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A buddy of mine uses Lenmar precat lacquer sometimes on his painted cabinets. He is having a problem on a job where the bumper pads are pulling the paint off the cabinet down to the primer. The primer is a Chemcraft white vinyl sealer. The bumper pads are made by 3M. The cabinet faces have been drying for several weeks before the doors were attached. Does anyone have an idea as to what the problem may be?
1. Is the primer scuffed prior to top coating?
2. What grit is the scuffing?
3. How thorough is the scuffing? 100% coverage of the scratch pattern?
Let's assume that there's a good scratch pattern to the primer, and it's 320 grit. The precat takes about 3 - 4 weeks for it to fully crosslink, which is what it does with all deliberate speed (i.e., slowly). Put the bumpers on after those 3 weeks of crosslinking and peel one off to see if there's still an issue with intercoat adhesion of the top coat and the primer.
If the issue persists, get an SDS for the bumpers to see what's in the adhesive. The bumpers themselves are made of vinyl, so plasticizer migration from the bumper to the finished surface is always going to be something to be weary of.
The problem is not with the pad adhesion to the doors. The problem is where the pads make contact with the frames. Opening doors cause the finish to be pulled off. Primer is scuffed with 220 sanding pads.
Several reasons for poor adhesion. Bad batch of finish or old batch (precat has a definite shelf life), put into use before complete curing (a big difference between dry to handle and cured), incompatibility with undercoats and top coats, undercoats not completely cured before top coating, hard closed cell wood like hard maple was sanded too finely before coating, etc....
My money is on: Primer was sanded entirely too smooth and possibly not scuffed the day of painting thus making it close sanding scratches up even further... Plus like most of us a heavy handed finisher to give those doors a nice full wet coat of over millage topcoating….. resulting in a topcoat that takes much much longer to cure properly as well as a substrate that was not mechanically or chemically bonded well... thus resulting in paint sticking to bumpers and peeling from the primer layer....
Is the damage occurring at all or most of the bumpers?