How to recover from painting acrylic paint over oil based paint?

[wharfie0403]

Hi team, I'm hoping I can get some advice. I've painted over the top of oil based paint with acrylic paint without realising. The 2 coats of undercoat (Dulux acrylic undercoat) was all cracking the next morning. Can someone advise the best way (and hopefully easiest) way to recover from this? Do I need to strip it all back and use a primer? Your advice would be much appreciated. Thanks

[MitchellMc]

Welcome to the Bunnings Workshop community @wharfie0403. It's fantastic that you've joined us and many thanks for your question about paint application.

Was it the Dulux Prepcoat Acrylic Sealer Undercoat White that you've used? There are a few reasons why the coating could be cracking. The first is, as you've mentioned, it was either a smooth or glossy oil-based paint or the surface was contaminated, or you didn't apply a thick enough coat.

If it was an oil-based coating or the coating was contaminated, you'll need to sand off the undercoat and then sand back the wall paint to a dull and rough finish. You can then apply Dulux 1L PRECISION Maximum Strength Adhesion Primer White over the wall and, once dried, your topcoat. The Precision primer is ideal for hard to paint surfaces and ensures your topcoat will stick.

If you used a very fine napped roller, say a 4mm pile, then you might not have applied enough undercoat. If this is the case, you can sand back the affected areas and re-apply using a 12mm nap roller instead. Occasionally, if a thick coating isn't applied to a suitable substrate, cracking might be seen.

Please let me know if you have any questions.

Mitchell