How to Use Chalk Paint as a Primer
Although there are many, many online resources that instruct how to make chalk paint, the simplest way is simply adding a slurry of pure calcium carbonate to latex paint. The prepared chalk paint can be applied directly to bare or sanded wood. When fully dry, this paint is easily sanded with fine sandpaper to be topcoated. For interior wood and related porous surfaces, chalk paint is an effective primer.
Many modern paints are sold as primer/paint in one coating for frugal shoppers who want to minimize time on home DIY projects. The problem is that these all-for-one paints usually require multiple coats and adhesion might be compromised. Instead, a single can of paint be used for priming and painting separately. By adding chalk, a superior primer is created, and the remaining paint can be tinted or mixed with another color of paint for the topcoat.
Chalk Paint Recipe
The following is provided just as a starting point. You may need to adjust the formula to suit your needs. This recipe is based on flat or matte latex paint. If you have semigloss or gloss, then your chalk amounts will be higher.
- 1/2 quart of flat or matte latex paint
- 3 tablespoons of calcium carbonate
- 4 tablespoons of warm tap water
I normally recommend distilled water for crafts and painting, but when mixing chalk with water, we are adding what is already there. It is important to make a slurry of the chalk before adding to the paint to limit any lumps of chalk of forming in the paint.
Prepare Chalk Slurry
Put the chalk into a separate container, and add warm tap water until a smooth slurry is obtained through mixing. It should be like a heavy whipping cream consistency. This is basically a dispersion of sorts, and you add this to your latex paint. You’ll notice that even though you have added water to the, mix the new paint is actually thicker. DO NOT THIN! The viscosity helps keep everything suspended. Periodically stirring while applying coats is required.
Calcium Carbonate Slurry
Apply First Coat
It is recommended that the first coat goes on thin for fast drying. Complete coverage is not needed and is not recommended. This first coat establishes adhesion and provides a tooth or key for any following coats. The paint itself, having a significant amount of minerals, will set up and dry VERY quickly. DO NOT LEAVE PAINT ON BRUSH! Rinse brush thoroughly after each coat. Otherwise, when you return in 30 minutes to apply a second coat, you’ll have a stiff brush to deal with. The bright side is that you’ll be able to apply three coats in a couple hours total.
Variations in Chalk Content in Recipe
Type of Paint
Amount of Chalk Per Qt. of Paint
Water Added Per Qt. of Paint
Flat latex paint
Semi gloss latex paint
Gloss latex paint
Additional Coats of Chalk Paint
After letting the first thin coat of chalk paint dry, it is now time to apply a second coat. Just like the oil painting adage of “fat over lean," the second coat can be a bit more liberal. Not only will this coat come real close to 100% coverage, but small scratches and pinholes can be at least partially filled. This is because the chalk is acting like a putty. This chalk paint is a high-solids sandable primer after all.
If the topcoat is going to be a dark color, you can stop here and let the chalk paint fully cure for 24 hours before topcoat. On the other hand, if you really want to fill scratches and pinholes better or want to try to hide a dark color under a lighter one, a third coat will be necessary .
Prepping for Top Coat
After 24 hours have passed and all coats of chalk paint are thoroughly dry, it can be prepped for the topcoat. The chalk in the chalk paint allows it to be easily smoothed with fine sandpaper. Once sanded to a perfectly smooth finish, the only thing needed is a thorough wiping down with a damp towel to clear paint dust before painting.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.