On average, depending on what type of sealer you use, it takes a wood sealer between 5 minutes and between 8 and 24 hours to feel dry to the touch. However, it can take as long as 30 days to completely cure to be thoroughly dried and set enough to place furniture on top of it.
Either way, you can usually walk on the floor without shoes after about 24 hours without worrying about damaging the look of the floor. The drying time depends on a number of factors including the type of wood and type of sealer as well as the drying environment and humidity levels.
Factors That Affect Drying Time
There are a number of factors that affect drying time for wood sealers. The temperature and moisture content of the air has a dramatic effect on drying time. The type of wood, type of sealant, solvents, and additives also change the rate at which the finish will dry.
Additionally, the method you use will also change the amount of time needed to dry.
Moisture or Humidity
The irony is that you are applying the wood sealer to protect the underlying wood from water or moisture damage as well as to make the wood look great and bring out the grain. However, it’s the same water and moisture that may extend the drying time of the sealer.
The more humidity or moisture in the air, the longer it will take to dry.
Type of Wood
The type of wood will also change the drying time. Some woods actually produce natural oils or substances that will delay the curing time of the sealer. Rosewood and aromatic cedar fall into this category of natural oil-producing wood.
The secret to a shorter drying time is to first sand it well. If the wood is sanded properly, it will have an open grain surface that absorbs the sealer to make it dry quickly.
Type of Sealer
The type of wood sealer makes a big difference. Some finishes feel dry to the touch almost immediately, and others take longer. The sealer is dry when the surface feels neither sticky nor appears to be wet. Some sealers are not fully hardened when they appear dry and must go through a process called curing.
Sealers like shellac, lacquer, or varnish all form a film and are considered to be a buildable finish. A buildable finish means that each coat dissolves into the one below it. It may take several layers to achieve the level of protection and look you want.
Each layer will need to completely dry before moving on to the next layer.
Varnish, Polyurethane
Varnish or Polyurethane – Polyurethane is a synthetic resin and type of varnish that come in either water-based or an oil-based form. Varnish and polyurethane will take a long time to dry and cure. While it will usually feel dry to the touch after 24 to 48 hours, it can take a month to properly cure.
Both oil and water-based varnish will require curing. It may be worth the wait, however, because the finished results will be very hard, tough, and durable.
Damp conditions will slow the drying time of varnish. A low-humidity day is best for applying varnish, even for inside work. If this is not possible, set up a dehumidifier. Varnish will cure best at temperatures near 70 to 75 degrees F, 21 to 23 degrees C.
If it is too cold, the varnish may not cure at all. If the temperatures are too hot, the varnish may dry too fast and potentially ruin the end results with bubbles and cracking.
Polyurethane thinners that contain evaporative solvents are sometimes added to varnish to speed up the drying time but will not change the amount of time needed to cure.
Oil-based varnish or polyurethane will feel dry to the touch within 24 hours and be ready for a second coat. It will be fully hardened after 30 days.
Water-based varnish or polyurethane will feel dry after 6-8 hours and is ready for a second coat when the first coat feels dry. It is fully hardened in about 20 days.
Water-based varnish is often used because of the low odor and low VOC off-gassing as well as the shorter dry time. However, when you use water-based varnish you may forfeit some of the final appearances you are after, as it tends to flatten the grain.
Water-based varnish is also more susceptible to temperature, drying very fast in hot temperatures above 80 degrees F, 26 degrees C. To remedy this, you can use a dry-time extender.
Set items on varnish or polyurethane after two days, but wait to place rubber mats or other plastic items
Lacquer
Lacquer will feel dry to the touch after about 5 to 15 minutes and is ready for a second coat in half an hour. It will be fully hardened in one week if it is applied in a well-ventilated area.
Lacquer is fast drying, but feeling dry to the touch does not mean it’s fully hardened. Lacquer is a non-curing finish, so it will dry through evaporation of the solvents which may keep evaporating for days or as long as a week.
Before using it, lacquer should be buffed to create a smooth, high gloss look. If it starts to form tiny balls when you begin buffing, it’s not yet completely dry.
Shellac
Shellac consists of resin and denatured alcohol. The ratio of each will determine the thickness, also called the cut.
A heavy cut is made of less denatured alcohol and will take longer to dry. The opposite is true of a lighter cut. You can change the amount of denatured alcohol to adjust drying times.
Shellac is a non-curing finish, so it will not harden more after it dries. You can set items on the finished piece two hours after the final coat.
Shellac is great for sealing in odors. It will feel dry to the touch in 5 minutes or less and be ready for a second coat in 30 minutes for the early coats and two hours for later coats. Allow a 12-hour rest for every three or four coats.
Shellac is fully hardened in 2 hours. If your brush or polishing pad drags on the surface when you go to apply another layer, the shellac was not fully dry.
Apply shellac at temperatures of 40 degrees F, 4.44 degrees C, or higher for better drying results.
Penetrating Oil
Penetrating Oil Finishes feel dry to the touch within 6 to 8 hours and are ready for a second coat when the previous coat is dry.
Tung oil or linseed oil are a couple of the most common penetrating oils. These oils make it easier to spread and speed the dry time.
To be fully hardened will depend on the formulation. With a penetrating oil finish, it will seep into the pores of the wood and form a flexible stable barrier instead of building a thick layer on the surface. After the oil soaks into the wood for 5-10 minutes, wipe off excess oil. Within 6-8 hours, the wood should be ready for a second coat.
Application Method
Apply the sealer of choice using either a brush, a sponge, a rag, a roller, or by spraying it on. How the sealer was applied will make a difference in how long it takes to dry.
If you put too many coats on or add a new coat before the first one is completely dried, it could leave it looking uneven, develop bubbles, collect dust, or loose fibers from the air, or show brush marks.
Ways To Increase Drying Time
There are several methods to use that will speed up drying time. Some of these methods include:
- Adding a compatible drying agent such as thinners with evaporative solvents
- Using a space heater
- Turning up the thermostat
- Using a dehumidifier
- Using an indoor air conditioner to lower the humidity level
- Using fans, both portable or ceiling fans help
- Creating ventilation by opening windows
What about sanding and buffing?
Sanding can be used to prepare the wood for sealing or during the sealing process. Buffing or screening is done to smooth out minor rough spots or in between layers of polyurethane once each layer has completely dried.
To prepare the wood to be sealed, use a hand sander or an electric sander to smooth out any rough spots or imperfections in the wood. If the wood is rough, start with a rough sanding grit of 100-120, 115-162 micrometers, and progress to a finer grit gradually. Finish off by using 400-grit, 25.8 to 36 micrometers, sandpaper for the final buffing.
Even if the wood seemed to be very smooth from the start, always go over it at least once with 400-grit, 25.8 to 36 micrometers, sandpaper to make sure it’s ready to be sealed.
Always sand with the grain. In other words, move the sandpaper back and forth along the natural lines of the wood. Do not go against the grain or use a circular motion, or you will leave swirling marks that may show up even after the wood has been sealed.
Always wear a dust mask and goggles while sanding to avoid inhaling dust particles or getting wood specks in your eyes. When you are done sanding, wipe the wood clean using a dry cloth.
Final Thoughts
It may take as little as 5 minutes before some sealers feel dry to the touch but up to an entire month before they are completely cured and ready for use. Most sealers require additional time to completely harden or cure before you can safely place items or furniture on top of them.
How long it takes for a wood sealer to dry will vary drastically depending on the type of wood and the type of sealer you use as well as other factors.
Safely speed up the drying time if necessary by using various methods, such as proper ventilation, heat, fans, dehumidifiers, or compatible drying agent additives.