For many DIYers, woodworkers, and furniture repair enthusiasts, a wood sealer is a must. Especially if you are working on projects that will spend most of its’ life outdoors in wet or humid weather. Keeping this in mind, can you paint over wood sealer?
Painting over sealed wood will result in bubbling, flaking, or chipping. Because sealants are created to seal out moisture and create a protective coat, the paint will not adhere to sealed wood materials. Most paints do contain a small measure of sealant. However, in most cases, wood needs to be primed before being painted. Use wood sealer after painting for stronger protection from outdoor elements.
Not all treatment options for wood, painted or not, are created even. It all depends on the type of wood, the environment in which the wood will be stored, and the desired cosmetic outcome. All of this and many other factors play a role in how to care for wood properly. Below, we will discuss different treatment options, alternatives, do’s and don’ts, what to use, and how to prepare wooden surfaces before painting them.
The huge variety of finishes for furniture is one of the subjects we will be diving deeply into during our live online workshops at Cucamonga Woodworking and you can check out our past workshop YouTube videos Here(Link to Cucamonga Woodworking)
What are paint primers?
Wood paint primers are transparent chemical substances applied to untreated wood surfaces to prepare the wood before painting. Using wood paint primers increases the paint’s durability and improves the paint’s adhesion to the wooden surface.
The type of paint primer is usually determined by factors like wood type and the intended paint type. Paint primers are recommended before applying paint on interior and exterior surfaces, enhancing the paint film’s life.
Different types of paint primers and when to use them
Before applying any paint primer to wood, you need to prepare the wooden surface first. This usually involves you sanding the wooden surface with a minimum of two different sandpaper grits, 100and 150 or higher. Then, scour the wooden surface with steel wool or a scouring pad to remove sawdust.
After that, Wipe it down with a damp, non-fiber cloth and wait for it to dry. You are now ready to apply your paint primer. There are three main types of paint primers used on wooden surfaces. Below we will list all three, along with how and where to apply them.
Oil Based Primers
Oil-based primers are suitable for both interiors and exteriors and are mainly used for woodwork. Oil-based primer is also known as alkyd primer and suitable for use with oil and latex-based paints.
This type of primer can remain flexible after drying, making it useful in climates with unpredictable weather. It takes a long time to dry, 24 hours or more. But is known for its ability to cover stains. To thin oil-based primers, you need to use mineral thinners. Oil-based primers contain VOCs or volatile organic compounds that can be toxic if exposed to long periods, so be sure to use a mask when using them.
Shellac Primers
Shellac primer is the last on our list of primers. It can be used with both latex and oil-based paints. It dries very quickly, generally under an hour, and is best used for outdoor applications to block out water stains and smoke damage to walls. It can be used on wood, metal, plaster, and plastic.
Latex or Acrylic Primers
Latex Primer or acrylic primer can be used on various materials, including wood, plaster, masonry, and painted metal. This type of primer is water-based and generally used with acrylic paints.
It contains low to no VOCs and is a healthier alternative to oil and shellac primer. Because it is water-based, we advise caution when applying it to untreated wood as it may raise the grain. This is not a bad thing, as it can provide a flexible finish that is resistant to cracking. It dries very quickly, usually under three to four hours.
How to paint and seal wood without primer
As outlined above, it’s advised to use a paint primer before painting and sealing wooden surfaces. However, If you find yourself in a tough spot and only have oil-based paint and wood sealer on hand, you can get away with using applying it in the right order.
First, prepare the wooden surface the same way you would before applying primer, using three sandpaper grits and a steel wool pad to remove any excess sawdust. After cleaning the wooden surface with the damp non-fiber cloth, you can use the paint directly to the wood. After ensuring the paint has dried thoroughly, you can apply the wood sealer. We recommend sticking to an oil-based sealer.
Different types of wood sealer
There are primarily two types of wood sealer, water-based and oil-based. Both products can be used on raw wood but have different cosmetic finishes.
Water-based wood sealers are the more popular of the two because of the quick drying time. They are also less toxic and odorous than oil-based wood sealers. However, water-based wood sealers also require multiple coats to be applied to be effective and can be more expensive than oil-based wood sealers.
Oil-based wood sealers require fewer coats to finish but take longer to dry and cure. In addition, These wood sealers often contain toxic compounds known as VOCs or Volatile Organic Compounds. Now before you panic, these compounds are only dangerous to you if you breathe them in and expose your skin to them regularly.
The VOCs are also the chemicals that cure, bind, and forms the protective layer over your wood. If you are still uncomfortable, there are low VOC oil-based wood sealers available on the market.
A well-kept secret for a fantastic wood finish is to combine both oil-based and water-based wood sealers. The oil-based sealer will have to be applied first, left to cure for a good while, and then you may apply the water-based sealer. This will give you a beautiful finish.
How to apply wood sealer without paint
The procedure for both oil and water-based wood sealers are more or less the same. Depending on the type of wood, however, you will apply less or more.
For most softwoods, you would start with sanding the wood with a rough grit of 80 first and then secondly with a grit of 120. After you have finished sanding the softwood with the 120 grit sandpaper, you use steel wool or a scouring pad to remove the dust and excess wood particles and then wipe with a slightly damp non-fiber cloth.
You are now ready to apply the first layer of wood sealer. If you opted for the water-based wood sealer, you would have to apply three to four coats for the optimum finish. Wait until each coat is thoroughly dry before applying the next. With an oil-based wood sealer, you can only use a couple of coats, waiting until the first is thoroughly dry before applying the second.
Hardwood surfaces need to be sanded as well before applying either type of wood sealer. The process is the same but tends to take longer because of the density of hardwoods. The application requirements for hardwood surfaces tend to be less as the sealant does not need to penetrate as deeply as with softwoods. This means that you can get away with one coat of oil-based sealers and two coats with a water-based wood sealer. As with softwoods, you have to wait for both types of sealers to dry thoroughly.
Can you paint over varnish or lacquer?
It is not recommended to paint directly over either varnished or lacquered wood as they are both alternative wood treatment options meant to add cosmetic value to wood. In addition, painting directly onto varnished or lacquered wood will cause the paint to peel off and not adhere properly. However, if you remove the varnish or lacquer from the wooden surface with a sander and Trisodium Phosphate cleaner, you should be able to apply paint to it. Remember to use a primer before applying the paint, though, which will help the paint adhere.
Conclusion
As we have discussed, painting directly onto a wood sealer is almost always a bad idea. If you wish to protect the wood and extent its life, it is better to use the proper paint primers. We recommend sticking to oil-based paint for convenience or acrylic-based paints if you are painting in an enclosed space. Applying the correct corresponding wood sealer afterward can add even more protection and extend the paint’s life. If you have any doubts, always refer to the experts at your local hardware store.