I have a repeat customer who wants cabinet doors re-sprayed. They are Kraft-maid and they don't need stripped or re-stained, just top-coated. They are 15 years old and the top-coat is wearing. My question is with ML Campbell products, should I put vinyl sealer on first or can I put Krystal right on top?
From contributor S:
Do a light coat of vinyl sealer. Then you can do your Krystal after scuffing the vinyl sealer. Do not expect to get the high performing durability of Krystal with this recoat.
Here's why. Your new topcoat can only be so many dry mils thick because for Krystal you cannot have a total coating weight that exceeds 4-5 dry mils. An application of Krystal that is 1-2 dry mils has nowhere near the performance and durability of a Krystal coating system that is through-and-through 4-5 dry mils.
You do not know the amount of existing dry mils of finish. I suggest that you clean your areas to be recoated with a mixture of TSP and water. Rinse with clean water. Scuff real good with 280 grit or 320 grit stearated sandpaper. Lay down a thin coating of vinyl sealer (you can shoot anything from unreduced 25% solids to something cut in half at 12% solids). Scuff with 320 and lay down one coating of Krystal.
Now you are done. No guarantees on the behavior of your new coatings or its durability or performance. The only aspect of the whole operation is that you can predict how you want it to look in the end, not even how long the coating will last.
I should have mentioned first that if your original coating is wearing in such a way that it is starting to degrade, chip and peel then you are too late for a recoat. Degraded finishes should not be recoated. They should be stripped.
I wouldn't try cleaning them with anything lest you push what's there around and make it worse. Your best option in my opinion is to choose a waterborne you want to use as a topcoat and apply it correctly (light scuff with 320 or even Scotchbrite unless you're using a urethane which may require a sealer and a heavier grit sanding). If it fisheyes you will know within a few minutes if not instantaneously and at least you'll have a decent chance at wiping it off with a really wet rag.
The only problem here could be that the contaminants migrate over 24 hours and you won't have time to wipe. I'd like to tell you to just go for it and maybe you will and if so I hope you don't have a problem. If you're at all worried by my suggestion (which I make because it happened to me and caused me grief) that adhesion could be a problem then at least brief your client and do a test. What's the worst that could happen? You could end up having to match/replace every finished surface on the kitchen.
Using "softer" solvents like retarders in the new coating can be a big help in preventing wrinkling and separation in the recoat. There are plenty of areas where you can do your testing on the cabinets, and barrier coatings are another option you can consider. Recoating is not for every shop. If you’re going to do recoating, you need to do your homework on each and every job you do.