Water-based finishes, such as chalk paint, are sealed to reinforce and protect them from scratch marks and water damage. So, how to seal chalk paint?
To seal chalk paint, sand the finish with fine-grit sandpaper and apply 3 coats of the chosen sealant over it. The top choices are polyurethane, wax, or varnish.
The sealer will alter the appearance of the finish. So, it’s best to use a sealer made for chalk paint.
Does Chalk Paint Need A Sealer?
Applying a sealer over chalk paint isn’t mandatory, but it’s recommended. The sealer makes the finish more durable and resistant to moisture, dents, and other factors that can ruin it.
Chalk is a water-based paint that doesn’t have a glossy topcoat, so it isn’t durable. In addition, the absence of a glossy top coat makes it prone to early chipping and damage. Especially if the finish is exposed to heavy use, contact friction, or daily wear and tear.
A sealer will protect the chalk paint from damage. However, protection isn’t the only reason for sealing it. Here are some more reasons:
- Gives a Reflective Finish – Chalk paint, when dry, is dull, but applying a sealant over the finish can make it glossy.
- Protect It From Stains – Coffee, water rings, dust, and grime can affect the finish. But, a sealant prevents this from happening.
- Makes Chalk Paint Waterproof – Chalk paint is prone to water damage, especially outdoors. Sealing it will protects it from water damage.
- Weather protection – If the paint is used outdoors, an exterior sealer coat will prevent discoloration from UV rays and mold growth.
- Saves time – Instead of touching up an unsealed finish, the sealer protects it so it will last longer. This means you don’t have to touch it up so often.
Dry Time Before Sealing
The chalk paint coating must fully cure before sealing; this takes between 1-7 days. This gives the solvent (water) enough time to evaporate, and the particles enough time to harden and become compact enough.
If you seal too soon, you will ruin the finish. That’s because all sealants are water-resistant, so if the solvent hasn’t still evaporated from the coating, it will get trapped between the paint and sealant coating. The solvent won’t allow any of the finishes to dry; this creates a sticky finish.
You also must sand the finish before sealing it. So, if the chalk paint isn’t dry, the sandpaper will get clogged by the wet paint residue making the entire finish messy. This will ruin the finish. That’s why it’s recommended to wait until the coating has fully dried (cured) before sealing.
How To Seal Chalk Paint?
It’s easy to seal chalk paint, but for best results, you need the right sealer. You can use different types of sealers, but each sealer gives different results and has a different application method.
So, to make this guide even more helpful, we have compiled a list of the top 5 sealers that can be used on chalk paint. Including the pros and cons of each choice to make your decision easier. These are:
- Chalk Lacquer
- Wood Glaze
Let’s examine these sealers one after the other.
1. Use Wax
The most common sealer for chalk paint is wax. This is because both have a similar rustic appearance. You can apply it by rubbing it with a lint-free cloth or using a wax brush repeatedly until you are satisfied with the finish.
However, wax is thick and will deepen the color of the finish (once it dries). It takes wax 2 weeks to cure over chalk paint. This means you can’t use the furniture for 2 weeks. Once the wax cures, it forms a tough layer that protects the finish from scratches, dents, and moisture.
Chalk paint must dry for 24 hours before applying wax.
Here’s a how to do it:
- Sand chalk paint with fine-grit sandpaper.
- Remove dust using a dust cloth or vacuum.
- Prep the wax sealer in an open container.
- Wipe the wax over the finish using a lint-free cloth. Work in sections and cover every area of the surface.
- Leave the first coat to dry for about an hour and then apply the next coating.
- Wipe off excess wax with a cloth.
- Leave the wax to dry for 24 hours before polishing or buffing.
- Leave the finish to cure for about 2 weeks before subjecting it to regular use.
- It compliments the rustic appearance of chalk paint.
- It deepens its color.
- Hides imperfections and blemishes on the surface.
- It is water-resistant.
- Slow dry time.
- You need to occasionally touch up and re-apply it because it doesn’t last very long.
2. Use Lacquer Sealer
Unlike wax which deepens the finish color, lacquer is a clear sealant that highlights the color and texture of the finish. It also offers more protection than wax does. That’s because it has resins and additives that protect the surface underneath from marks and chipping.
Lacquer also dries fast and can be applied with a bristled paintbrush.
Here’s how to apply it:
- Sand finish with fine sandpaper.
- Remove dust and wipe the surface.
- The finish should be smooth because the lacquer won’t hide any spots or blemishes.
- Stir the lacquer using a paint mixer until you have an even consistency.
- Apply lacquer using a bristled brush and wait for 2 hours to dry.
- After 2 hours, buff the first coat with 400-grit sandpaper and apply a second coat.
- Wait 24 hours for the lacquer to cure.
- Dries fast (15 minutes at room temperature).
- Last for years before there is any sign of damage.
- Lacquer is water-resistant.
- You can use it from the container.
- It is formulated with UV blockers.
- Moisture and contaminants can affect and ruin a lacquer finish.
- Lacquer can develop bubbles, fish-eye, and orange discoloration if it isn’t applied correctly.
3. Use Polyurethane
Polyurethane is a sealer made by mixing different sealers, additives, resins, and solvents. If applied over chalk paint, it will form a thick, glossy, and durable top coat.
There are two types of polyurethane; water-based and oil-based. Water-based polyurethane is used over water-based paints, such as chalk paint. It dries fast, is easy to apply, and requires only 2 coats to cover a surface.
On the other hand, oil-based polyurethane is used over oil-based paints, such as enamel. The oil-based polyurethane tends to turn yellow and can affect the color shade of the finish.
For outdoor items, you must use exterior polyurethane as it protects the surface more than water-based poly.
Here’s how to apply polyurethane over chalk paint:
- Sand the finish with fine sandpaper.
- Remove dust using a vacuum.
- Depending on the type of polyurethane, you’ll be required to shake or stir the polyurethane.
- Apply the first coat of polyurethane by using any appropriate applicator method.
- Wait for the first coat to dry and then buff it with 400-grit sandpaper.
- Apply the second coat for added durability.
- Leave the polyurethane to cure.
- It is easy to apply and can be applied with a roller, spray gun, or paintbrush.
- It protects against all types of scratches and dents.
- Water-based polyurethane doesn’t turn yellow.
- Oil-based polyurethane turns yellow after a few months
4. Use Varnish Sealer
Varnish is an oil-based sealer that forms a tough and glossy film over finishes. The tough and glossy finish of varnish protects finishes from moisture and stains and can withstand constant heavy use. It’s recommended to use it over high-traffic areas such as floors, chairs, kitchen cabinets, and tabletops.
Here’s how to apply it:
- Prep the finish.
- Thin the varnish with 10% mineral spirits.
- Apply the first coat of varnish with a bristled paintbrush.
- Leave the varnish to dry for 2-4 hours before recoating. In humid conditions, wait about 12 hours before recoat.
- Leave the finish to dry and cure. This can take up to 72 hours.
- It is tough and durable.
- It makes the chalk paint water-resistant.
- When dry, it provides a glossy finish that can highlight the finish underneath.
- Varnish lasts very long (10-20 years)
- Not all varnishes are suited to outdoor use as it tends to discolor when exposed to direct sunlight
- It is prone to dust build-up and can be difficult to clean without a solvent
5. Wood Glaze Sealer
Wood glaze is easy to apply, and it takes a few coats to archive a smooth finish. To apply it, use a paintbrush. But, you must wipe off the excess, so it doesn’t gunk up the finish.
When dry, wood glaze alters the color of the finish; will either deepen or brighten it, depending on the type of glaze you use. However, wood glaze doesn’t offer good protection like other sealants mentioned here. So, you should use wood glaze for decorative and low-traffic surfaces.
Here’s how to apply it:
- Prep the wood glaze by following the manufacturer’s instructions.
- Wipe and sand the finish.
- Apply two coats of wood glaze.
- Wipe off the excess within an hour after application.
- Touch up with an extra coat of glaze.
- Let the wood glaze dry for 24 hours and buff or polish it with a polishing cloth.
- Easy to apply
- It will complement the appearance of the chalk paint
- It helps to highlight the curves and carvings of the finish.
- This sealer doesn’t offer much protection from scratches and dents.
Things To Know
Can You Leave It Unsealed?
You can leave chalk paint unsealed, but only for decorative and low-traffic objects or areas.
For instance, if you use it on your wall attachment, flower vase, or wall frame, you can leave the chalk paint unsealed because these objects wouldn’t see frequent use or friction. As a result, the finish will last longer and preserve its color shade.
But, you shouldn’t leave the chalk paint unsealed for high-traffic surfaces such as tabletops, chairs, or walkways. Doing so will cause the finish to get ruined from spills, moisture, dents, friction, and dropped items.
Do You Need To Sand Before Sealing?
You don’t have to sand chalk paint before sealing if its finish is still fresh and in good condition. However, if its finish is old or has defects, you must sand it.
Sanding helps to remove imperfections on the surface and even out the finish so the sealer can sit properly. Sanding also improves adhesion between them. To sand chalk paint, use fine-grit sandpaper. Avoid using medium or coarse-grit sandpaper as it will remove the finish.
Top Coats To Avoid
You should avoid water-based topcoats for outdoor surfaces. Water-based sealer doesn’t protect the outdoor surface as good.
In summary, you must seal chalk paint for outdoor surfaces, but you don’t have to seal it for indoor or decorative surfaces. To seal it, use polyurethane, wax, lacquer, varnish, or wood glaze. The paint must fully dry (cure) before sealing it. If you seal too soon, the finish will turn sticky and might peel off.