Primer Adhesion to Vinyl Sealer
A finisher gets help finding the right primer that will stick to vinyl sealer for a recoat job. August 26, 2006
I'm painting kitchen cabinets that were finished with what appears to be a brushed-on poly, done back in the 80s. A painter I know told me to TSP and shoot vinyl sealer on the cabs for the best adhesion. I did this. He then said to proceed as usual with an oil primer and then shoot my oil finish. I shot my first coat of primer and 24 hrs later I did the fingernail test to see how well it was adhering. It scraped down to the vinyl sealer. There doesnít appear to be any adhesion to speak of. I sanded the sealer, vacuumed and removed all dust with my compressor. I know I should wait 3-4 days for maximum hardness/sandability with the primer but the initial test with my fingernail and some sandpaper has me worried. Should I have used a quick dry primer that's shellac based, such as Zinsser? Any help would be appreciated.
From contributor A:
I don't see the need to seal the cabinets. If the original finish was properly primed and the top coat was aging as expected, a good primer over properly sanded paint should provide a good foundation for your finish coats. Since there is the possibility that the original paint is a poly (it may have had a hardener), I would play it safe and use primer like XIM, or XIM's UMA (urethane modified), not a shellac base.
Now to the problem at hand - chances are if you donít see any improvement in adhesion within 24 hours under normal drying conditions you wonít see any. I would guess the solvents in the primer aren't 'hot' enough to chemically bond with the sealer. These two products are not compatible. In all likelihood youíre looking at removing the primer and the sealer - I hope the painter will be there to help.
From contributor B:
You said that you scuffed your vinyl sealer? What grit? Paint needs a pretty big tooth compared to cabinet coatings. If you scuffed with anything finer than 220 then you made too slick a surface. To promote adhesion of the oil base paint add some lacquer thinner. This will thin the paint but for your first coat it is OK. The lacquer thinner will create a small chemical bite into the vinyl sealer. It won't be much because vinyl sealer tends to be slick. Yes, Bins would have been a better choice. That would also need scuffing but it is not as slick a film as is vinyl sealer.
From the original questioner:
Thanks for the information. I sanded back the one coat of oil primer and shot XIM on instead. Itís much, much better. It's tough stuff and sprayed like a dream. I think I'm in the clear. And yes, I had sanded the vinyl sealer with 100 grit. I thought that would be enough but for some reason it wasnít. One more question. Is there any paper out there that doesnít clog as fast when sanding vinyl sealer? I thought that lubricating the surface first may have helped. Any thoughts?
From contributor C:
Try using a wet dry paper, or use Norton's champagne magnum 320. It's expensive but well worth the money. We also use a lot of sanding sponges. One other trick, try using a 1/2 sheet drywall sander when sanding sealer
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