Painting over varnish is not as simple as painting on primer and top-coat, for the reason that varnish is a slippery surface. Therefore, prepping and priming the surface involves about 80% of the job.
What you need:
- Any of the following: sandpaper (80 to 100 grit), electric sandpaper, liquid sandpaper, TSP
- Primer
- Semi gloss paint
- Paintbrushes
- Rags or towels
- Masking tape, old newspapers, and plastic sheets
- Work clothes and mask
Roughen the surface. The first thing you need to do when painting over varnish is to roughen the surface. As it is, primer will not attach to varnished wood, because of the smooth surface. You will need to scratch it up, in order for primer to adhere to the surface. There are several ways of doing this, and it will usually depend on your skill, and the availability of the tools and materials.
The simplest way is by means of sandpapering. Use 80 to 100 grit sandpaper to roughen the entire surface you want to paint on. If you have an electric sander, or a dual-action polisher with a sanding attachment, you can use this to roughen the surface.
Alternatively, you can use several solutions that will be abrasive to glossy surfaces. Some examples include TSP and liquid sandpaper. Results might vary, though, so it might be a good idea to try applying this on a small area initially. If all else fails, you can resort to good old sandpaper and manual labor.
Be sure to clean the surface of any debris before applying primer. You might want to fill in holes and dimples with wood putty at this point. These surfaces should also be sanded prior to priming.
Apply primer. Once the surface has been roughened, you will now need to apply primer. Usually, one coat is enough. Let this coat dry for two to four hours. However, if the wood grain is still showing, you will need another coat. How many layers of primer to apply will depend on whether you want the wood’s natural grain to show after painting.
Paint over the primer. Use semi gloss or eggshell paint to layer over the primer. Let the first layer dry for about four hours, and then add another layer.
Be sure to wear a protective mask and goggles when sanding, especially if you are using an electric sander. While painting, use work clothes, such as old shirts and jeans, or overalls. You wouldn’t want to ruin your street clothes with paint and abrasive chemicals.
Varnished wood does have its own classic flair. However, a modern touch would usually require smooth, bright surfaces. Painting over varnished wood is one good way to achieve this effect.
