Primer and paint are similar. They both seal, adhere well, and cover imperfections on a surface. So, can you use primers as paint?
You can’t use primers as paint. That’s because primers are designed to adhere to a surface and provide a base coat for the paint to stick to. If a primer coating is exposed to indoor or outdoor elements, the coating will get removed.
A primer doesn’t have protective additives that make its coating resistant to water or durable. Instead, the primer is formulated with extra adhesion additives, making its coating stick better.
Primer vs White Paint
Primer isn’t the same as white paint. Paint is formulated with resins, paint pigments, solvents, and some extra additives (depending on the type).
For instance, high-gloss paints have a high amount of sheen in their formula, creating a glossy finish that repels moisture. In addition, some oil-based paints have protective additives that make the paint resistant to water.
Because of the protective additives, paint can be used as a final coat on indoor surfaces. Also, paint has lots of pigments that beautify and change the appearance of a surface. When dry, paint forms a durable coating that can last for years.
On the other hand, primer is formulated with resins, solvents, additive agents, and no paint pigments (some do) or protective additives. So, its coating isn’t colorful and doesn’t have a durable finish. Because of its high resins, primer sticks over any surface and is designed to provide a base coat for paints. This means a primer shouldn’t be used as a topcoat or left unpainted.
If applied as a topcoat, the primer will get removed or washed off within 2 weeks. That’s because a primer doesn’t have protective additives that make it durable or resistant to elements.
Primer Without Paint
You can use primer without paint temporarily. But, once the primer dries, you must either paint over it or seal it. That’s because it isn’t formulated with protective additives, and the coating will get removed if exposed to water or other elements.
Also, a primer coating is water-soluble so the paint can penetrate it and stick over the surface. This means liquid can also penetrate it, so it won’t protect the surface underneath.
If you apply primer over bare wood and don’t apply paint or sealant over it, the finish will last less than 2 weeks. Also, the finish will look dull because most primers don’t have paint pigments (some do). Primers have more resins on their formula that allow them to stick to any surface.
However, you can use primer without paint if you seal it. A sealant, such as polyurethane, will form a glossy layer that will protect it from moisture, water, or scratches. But, the finish will look dull because polyurethane is a clear coat with a transparent finish.
Paint Without Primer
You can apply paint without a primer, but the surface must be clean and sanded. A primer coating provides a smooth coating that helps the paint stick better. But, if the surface is already clean and smooth, then a primer isn’t needed.
Also, sanding will remove imperfections and create tiny ridges into which the paint can penetrate. This helps the paint to stick better and create a smooth layer.
However, for non-porous and slick surfaces, a primer is needed before paint. That’s because paint can’t stick over non-porous surfaces (such as glass) because it can’t penetrate its surface. But, since primer has extra resins, it will stick over a slick or non-porous surface, and you can apply paint over it.
Also, if the surface is wet, damaged, or stained, you need a stain-blocking primer. A stain-blocking primer will create a base coat over the surface and prevent stains or moisture from penetrating its coating and reaching the paint (from underneath). This is helpful if you are painting over a stained surface and want to avoid bleed-through.
Also, if you want to change the color shade of a finish, you must apply a primer. For instance, if you want to change from a dark-colored finish to light colored finish, you need a stain-blocking primer to prevent paint bleed-through.
Related Read: Does Primer Have to Be Even?
You can’t use primer as paint. That’s because they have different formulas. A primer will bond to any material but won’t protect it from anything; also, its coating isn’t durable and will get washed off if left unpainted or unsealed.
Tony is a professional painter and an author of DIY Geeks. Tony has completed over 1,000 painting projects for his clients. It's safe to say he knows what he Is talking about,