A paint primer has two basic functions: The most fundamental and important function is to attain and maintain adhesion to the substrate. The second primary function is to seal or uniform the substrate. Primers are also expected to contribute to the hiding of a paint system.

By and large, solvent-thinned primer systems are used for solvent-thinned topcoats, and latex primers for latex topcoats. Although this is the general rule, there are exceptions: Oil/alkyd primers are still the most popular universal choice. They may be topcoated with either a latex or oil based finish. Latex primers also may be topcoated with either latex or oil based topcoats.

Why two primers? Both have their own distinct advantages. The oil based primers are much better in checking tannin bleeding on redwood, cedar and other high extractive type woods. Since these tannins are water soluble, latex products have a hard time stopping this bleed in severe cases. Our latex primers are specially formulated with a blend of resins to help check tannin staining.

In areas that are in less than ideal condition (slight chalk, etc.), the oil based primer will perform better than a latex primer. The same is also true in cool weather conditions.

A latex primer will perform better than an oil primer in areas where an internal moisture problem exists. As with all latex, they "breathe" moisture vapor much better than an oil based product. Also, on woods that are dimensionally unstable, such as pine, latex primers take the wood stress much better since they retain their flexibility. Latex primers offer soap and water clean up.

Latex primers are excellent on pre-primed hardboard siding. They do not solubilize the wax in hardboard as may be the case with a solvent based primer. This can result in an early peeling failure with latex topcoats. This happens only on rare occasions.

Oil based and latex primers may be tinted to the approximate shade of the topcoat. Not only does this add to the hide of the primer, it also decreases the contrast of color between the primer and topcoat. Regardless of primer, it is always a good practice to topcoat the primer within a weeks' time for optimum adhesion.

New Wood: Prime with either stain-blocking latex or oil primer. Oil-base primers are better for severe staining woods, such as redwood and red cedar.

Repaint: Primer is usually not required, unless surface preparation is not of a quality nature (very slight chalk, bare wood).

Weathered Wood: Thoroughly sand weathered or exposed wood. Dust off the surface and apply latex or oil primer.

Masonry: Latex primer only. Do not use oil based. If using latex topcoat, topcoat can be used as a self-primer. If old, powdery and eroded, a masonry conditioner should be applied as an initial prep.

Aluminum, Galvanized When painting with latex, surface should be weathered, Non-Ferrous Metals then solvent-cleaned and/or etched. If metal has oxided, apply latex or galvanized metal primer. Avoid alkyd topcoats on galvanized surfaces.