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.