Always sand the polyurethane before painting. If you don't invest time in sanding, your paint over polyurethane project won't be a success. Although these how-to painting steps are for kitchen cabinets, they also can be applied to wood floors, doors, or furniture that have a polyurethane finish on them.
Sanding The Wood Surface
Sanding is one of those things people either love or hate, but whatever the case, many experts will agree it's an extremely important step if you're painting over polyurethane and you want your paint to stick properly. For smooth surfaces, you'll want to go coarse with 60- or 80-grit sandpaper.
You can, but you'll need to use a good primer first. Polyurethane creates a slick, plastic-like finish that most paints won't adhere to. A bonding primer will stick to the polyurethane and create a surface that's just textured enough to paint over easily. Think of primer as a glue.
Even freshly finished cabinet doors won't look good if the cabinets are too worn or damaged. If it's just the finish or the hardware that's worn, but the wood itself is still solid, you should get good results from painting kitchen cabinets.
Before you paint varnished cupboards, you must remove the high-gloss finish. You may do this either of 2 ways: Take an orbital sander to cabinet surfaces you plan on painting, and sand them down until they are no longer shiny. Wipe the dust off with tack cloth.
“Oil-based paint is the preferred formulation for cabinets due to its leveling qualities while painting, and stain-resistance and clean-up once they're in use,” says Hathaway. “Latex paint offers easy cleanup but doesn't have the ease of care that oil-based paint offers.”
Keep reading to find out the best way to get rid of that varnished wood and have your home looking fresh. Many people believe you can't paint over varnished wood. This however is false. In order to paint over it you will need to use either oil or water-based paints.
As long as the surface is stable and in good condition, the cabinets do not need to be sanded. Proper cleaning, deglossing, and using good-quality cabinet paint are key to painting cabinets without sanding.
Don't Go Overboard on Sanding
You should sand cabinets before beginning your how to paint kitchen cabinet project to give the new paint a good surface to grip. But you don't need to sand to bare wood. If your cabinets have a factory finish, sand lightly with 120-grit sandpaper or a sanding sponge.
Just roughing up the surface with fine grit sandpaper is enough to get the paint to stick to polyurethane. With a little elbow grease, you'll be ready to paint in no time! Sanding is especially important if you plan to stain the wood a different color instead of painting it.
A thin coat of bonding primer is going to be an essential ingredient to painting over polyurethane. Applying a good quality primer can help to prevent tannins from bleeding through your paint and ruining the overall color.
An oil-based primer is the only type of primer that is compatible with your polyurethane finish.
You can remove both oil- and water-based polyurethanes from wood surfaces using paint stripper, denatured alcohol and lacquer thinner, or baking soda and vinegar.
A polyurethane varnish finish can cut down on the wear and tear of kitchen cabinets, help keep them looking new and extend the life of the cabinets. Polyurethane works best on unfinished wood but can also be painted directly onto painted surfaces.
You can paint over varnished wood as long as you use the right materials and painting process. The best paint to use is a water-based acrylic one. If you're using an oil-based paint only use an oil-based primer, not an acrylic one.
We recommend using Zinsser Bulls Eye 1-2-3 for glossy surfaces like varnished wood.
GF Milk Paint is incredibly high-quality acrylic paint with EXCELLENT adhesion (so good that you can even paint laminate cabinets with it). It has low VOCs and is incredibly durable, so it is a great choice for painting kitchen cabinets without sanding or priming. It also really minimizes brush strokes!
But if the doors are smooth (not slick) to the touch, you can likely skip the sanding step, as long as you do a few bits of prep first! If you don't want to sand before you prime, use some mineral spirits and a rough sponge to clean and lightly rough up the cabinet area you're painting.
Even oil-based acrylic paints will have a hard time sticking to a varnished surface. So you either have to apply a primer before painting the wooden surface or you have to sand the surfaces in order to give the paint some tooth to stick to.
Polyurethane is considered the top tier of cabinet finishes. It is a two part paint mixture of resin and hardener, similar to that of automotive paint used on cars. It is sprayed onto melamine covered moisture resistant, medium density fibre board (MDF) on doors, drawer faces and panels.