Unsealed or porous surfaces absorb the paint too fast for smooth application. Because the paint cannot dry at a normal rate, it does not form a good film. This can rob the paint of its hiding ability, smoothness, and all properties of durability. The correct primer can prevent this from happening.
The primer seals in stains that might otherwise bleed through the top coat . the most common stains are moisture, ink, crayons, sap, etc.
New or rusted bare metal could be a continuous problem unless properly protected with a quality anti-rust primer.
The primer is specifically designed to provide a strong bond to the surface to which it is applied and forms a foundation coat for all paints put over.
The use of a paint as a primer is not recommended. A primer seals the surface and the paint protects it.
The use of either oil over latex or latex over oil is quite satisfactory with today’s paint and primer products. Always follow the label directions on the product you intend to use. Primers are formulated in either oil base or latex base systems and can provide a very satisfactory foundation coat.
Wherever a dirty or greasy surface is encountered before painting, it is recommended that it be washed and rinsed thoroughly. Today’s paints will bond very well to any surfaces that they are applied to.
Paint binds very well to dirt or loose chalk and then if that contaminant falls off the surface, the paint will fall as well.
Cleaning is the most important step to be taken before applying any paint. This is shown every day and proven by the care taken in cleaning the surface on an automobile before it is painted.
Interior and exterior paints are specially formulated each for their specific uses.
Exterior paints are more flexible and would not withstand washing and scrubbing.
- Interior paints are harder and would soon crack and peel if subjected to weathering.