How to Choose and Use Primer

One of the most powerful tools in any pro painter’s arsenal is what goes underneath the paint — primer. Primer is an excellent problem-solver that’s less like paint and more like glue. It sticks to whatever you’re prepping and turns it into a smooth, uniform surface that’s ready for paint.

But if you’ve ever walked down the primer aisle at a home center, you know the primer choices are mind-boggling. To cut through the clutter, we asked three professional painters, each with 20-plus years of experience, to give us their recommendations for the best primers to use for common painting challenges. Their experience will help you choose the best primer for the job, so your paint will look better and last longer.

Problem 1: Interior stains and odors

Some stains will bleed right through most primers and paints no matter how many coats you apply. The same goes for severe odors like smoke from fires and cigarettes. The solution is stain-blocking primer, which is available in oil-based (alkyd) and water-based (acrylic-latex) versions.

• Oil-based versions give off a nasty smell and require paint thinner for cleanup, but they’re more reliable for blocking water-based odors and stains like rust, nicotine, smoke, wood tannins and, of course, water (see “Shellac: The Original Primer,” below, for dealing with severe stains and odors).
• Water-based stain-blocking primers offer easy cleanup and less odor and come in low- and no-VOC (volatile organic compounds) formulations. These work best to block solvent-based stains like crayon, grease, ink and scuff marks.
• Both versions are white, so it’s a good idea to tint them gray or close to your topcoat color if they’ll be covered by dark-colored stain block paint.

Do I Always Need to Prime Before Painting?

You don’t have to prime previously painted surfaces if the paint is in good shape—no chipping or peeling. Interior walls usually don’t need priming except in the case of stains, repairs or a paint color that’s drastically different. Interior painted woodwork usually needs spot priming with wood primer at a minimum. Exterior paint takes such a beating that it almost always needs priming with an exterior paint primer.

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