If everything was done correctly, your polyurethane surface should be ready for paint without any issues. Water-based paint works just fine if your surface is primed correctly, however it's recommended you use oil-based paint for a more superior, long lasting finish.
Since the paint won't bond over polyurethane, it would be better to remove the finish with paint remover or sand it down thoroughly, effectively etching the surface of the polyurethane until there's no sheen left. Then it would be best to use a primer first before final painting.
Apply either oil-based or water-based polyurethane with a brush, lambs-wool applicator, or lint-free cloth.
In addition to being waterproof and resistant to shrinkage, polyurethanes are sandable and paintable, making them suitable for a wide range of home improvement and construction applications. As a rule of thumb, oil and latex paints are ideal for this particular type of sealant.
Hey, so here's my take on this question… Yes you can paint on top of polyurethane, you could use latex or oil based paint. But you would need the poly to be in good condition, ie not all cracked, flaking, peeling it would need to still have a good “bite” on the surface below.
Sand the surface to remove polyurethane.
You can simply use fine steel wool. You can also use 150-grit sandpaper. The sandpaper will smooth it out and take off the last of the polyurethane. The after wash should have taken off most of the polyurethane, which is why you shouldn't need a heavy-duty sandpaper.
Natural bristle is the best choice for oil-based paints, varnishes, shellac, alkyd enamels, oil stains and oil-based polyurethanes. The highest quality bristles come from mainland China. Experienced, traditional painters will say there's nothing like the finish that a China bristle can provide for oil-based coatings.
Polyurethane kitchen durability
The durability of a polyurethane kitchen is also very good. Polyurethane kitchens have a great resistance against chips and scratches.
You can use a brush, rag or spray for your project. The best way to apply polyurethane will depend on the surface of the wood project. Brushes are best for flat surfaces such as tables or some chairs. Brushing a rounded, contoured or vertical surface is more likely to create drips.
You can try painting directly over a polyurethane finish with any type of paint, but it's very likely to start peeling off over time. If you aren't stripping the polyurethane, priming the surface and using an enamel paint is likely to going to give you the best results.
Understanding Deglossers: What is a Deglosser? Deglossers, often referred to as liquid sandpaper, are chemical solutions designed to remove the glossy finish from surfaces without the need for physical sanding.
Apply oil-based paint primer. Using a primer will give your paint a better surface to stick to. The primer also keeps any stains on the wood from coming through the paint.
MAGNOLIA HOME BY JOANNA GAINES® TRIM, DOOR + CABINETRY INTERIOR SEMI-GLOSS PAINT 4.5 out of 5 stars, average rating value.
If you don't mind a little variation in texture, 3 coats of poly should be more than adequate. Sand lightly after each coat as dried and dust thoroughly before applying the next coat.
PU for a refined appearance
PU finish allows you to choose any colour you want. PU finish is painted over the shutter and can be glossy or matte. The only disadvantage of PU is that it takes a bit more time to dry relatively, however it provides unrivalled shine and protection to your kitchen shutters.
Vinegar breaks up the grease without damaging, causing any abrasion to the polyurethane. Because vinegar works like a glass cleaner, it also won't cloud the finish like other cleaners and can break through any buildup.
Wetting your brush before applying polyurethane is not necessary and can actually hinder the application process. Instead, ensure your brush is clean and dry before dipping it into the polyurethane.
Use a Roller on Large, Flat Surfaces
rollers lets you apply the poly fast and evenly. No brushstrokes, puddles or thin spots.
A roller is the recommended method for applying some water-based polyurethanes, as well as some oil-based polyurethanes and moisture-cured poly finishes. Rollers are good for finishing multi-direction floors, like parquets.
When you use vinegar on polyurethane finished wood, the acid in the vinegar breaks down the finish and starts to pit the finish. These pits trap sand and along with the acid will eventually strip the polyurethane.
Enhanced Durability
Polyurethane acts as a protective coating, helping to minimize the appearance of scratches, dents, and general wear. This hard-wearing finish is particularly suitable for families or high-traffic kitchens, ensuring that your cabinet doors maintain their integrity and appearance over time.
Acetone is far from the only option available if you want to remove polyurethane. Many people use sanding strips, sanders, or metal scrapers to gradually remove the substance. You might also opt to use a planer, which trims the surface to expose the bare wood underneath. Chemical strippers are another popular option.