Waterborne acrylic enamel was painted over oil based enamel.

Questions & AnswersCategory: Latex Paint Over Oil Based PaintWaterborne acrylic enamel was painted over oil based enamel.
Sonia Staff asked 4 years ago

My contractor painted a waterborne acrylic enamel over my oil based enamel trim. Without sanding it. What is going to happen? The trim needs a 2nd coat but I’m afraid I might need to sand it first. I want it to be right because I am getting ready to have wood floors laid. I am right in the middle of painting the whole house.

3 Answers
crowderpainting Staff answered 6 years ago

The main problem you could encounter is lack of good adhesion. This won't occur evenly as some areas will be well adhered and other not. This is why priming is a good idea, it guarantees good adhesion throughout.

Full adhesion only occurs after complete curing of the new paint film. This takes 2-4 weeks depending on the paint.

At this point let this coat dry and cure then test for adhesion. This can be done by simply scratching with a finger nail or using a piece of masking tape; use a small piece of masking tape, apply to a "hidden" place on the trim, rub for good adhesion to the paint then quickly tare it off. If some paint comes off then there is a problem with the paints adhesion.

The only way to fix this situation is to sand off the new paint and prime before repainting.

Anonymous Staff answered 6 years ago

I called the manufacture of the Waterborne acrylic enamel paint and explained that my contractor painted over an oil base paint. They said to wait 2 weeks until it has cured. They said to scratch with a finger to check. When you scratch with you finger what are you expecting? If the paint is OK then what do I do? It needs another coat. The painter painted here and there and and slopped it on. So now it needs to be painted a complete coat of paint. What kind of paint should I use. Oil based? or ???? The manufacture said if it has a problem then I will need to sand it. But what kind of paint should I use next??

crowderpainting Staff answered 6 years ago

If the paint isn't well adhered it will easily come off by scratching with your fingernail. Give it a try and see what happens.

You can use the same water based paint to re-coat your trim but this time prime first with a good oil base primer, like Zinsser Cover Stain.

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