Can’t make a choice between sanding sealer and polyurethane for your project?
The difference between a sanding sealer and polyurethane is that a sanding sealer is a base coat finish that seals the pores of the wood and provides a smooth surface for applying further finishes while polyurethane is a top coat that provides a durable and long-lasting finish.
We tested sanding sealer and polyurethane on wood using different criteria to come up with this simple guide to help you choose.
| Feature | Sanding Sealer | Polyurethane |
|---|---|---|
| Surface finish | Smooth and clear finish | Warm and tough finish |
| Durability | Comparatively less durable | Excellent durability |
| Number of Coats | Requires less coats | Requires at least 2-3 coats |
| Drying time | 30 minutes to 1 hour | 2 hours to 24 hours |
| Flexibility | Less flexible to changing temperature and moisture conditions | Can adapt to changing temperature and moisture conditions |
| Moisture resistance | Good | Excellent |
| Applications | Used as a base coat for wood | Used as a top coat for wood, metal, concrete, etc. |
Both sanding sealer and polyurethane can make wood look shiny and smooth. But they are different in some ways.
Sanding sealer is good for the first coat. It makes the wood less rough and more even. It also stops the wood from soaking up too much of the final coat.
Polyurethane is good for the last coat. It can also be used for the first coat if you mix it with something thinner. It makes the wood strong and protects it from damage.
The best one to use depends on what kind of wood you have and what you want it to look like.
For s softwood like pine, sanding sealer is better for the first coat. It fills in the holes and makes the surface smooth.
For hardwoods like oak, polyurethane is better for the last coat. It lasts longer and can handle more use.
Some people like how oil-based polyurethane makes the wood look warmer. Others like how water-based polyurethane keeps the wood’s original color.
Sanding sealer can also change the color of the wood a little bit. It makes it darker.
Verdict: There is no clear winner. It depends on your preference and purpose.
Polyurethane is very hard and tough. It covers the wood with a strong layer that can handle a lot of use and damage. It is one of the best wood sealers you can find.
Sanding sealer is not as strong as polyurethane, but it still protects the wood.
It is good for things that do not get used a lot, like walls or ceilings. It can also help other sealers stick better to the wood.
Verdict: Polyurethane is the winner in terms of durability.
Sanding sealer and polyurethane need different numbers of coats to work well.
Sanding sealer is used as the first coat, and then another sealer is used as the last coat.
The sanding sealer makes the wood smoother and helps the last coat stick better. This means you need less of the last coat to make the wood look good.
Polyurethane is used by itself, without another sealer. You can put it on bare wood or on top of another finish.
This can save you some time and work. But you may need more coats of polyurethane to make the wood strong and shiny.
The number of coats depends on the type of polyurethane you use.
Verdict: Sanding sealer is the winner as it only needs fewer coats.
Sanding sealer and polyurethane dry at different speeds.
Sanding sealer dries faster than polyurethane because it is made of different things. It has lacquer and zinc, while polyurethane has resins, plasticizers, and solvents.
Sanding sealer dries very fast, and you can put another coat on top of it in a few hours.
You can also sand it and put another coat of sanding sealer in less than an hour, depending on what the label says.
Polyurethane dries much slower, sometimes more than a day, for some oil-based polyurethane.
You have to wait for the first coat to dry completely before putting on the next coat. This can make the finishing process take longer.
Verdict: Sanding sealer is the winner due to its quick drying time
Flexibility is how well the finish can handle the wood changing size because of heat, cold, or moisture.
A flexible finish can change with the wood, while a rigid finish may break or come off.
Sanding sealer is usually more rigid than polyurethane. This is because the sanding sealer goes into the wood and makes it hard.
Polyurethane goes on top of the wood and makes a flexible layer that can handle different heat and moisture levels.
But this doesn’t mean that the sanding sealer is bad for flexible projects.
It can still make the wood last longer and handle some heat and moisture changes.
But polyurethane is better for projects that need a lot of flexibility.
Verdict: Polyurethane is more flexible than sanding sealer.
Moisture resistance is how well the finish can handle water or dampness.
Polyurethane is usually better than sanding sealer for this.
This is because polyurethane is a kind of plastic that makes a hard, waterproof layer when it dries. It can stop water from damaging the wood.
Sanding sealer is not as good as polyurethane for stopping water.
Sanding sealer can help to protect the wood from some moisture, but it is not made to be waterproof or very moisture-resistant.
This means that it may not work well in places that get wet or damp often, like bathrooms or kitchens.
Verdict: Polyurethane is better than sanding sealer for moisture resistance.
Applications are the different ways you can use the finish. Sanding sealer and polyurethane are good for different things.
Sanding sealer is good for wood projects that need a smooth and even finish.
You can use it on bare wood or on top of a wood stain or dye.
Sanding sealer can also fill in small holes and cracks in the wood, which makes it smoother.
Another good thing about sanding sealer is that you can sand it easily, which is helpful for projects that need more than one coat.
Polyurethane is good for many kinds of surfaces, not just wood. You can use it on metal and concrete too.
It also comes in different types, like oil-based, water-based, and solvent-based, which are good for different things.
Polyurethane is good for projects that need a strong and protective finish, like floors, furniture, and cabinets.
It can also handle chemicals, scratches, and wear and tear, which makes it good for busy areas.
Verdict: Polyurethane wins in terms of applications because it can do more things and work on more surfaces.
Sanding sealer and polyurethane are both good finishes, but they are different in some ways.
The best one for you depends on what you like and what you need.
If you want a finish that makes the wood look clear and natural, then sanding sealer may be good for you.
But if you want a finish that makes the wood stronger and safer, then polyurethane will be a better option.
The best thing to do is to learn more about both finishes, think about what matters most to you, and try both finishes before you choose one.
Both sanding sealer and polyurethane are easy to apply with a brush, spray gun, or rag. However, sanding sealer dries faster and requires fewer coats than polyurethane, making it a quicker and more convenient option for some projects.
Yes, sanding sealer and polyurethane can be used together. Sanding sealer is often used as a base coat to seal the wood and create a smooth surface before applying polyurethane. However, it’s important to make sure that the sanding sealer and polyurethane are compatible and apply them according to the manufacturer’s instructions.
Sanding sealer and polyurethane are generally safe to use when applied according to the manufacturer’s instructions. However, they contain chemicals that can be harmful if inhaled or ingested. It’s important to wear protective gear such as a respirator, gloves, and eye protection when working with these products and to use them in a well-ventilated area.
