Chalk paint sticks well to porous surfaces, such as wood. But, can you use it on metal?
You can use chalk paint over metal, but since metal is non-porous, it doesn’t stick well to it. However, you can sand the surface to create tiny scratches that the paint can penetrate or stick into.
Also, if the metal surface is painted or sealed, you must remove the previous finish first. That’s because a sealer will prevent paint from penetrating a surface.
Chalk paint will stick to bare metal as long as its surface is in good condition and you sand it. However, if the metal is painted or stained, chalk paint won’t stick. You must remove the previous coating to allow the paint to stick to it.
Also, chalk paint doesn’t stick well to rusted metal, even if it sticks, it will peel off in a few weeks. So before applying it, you must remove the rust (and prevent it).
The paint must penetrate a surface to stick. But, since metal is non-porous, it doesn’t allow the paint to penetrate its surface. So, you must sand it lightly to create tiny scratches (ridges) for the paint to soak into.
You can also use a stain-blocking primer to increase the bonding between chalk paint and metal. The primer will serve as a base coat for the paint and help it to stick better.
Compared to other paints, chalk paint has good adhesive qualities. Because of its thin and water-based nature, it sticks so well on surfaces that it can be used as a base coat (primer) for other paints or sealers.
Related Read: Will Chalk Paint Adhere To Glass?
Chalk Paint Dry Time on Metal
It takes chalk paint 30 minutes to dry enough for a re-coat and 24 hours to dry fully (cure). For paint to dry its solvent (water) must evaporate from the coating. Since chalk paint uses water as its solvent, the paint dries fast because water evaporates fast.
Also, since metal is non-porous, the evaporation process of the solvent happens faster. That’s because all the paint is over the top layer of the metal, and no paint is soaked into the surface. Since paint hasn’t soaked into the surface, the evaporation rate will happen faster and the paint will dry faster.
However, the dry time of chalk paint depends on the room temperature, humidity levels, thickness and number of coats. During moist temperatures, paint takes longer to dry.
How To Apply Chalk Paint On Metal?
Painting metal with chalk paint is easy; clean, sand, prime the metal, and then apply the paint.
Here are the tools you need:
- Chalk Paint
- 1 x Sealant (Polyurethane or Spar Varnish)
- A Mild Solvent (Like Rubbing Alcohol)
- Wire Brush
- 1 x Primer
- Foam Roller or paint sprayer.
1. Clean The Metal
First, clean the metal surface. Cleaning will remove dust, grease, and grime from the surface that can prevent paint from sticking.
To clean it:
- Mix detergent (or soap) with warm water.
- Damp a clean rag with the mixture.
- Use the dampened rag to clean the metal surface.
- For stubborn stains, use a degreaser.
- Wait 5 minutes.
- Clean the surface with water.
- Allow it to dry.
2. Remove The Existing Finish
If the metal surface is already painted, stained, or sealed, you must remove the existing finish first. A sealer will prevent chalk paint from penetrating and sticking to its surface.
To remove an existing finish:
- Use mineral spirits for oil-based paints or rubbing alcohol for water-based paints.
- Apply the paint remover compound over the painted surface.
- Wait 15-20 minutes.
- Once 20 minutes have passed, the paint will start to bubble and change its form.
- Use a plastic paint scraper to scrape most of the paint.
- Re-apply the paint remover compound to leftover paint.
- Use a rag to remove the paint.
- Remove the paint removing residue from the metal (IMPORTANT!).
- Allow the metal to dry.
- Sand it with ultrafine-grit sandpaper.
You must use a plastic paint scraper as a metal paint scraper can damage the surface. Also, you must remove the paint remover residue from the metal as it can discolor or damage it.
After you remove the paint, sand the surface with ultrafine-grit sandpaper. Sanding will remove any leftover paint and create tiny scratches for the paint to soak into.
3. Apply Primer
After the metal surface is clean and sanded, apply a stain-blocking paint primer. Paint primer has extra additives that allow the coating to stick to a metal surface. The primer will serve as a base coat and offer a smooth and even layer for the paint to stick to.
To apply primer:
- Use a paintbrush, roller, or sprayer.
- You must use a stain-blocking primer as it prevents stains or moisture from affecting the finish.
- Apply 2 coats of primer on the metal.
- Wait until the first coat dries before applying the next one.
Related Read: Does Chalk Paint Need Primer?
4. Apply Chalk Paint
Once the second coat of primer dries, apply the chalk paint.
Here’s a step-by-step guide:
- Use a paintbrush, roller, or sprayer.
- Apply 3 coats of chalk paint to metal.
- Wait until one coat dries before applying the next one.
- Optionally, sand between coats (except for the final one).
- Seal the finish.
5. Seal The Finish
For outdoor metal surfaces, you must seal the chalk paint because it isn’t durable enough to withstand outdoor elements and will get washed off. Also, chalk paint isn’t water-resistant and won’t protect a surface from moisture or scratches.
To seal outdoor it, use exterior polyurethane or spar varnish. When dry, a sealer will produce a glossy clear coat that protects the finish from moisture, water, and scratches. However, you must apply 2-3 coats of sealer for proper coverage and protection.
For indoor or decorative surfaces, sealing is optional. That’s because indoor or decorative surfaces aren’t exposed to elements that can wash or damage the finish.
Types of Metal Y:
Indoor Metal Surfaces
You can paint low-traffic indoor surfaces with chalk paint. That’s because indoor or decorative surfaces aren’t exposed to elements such as water, moisture, or handling that can damage the finish. So, the finish will last 3-5 years on low-traffic indoor surfaces.
For instance, you can apply chalk paint on indoor cabinets because they aren’t exposed to water or moisture, so the finish will last longer.
However, for high-traffic indoor surfaces, you shouldn’t use chalk paint because it will get washed off from the constant touching.
Outdoor Metal Surfaces
You shouldn’t use chalk paint on outdoor metal surfaces. That’s because an outdoor surface is exposed to weather elements, such as rain, that can damage (wash off) the finish.
Chalk isn’t a durable paint because it doesn’t have extra additives that make its finish durable or resistant to anything. If the finish is exposed to constant water, it will get removed.
Chalk paint doesn’t protect metal surfaces from weather elements, it only changes their color. So, if exposed to constant water, the chalk paint will get removed and expose the metal surface to weather elements.
If you want to use chalk paint on outdoor surfaces, seal it with a waterproof sealant. A sealant, such as exterior polyurethane or spar varnish, will protect the finish from weather elements. When dry, polyurethane will form a glossy top coat over the paint and protect it from water, moisture, scratches, and other damage.
You can use chalk paint over a metal surface, but you must sand and prime the surface before painting it. Also, if the metal is already painted, you must remove the finish first.
For outdoor metal surfaces, sealing the chalk paint with a sealant is mandatory as it protects it from moisture, water, and other damage. For indoor decorative surfaces, sealing is optional.
Tony is a professional painter and an author of DIY Geeks. Tony has completed over 1,000 painting projects for his clients. It's safe to say he knows what he Is talking about,