Is it true that oil based can go over latex?

Sasha2000

An old painter told me the other day that you can paint oil based over latex, but not the other way around (at least not without a lot of trouble). Is this true?

poppameth

I've always been taught the exact opposite. Generally you can put just about anything over a universal primer whether it is oil or latex. If you put oil over an old latex, even if it is sound, a lot of times it will peel since oil grabs so hard to it. Latex over oil can have issues adhering unless you use the proper type of product that can stick fine to an oil finish. That said, some of the newer acrylics are so aggressive now that they bite harder than oil and can even cause old oil base to peel. I've mainly seen this on old roofs with too many layers of paint.

Nestor_Kelebay

You can paint either oil or latex over either kind of primer.

When it comes to painting over paint, then my understanding is that you can paint an oil based paint over a latex paint, but not the other way around unless the oil based paint is a flat paint (in which case it's rough enough for the latex to adhere well).

If you want to paint a latex over an oil, the normal procedure is to apply an alkyd primer first over the oil based paint, and then paint the latex over the primer.

Also, with either kind of paint, you need to rough up the surface of a semi-gloss or gloss paint before painting over it with the same kind of paint. The purpose in doing this is to increase the surface area between the two films to increase the adhesion between them.

slickshift

Yes
A bit of oil based primer would solve the 'trouble' for "the other way around"

Sasha2000

Thanks for the reminder about primer. I always seem to get lucky and just paint a new coat with a light sanding. But I need to pay attention to the 'basics' and start using primers again. Thanks for the info.