Choose the Right KILZ® Primer for Your SubstrateFebruary 23, 2023
Whether you’re painting inside or outside your home, choosing a primer suitable for the surface is the difference between success and, well, a not-so-great job. That’s why there are several different KILZ® Primers to choose from.
Starting with the right primer could prevent your paint from failing. So, we’ve asked our primer expert, Product Manager John Golamco to answer a few questions about primers and surfaces (substrates) for us.
What to know before starting a paint project
Before beginning any painting project, Golamco says it’s crucial to identify the type of surface you want to prime and paint. Because different substrates accept coatings differently, KILZ formulated with each surface type in mind.
Once you’ve identified the surface type, take note of its condition. Are there any particular circumstances that need addressing before applying a coating? Attend to things like peeling paint, mold or excessive dirt first.
Finally, determine the environmental conditions of the location. Is it damp? Are you painting outside where the surface is exposed to the weather? Or will the paint be subjected to extreme temperature fluctuations? Each of these conditions dictates the primer and paint you choose to use.
Correctly identifying the substrate
Drywall / Gypsum Board
Most interior walls and ceilings are covered in drywall. According to Golamco, the new drywall is very porous and absorbs much paint. So, to avoid applying excessive coats of paint to get the desired color and finish, he recommends using a drywall primer or PVA. The primer will seal the surface before painting so that less paint is required. Since paint typically costs more than a primer, you get a superior finish with less cost. Priming drywall also smooths out the finish and evens out seams, giving better results with fewer coats of paint.
Bare wood is porous and grainy. A primer penetrates the wood fibers, seals the porous surface, and creates a smooth, even surface. Golamco says that applying paint to bare wood without a primer coat produces a dull, blotchy finish. Also, some wood species, like red wood , secrete tannins that could leach through the topcoat paint, impacting its appearance. To avoid this, apply a stain-blocking primer to the bare wood before finishing with the topcoat.
A coat, or two, of primer seals porous surfaces like masonry and concrete, creating a smooth finish for the paint to go on. Without primer, masonry tends to absorb too much paint. And as with drywall, you’ll need to apply more coats to account for the uneven porosity and color. Also, according to Golamco, fresh concrete has a high pH value because its cement binders contain many alkalis. Their presence causes adhesion problems when applying paint and can cause the topcoat color to fade (alkali burnout). But an alkali-resistant primer will better help the paint bond to the masonry and protect the finish over time.
Many people don’t realize that some metals can rust under a paint coating, especially if the metal surface is exposed to moisture. For this reason, it’s essential to prime metal surfaces before painting, particularly when it’s uncoated or bare. Golamco says that metal primers have unique ingredients to make the metal more resistant to rain, humidity, and salt, which cause corrosion.
Since plastics are non-porous, paint doesn’t like to stick to them. As a result, paint on plastic often cracks, blisters, or peels. Golamco recommends first sanding the plastic surface, especially around any edges, curves, and areas with intricate detail to prevent this. Once sanded and cleaned, he says to prime the plastic with a high-adhesion primer. This process will help the topcoat paint adhere the way it should.
The importance of choosing the right primer
Applying primer before painting ensures a beautiful outcome that lasts, but not all primers are created equal. KILZ Primers are engineered and formulated to solve the unique types of challenges presented by different substrates.
“Some multi-purpose primers solve a combination of issues with one product,” said Golamco. “But they’re not formulated to address more severe or complex issues.” If you know the surface type, its condition, issues to be addressed and the environmental factors, then this can help you to choose the right primer for the job. So, if you want to cover a dark color with a light one, paint metal to prevent corrosion, or any other challenging substrate, use a specialty primer for a successful outcome.