhesion: If adhesion is inadequate on previously coated surfaces, lightly sand before application.
• Minimum of two coats required. Subsequent coats must be applied no longer than 8 hours apart.

Cue a couple or three hours sanding and cleaning down and a self-kicking.