All new surfaces and most of the repaired surfaces require priming before the topcoat is applied. A primer's main functions are to limit absorption of paint into the surface (seal) and to provide good adhesion (bond).
What are some of the functions that a primer performs?
Is there one single primer that will work in all applications?
Not really, that's why there are so many primers on the market. Many manufacturers do offer a "universal" primer/sealer/stain-killer with broad performance capabilities. However, the performance properties may not always satisfy the task at hand. To help with choosing the appropriate primer, certain factors must be considered.
Listed below are some factors to consider when selecting the most appropriate primer.
Repaint: Primer is usually not needed unless paint is very chalky, bare wood is exposed, or if repairs have been made to the surface with spackle, wood filler, putty, etc.
New Wood: Prime with quality acrylic latex or oil primer; use stain-resistant primer for cedar, redwood, mahogany or other "staining woods"; oil-based primers are better for severely staining woods.
Weathered Wood: Thoroughly sand weathered or exposed wood; dust off the surface; then apply a quality latex or oil primer before applying paint.
Masonry: Prime with a masonry sealer on new or unpainted masonry.
Ferrous Metal: Prime with a rust-inhibitive high-quality acrylic or oil-based primer. Note: While most rust inhibitive primers are alkyd/oil-based, some latex products have been formulated with rust inhibitive properties. If using a latex primer, check the label to make sure it’s recommended for ferrous metal.
Aluminum Galvanized Metal: Prime with a high-quality acrylic primer. Note: Galvanized metal is coated with zinc, which is incompatible with alkyd/oil products.
Hard to coat/Non-porous surfaces: Prime with a high-quality acrylic bonding primer. Bonding primers offer unparalleled adhesion to some of the most challenging substrates such as: Glazed brick/block, PVC, most plastics, Formica, glass/fiberglass. These types of substrates propose a challenge due to being mostly non-porous and having almost no surface profile and should be properly deglossed.
Ceramic Tile/Glazed Block:
Concrete Block/Rough or Pitted Masonry:
Cured Concrete/Fiber Cement Board/ Pre-Cast Concrete:
Ferrous Metal (Iron/Steel):
Sheet Panelling/Wall Board:
Sealing Wallpaper Adhesive:
Knots in Wood:
In conclusion, please remember that the purposes of priming include sealing the substrate from stain bleed-through, providing a uniform surface for topcoat, and to help assure a tight bond between the paint and the surface to be painted. Proper surface preparation and applying the correct primer is necessary to ensure a proper paint foundation prior applying the topcoat. If you have any questions, please call your local Regal Paint Centers store.