Primers and stain-killing primer-sealers are designed to seal porous surfaces, block out stains, promote adhesion of the topcoat and hide unwanted colors.
Improves adhesion, prevents stains on the surface from bleeding through the finish paint and seals porous surfaces.
Priming the surface also saves paint and prevents paint resins from soaking unevenly into the substrate.
Water-based primer-sealers bind moderately chalky surfaces and offer good adhesion to glossy surfaces and metals. They are almost odorless and clean up with soap and water.
Oil-based primer-sealers can be used on both interior and exterior surfaces. They work well for nicotine stains and cedar bleed. They give off a low odor and clean up with mineral spirits (paint thinner).
Acrylic block fillers should be used to prime concrete block.
Stain-killing primer-sealers are oil-based, water-based or shellac-based. They prime virtually anything that needs painting, including metal, masonry, wood, drywall and previously painted surfaces. They are typically white-pigmented and can be tinted to match the color of the topcoat to reduce the amount of finish paint needed for the job.
Shellac-based primer-sealers are ideal for interior woodwork and spot-priming knots on exterior wood. They are best for sealing off troublesome stains from water leaks, mildew and fire damage. They also seal off odors from smoke and pets. Clean up requires alcohol or a 1:3 solution of household ammonia in water.