03-05-2013 05:30 PM
Here's a question about paint that came to us on the Apron blog:
"Can you use enamel paint over a water base primer/sealer? If not, is there a easy way to get primer off and redo?
I'm a writer and editor for The Home Depot's Apron blog.
03-05-2013 11:22 PM
Home Depot Craig,
The question states "enamel" and I assume the questioner is talking about oil enamel, although that term can also encompass water based enamel products. In either case, when talking about interior surfaces, the answer is yes.
Oil and water products are compatible once thoroughly dried. The relatively flat finish of primers lend themselves to good adhesion.by the top coat. Water based primers have been used for years as the primary primer over drywall. Oil and epoxy finish coats can then be put over it. Of course, so can water based finish coats.
If talking about exterior surfaces, there is some debate about the wisdom or switching water based and oil products. Exterior surfaces are subject to wide ranges of temperature, radiant heat from sunshine and humidity, to which interior surfaces are not. Oil paints are very hard and britlle and become more so with age. Oil also has a very low coefficient of expansion. "Latex" or acrylic paints expand greatly under these elemants. Therein is the debate about the advisability of mixing the two: Should you bind two surfaces together which are expanding at different rates?
It is best to avoid the question and stick with one or the other on exteriors, especially if a house has had oil for decades.
A poorly bonded oil finish can be ripped right off the siding by a well bonded acrylic paint which is schrinking as it dries! There are paint strippers on the market that use this phenomenon to break the bond of old exterior finishes - they bond then schrink causeing massive peeling!
Hope this has helped.