Painting Over Varnished Wood: Can You and How To Do it?

Varnish starts to look old after a while. So, can you paint over varnished wood?

You can paint over varnished wood, but you must strip some parts of varnish. This is because the paint will not adhere to varnish. Varnish has a higher solid-to-liquid ratio when compared to other sealants. The make-up of varnish makes it very difficult for paints to adhere.

So, you must remove parts of varnish by stress sanding before applying paint. Using acrylic paint over varnish is recommended, but oil-based paints can also work.

That’s not all. There is more to know about painting over varnish, and this post digs right into the topic. So let’s dive in.

Varnish Formula Explained

You shouldn’t paint directly over varnished wood. Varnish repels any type of paint and makes the paint adhesion difficult. Before painting varnished wood, you must remove some parts of varnish (or the entire finish). 

Varnish is common in old houses and furniture. Just like polyurethane, varnish is an old sealant. This means varnish has a more traditional formula, the finish is designed with rigid resins, chemicals, and solvents that protect the material underneath and prevent paint from sticking.

Unlike modern sealants that are formulated to be painted over, the varnish is designed to be the final coat. So, the traditional formula of varnish makes it almost impossible for the paint to be applied over. 

Varnish contains resinous compounds, solvents and has a higher ratio of solids to liquid (higher volume of solid compounds), all these chemicals make varnish super strong. These chemicals and solids also repeal paint. So, you can’t apply paint directly over varnish. 

If you paint directly over varnish, the paint will turn sticky and slide off after several days.

Why Doesn’t Paint Stick To Varnish?

Paint doesn’t stick to varnished wood. That’s because varnish when dry has a glossy finish that repels paint. Because of the moisture-resistant glossy finish of varnish, the paint can’t bite into the wood and won’t stick properly.

Varnish is filled with several resins and solvents. These compounds give varnish a super thick and moisture-resistant finish. The varnish finish prevents any liquid (oil or water) from penetrating wood, including paint. Since paint can’t get to the wood, it won’t stick over the varnish. The finish of varnish is also glossy, so the paint will slide off. 

The combination of these factors makes it almost impossible for the paint to stick to varnish. But, if the varnish is removed or stripped off, the paint can grip the wood fibers and stick well when applied.

How To Paint Over Varnished Wood?

Painting over varnished wood isn’t hard, but you must have the right tools. Here are the tools that you need:

  • Fine-Grit Sandpaper
  • Water-based Acrylic Paint
  • Latex Primer
  • Paintbrush
  • Drop Cloth
  • A Sealant

1. Prep The Wood

First, check the wood condition. If the wood is rotten, you must repair it, then paint it over. To repair rotten or damaged wood, use wood filler and fill the holes. 

2. Stress Sand The Varnished Wood

Stress Sand The Varnished Wood

You don’t need to remove the entire varnish before painting over. You just need to remove a part of the varnish to roughen it so the paint can penetrate and bite into the wood underneath.

To remove varnish from wood, use a sander or a chemical-based paint remover. Removing varnish by sanding is safer, but takes a lot of time. On the other hand, a chemical-based paint stripper removes varnish faster, but it can discolor the wood.

For this guide, I’ll recommend sanding to remove the varnish:

To sand off the varnish, use fine-grit sandpaper (220-grit). The fine-grit sandpaper is not coarse enough to remove the varnish, but it will remove the glossy layer of varnish and help paints stick better. Sand the entire finish until you can see the wood grain. 

You shouldn’t use coarse or medium-grit sandpaper as it will remove the varnish and the top layer of wood. So, it’s best to only use fine-grit sandpaper. 

You can use an electric sander to sand varnish faster. Use a random orbital sander for the middle of the surface and sanding sheets for the tight corners.

3. Sand The Wood Again

Sand The Wood Again

After sanding off the varnish, you must sand the wood grain. Sanding removes imperfections and bumps the wood has and allows the next layer to stick better. To sand wood, start with fine-grit sandpaper (220-grit) and finish with ultra fine-grit sandpaper (320-grit). 

You must remove the dust that has been produced by sanding. To remove dust, wipe the surface with a clean rag or a vacuum. If you don’t, the dust can cause bumps after you apply paint. 

4. Apply Two Coats of Primer

Apply Two Coats of Primer

Once you sand off the varnish and wood, you must prime the surface. Priming creates a smooth surface for the next paint to adhere to and hides any imperfection. 

You must use a primer compatible with the paint you will apply. For oil-based paints, use an oil-based primer and for water-based paints, use a water-based primer.

Use a paintbrush to apply 2 thin coats of primer. The first coat should dry before you apply the second one. Once the second coat of primer dries, sand the prime coating with ultra-fine sandpaper. This helps the paint stick better. 

5. Apply Two Coats of Paint

Apply Two Coats of Paint

If you applied water-based primer, use acrylic paint. If you apply oil-based primer, use enamel paint. For water-based paints, apply three coats, and for oil-based paints, use two coats of primer.

You don’t need to sand between coats of paint. Just wait until the first coat dries before applying the next one. 

6. Seal With Top Coat

Seal With Top Coat

Once the paint dries, apply a sealer. The sealer helps paint last longer and protects the paint from damage. You can use polyurethane, clear coat, or varnish. 

Related Read: Using Varnish Over Old Varnish?

Best Type of Paint To Use Over Varnished Wood

The best paint for varnished wood is water-based acrylic or latex paint. Water-based paints are user-friendly, dry fast, and have good adhesion qualities. You can also seal water-based paint with any type of sealant, including varnish, to get a high-gloss, clear, or lacquer finish. 

However, you can use oil-based paint over varnish too, but you must remove most of the varnish first. You also must apply a coat of oil-based primer before applying enamel paint. 

But, if you remove the entire varnish from the wood, you can use any type of want. That’s because you would be painting over wood and not varnish. 

However, you wear the wood material whenever you remove varnish from wood. So over time, the wood will become damaged. But with latex or acrylic paints, you don’t need to strip or remove paint. Instead, you can seal these paints to protect the wood underneath.

So not only are acrylic and latex paints easy to use, but they also improve the durability of the wood. This makes them the best over varnished wood.

Is Sanding Necessary?

Can You Paint Over Varnished Wood Without Sanding

You can paint over varnish without sanding, but the paint won’t adhere properly. That’s because sanding helps remove imperfections and creates a smooth surface for the paint to stick. If you don’t sand, the finish won’t come off smooth, the paint coating will be uneven, and the finish will have bumps.

However, if you prime the varnished wood, you don’t have to sand it. The primer creates a smooth surface and helps the paint stick better to varnish. 

Also, you can skip sanding if you use a paint with great bonding qualities, such as chalk paint. Chalk paint has impressive adhesion qualities, dries fast, and it’s easy to apply. But, you must seal chalk paint because it isn’t durable. 

But, to get the best results possible, you must sand varnish before applying paint.

Final Words

Painting over varnished wood is possible. But to get the best result, the varnish must be sanded and primed first. With the varnish sanded, the paint will stick, and the finish will come out fine and smooth. 

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