Wood sealer is the best way to protect your wood projects from elements and general wear and tear. You may also want to update the color of your project with a beautiful coat of paint.
But can you paint wood after sealing it?
You should not paint over wood sealer. While it is possible, most woodworking experts do not recommend it. Wood sealers are designed to repel moisture, so paint will not adhere properly to them. Many wood sealers also do not adhere well to painted surfaces, so you should not apply them after painting, either.
Should You Paint Over Wood Sealer?
No, you should not paint over wood sealer.
Wood sealer is designed to fill in and harden the wood’s surface, stopping anything else from penetrating.
This prevents the wood from absorbing unwanted material and becoming damaged. It can even protect your projects from UV rays.
It is the ideal product for extending the life of your otherwise unfinished or raw wood projects.
However, sealing wood before painting will not look as good or last as long as alternative painting and sealing methods.
What Happens If You Paint Over Wood Sealer?
Painting over wood sealer can lead to the paint flaking, cracking, and peeling.
A wood sealer’s main purpose is to prevent other materials – water in particular – from becoming absorbed into the wood. As such, the paint will not be able to “grip” onto the sealed surface.
At best, the coats of paint will not last as long as they would on a surface that was primed for paint or even on an unfinished surface. At worst, you’ll have trouble getting a base coat of paint to stick in the first place without cracking or bubbling.
Even applying a paint sealer on top will not fix the poor adhesion to the wood sealer beneath.
How to Paint Over Wood Sealer
Applying paint over wood sealer should be a last resort for your wood projects.
In theory, it is possible to get a decent paint job over wood sealer, however. You can let the sealer cure for an extended period, then apply a base coat of paint primer.
However, this is not widely recognized as viable and is very time-consuming; the curing period needed for the sealer to potentially accept a base coat is anywhere from one to six months.
It’s a much better idea to find alternative methods to add color to your projects, or to simply leave sealed wood unpainted and unstained.
Alternatives To Painting Over Wood Sealer
There are better ways to spruce up your wood projects besides trying to paint over wood sealer, and a few of these methods can even offer some of the same protection, even if to a slightly lesser degree.
Painting Over Unsealed Wood
If your project has not already been sealed, feel free to paint away. The recommended method is to use a paint primer first, then your chosen colored paint.
There are some paints that even have a primer built in, saving you a step. For maximum protection, use a sealer designed for paint to finish.
A paint sealer doesn’t offer the same amount of protection that a wood sealer does, but it does help to extend the life of the paint, if not the wood beneath.
Using paint in addition to primer over unsealed wood allows for a wide variety of colors and styles. Be sure to choose a primer and a paint sealer that are designed to work with your chosen type of paint (oil-based, latex-based, etc.).
You can also stain your unfinished wood projects to give them a different color, but in a more natural-looking way than paint.
You will also need to seal the wood after applying the stain, as most stains offer very little protection. Use a sealant designed for your chosen type of stain or use a stain that specifically states that it protects wood.
This method is more limited in the range of styles than paint, but because the stain penetrates the wood rather than sitting on top, you can use certain types of wood sealer over it to enhance protection.
However, once you apply wood sealer to bare wood, you can’t use a stain over the sealer. Just like with paint, the sealer will repel the stain that will just sit on top of it rather than penetrate.
Removing The Wood Sealer
If there is wood sealer already on your project, your only option would be to remove the sealer by either sanding it down or using a sealer stripper product; in particularly stubborn cases, you may have to use both methods.
Then you can use one of the above methods on the fresh wood surface to upgrade its appearance.
Types of Wood Sealer
There are several different types of wood sealer, each offering different benefits for particular projects.
Be sure to read the label of any product before purchase to ensure it’s appropriate for your needs. Some of them work best for indoor surfaces, while others may work better with different types of wood.
Polyurethane is a synthetic, water-resistant sealer. The two main types are water-based and oil-based.
A water-based sealer is best for decorative finishes and is fast-drying. Oil-based polyurethane dries slower and is best for furniture.
You can even use polyurethane over top of paint, although the oil-based variety is prone to discoloration when used over paint.
Many types of polyurethane are indoor-use only, and require certain precautions to use safely. If working with wood outside, you should choose a product that specifically states that it’s for outdoor use.
Lacquer is another synthetic sealer and is one of the most durable, offering a wide range of finishes from matte to glossy.
It is applied in a thin coat that dries quickly, and it is usually sprayed rather than brushed onto wood.
This makes it a little harder to apply than other types of sealer, as it can require special equipment. Lacquer works best when applied to stained, unpainted, and otherwise unsealed wood.
Shellac is a natural insect resin that is mixed with alcohol to form a liquid sealer. It offers a hard finish to both bare and stained wood.
Do not use it for high-moisture areas or areas exposed to alcohol spills, as they will break the shellac down over time.
Sanding sealer is a basic sealer with the addition of zinc stearate. Zinc stearate is a type of soap that is much faster at building up sealer and filling in pores.
Because of this, you need fewer coats of sanding sealer than you would with any other type.
The zinc stearate also tends to make the sealer softer; this makes it easier to sand away, but also means it’s no good for more than one or two coats.
It should also not be used underneath a more brittle sealer, such as lacquer without zinc stearate.
Do you need to seal painted wood?
To extend the lifespan of your painted wood projects, you need to use a sealer on top of your paint.
Use a product specifically designed not only for paint, but for the specific type of paint you used.
Without a paint sealer, your project will have little protection from UV rays, wet weather, or the damage that comes from normal use.
You are more likely to have to repaint a project in a shorter amount of time if it does not have sealer.
How do you seal painted wood for outdoor use?
There are sealers specifically designed to protect paint during outdoor use. Each product will come with its own instructions, but in general, you apply the sealer once the topcoat of paint is dry.
Most sealers will require more than one coat before the project is ready for outdoor use. For the best results, each coat of paint and sealer should be completely dry before you apply the next coat.
Can you put wood sealer over paint?
Except for polyurethane, wood sealers do not adhere well to paint. As the name suggests, their purpose is to seal wood specifically.
As with painting over sealer, it is technically possible to use wood sealer over paint, but it is not the best option.
You should use a sealer designed for paint instead. If you choose to use polyurethane, select a water-based product and read the label to ensure that it’s appropriate to use over paint.
Conclusion: To Paint Or Not To Paint?
While painting your wood projects can certainly add to their visual appeal, the most important thing to be concerned about is their lifespan.
There’s no point in having a beautiful white deck if the wood becomes weather-damaged and the white paint itself begins to peel or crack.
In short, you should not paint over wood sealer. Although technically possible, there is no guarantee the long-term curing method will work well.
It also takes a lot of time and effort, and simply will not last as long as other beautifying methods.