Latex primer under oil-based paint?

[merrill77]

I've got some oil-based porch & deck paint. And I have some latex-based wall primer. I know there was a post on this in the past few months, but my google-fu has failed me. The paint can says to prepare wood surfaces with an enamel undercoater. My wood already has paint on it, which I had planned to scuff/sand and them prime before painting. The target in question is a shop cabinet, which I want to look nice-ish and be durable.

Advice?

 

[Bill Clemmons]

Just curious: if it already has paint on it, why are you going to prime it? As long as you don't take it down to bare wood when you scuff sand it, I wouldn't think you need to prime it again.

As for latex under oil, I've read conflicting opinions on it. One says never do it. Another says that once the solvents have dried completely, the remaining paint is the same whether it was water based or oil based. I don't know which is correct, but just to be safe, I try to never mix water based and oil based finishes. :wsmile:

Bill

 

[boxxmaker]

I'v never had any problems,but if the topcoat says use oil base primmer,then thats the route to go.(I think):dontknow:

 

[Bas]

Hmmm, I remember something about latex paint being OK over oil-based primer, but not the other way around. But that might just be an urban legend/ folk tale/ something written on the Internet. But like Bill said, if you already have a base coat of paint, then no need to prime. If the base coat is loose/ flaking, then yes, you'd have to go all the way to bare wood.

 

[ErnieM]

I've used water base primers and oil based top coats on every harpsichord I've built for the last 25 years. I've recently switched from primers to water base gesso - again with oil base topcoats. I've never had any problems with adhesion (or anything else having to do with mixing these products). I do make certain that the primer or gesso has more than adequate time to thoroughly dry before brushing on the oil base topcoats.

Ernie

 

[Don Alexander]

latex primer under oil base paint is a bad idea the oil base paint tends to peel significantly faster than it should among other things this is assuming you are applying the primer and then the paint before the primer has time to thoroughly cure emphasis on thoroughly

and who really waits weeks/months to paint on purpose hehe

 

[merrill77]

Just curious: if it already has paint on it, why are you going to prime it? As long as you don't take it down to bare wood when you scuff sand it, I wouldn't think you need to prime it again.

Because I don't know what kind of paint is on it or how old it is, so I assumed that a primer would help it adhere better. At least, I thought that was the point of a primer. No?

 

[Bill Clemmons]

Because I don't know what kind of paint is on it or how old it is, so I assumed that a primer would help it adhere better. At least, I thought that was the point of a primer. No?

You are correct, that is the point of a primer, on bare wood. But since this wood is not bare, I think you'll be okay to just paint it. There is one other point you should be aware of: not knowing how old this piece is, are you sure the original paint isn't lead based? When you scuff sand it, please wear a good respirator just to be safe. :dontknow:

Bill

 

[Howard Acheson]

A major factor in the durability of any finishing jobs is significantly impacted by the prior finishes. Oil based enamel over an waterborne prior finish is not as durable as a finish over the proper undercoat. A general rule of finishing is to not put a hard finish (oil based enamel is hard) over a soft substrate (a latex waterborne finish is soft).

At the very least, for an unknown under coat, I would use either a Zinsser or Kilz primer. These products are intended to adhere to any finish and most any finish will adhere to them.

 

[Gofor]

I seriously doubt you will have any problem with a shop cabinet unless you have major humidity problems in the shop. If it was outdoors, subject to rain and UV, that would be another matter entirely. If you want to be a bit more safe from peeling, spray some rattle-can lacquer on the inside surfaces if you do not plan to paint them with the oil based.

If you prime with fresh latex primer, tho, you want to wait a week before topcoating with oil based. If you scuff the surface (remove all gloss and loose surface coating/dust), no primer is needed unless it is bare wood. Not priming may mean the oil based paint will soak in more in some spots, but is easily solved by a second coat. Hit the bare spots with a coat of paint first, and then recoat all after it dries.

Go

 

[jmauldin]

While I love the easy clean-up of latex, I have not had good success using latex primers, either with a latex or an oil-based paint. I just don't like them. So I'll just go through the extra time and effort to clean up the oil-based. I also agree with the recommendation of either Bull's Eye or Kilz, although I prefer the former.
Jim in Mayberry