Primers are very similar to paints. They seal, adhere well, and when dry, form a smooth finish. No wonder you want to use the primer as paint. But can primer be used as paint? Here is the answer to that.
Primer can be used as paint. Primers can be used as finishing coats on a piece of furniture or material. But, the primer coating needs to be sealed after to give it color and improved durability against the elements.
This is because primer coatings can’t withstand heavy use or the elements. So, if the primer is used as paint and left unsealed, it will break down and flake off.
But there is more to know about using primer as paint and this post digs right into the topic. Let’s go deeper.
Can You Use Primer Without Paint?
You can use primer without applying paint over it as long as you seal the primer after. But it’s not advised to use primer without paint. This is because primers are designed to be used as base coats and if used without paint, the finish will turn flaky.
Paint primers are a bit different from regular paint. Primers are designed with additives and resins that make the primer coating adhere to any type of surface.
The resins in the primer when dry form a strong and smooth surface that allows the paint to stick to it. This is why it’s usually advised to prime before painting for good paint bonding.
Paint on the other hand is designed with paint pigments. When the paint dries, the pigments present help the paint to withstand the elements.
If you prime without painting over it, you’ll still get a smooth finish with the primer. But the finish will be prone to the elements since paint primers have resins (that improve bonding) but not pigments (that improve durability).
The finish will also be dull because primers when dry give a white or grey finish. So the finish you get from priming without using paint will not be vibrant.
Your best bet is to paint over the primer but this doesn’t mean you need to use regular paint. If you like the finish of the primer that much, you can apply a clear coat to seal it.
The clear coat when dry will form a thick film that will give the primer finish increased durability and to get color, you can use a clear coat that is tinted.
The best clear coat to use over primer finish is an acrylic clear coat. Acrylic clear coat is both durable and colorful.
Can You Use Paint Without Primer?
You can use paint on a material without priming first as long as the material is properly sanded.
The main purpose of priming before painting is to improve paint adhesion and to seal the material to be painted. Sanding also does both of these tasks though not as good as a primer.
When you sand, you create tiny dust particles that are used to fill and seal the material to be painted. Also, the grits in the sandpaper leave tiny marks on the material that the paint can bite into to improve paint adhesion.
As an added advantage, sanding also helps to remove imperfections and gloss that can prevent good paint bonding.
So as long as you sand first, you can paint without priming. But using a primer will improve the finish.
Tip: To get the best finish, sand and prime the material to be painted before applying the paint.
Is It OK To Leave Primer Unpainted?
It’s not ok to leave primer unpainted because the primer will degrade and turn chalky or flake off if paint or clear coat isn’t used over it. This is because primers don’t have paint pigments and as such the finish will be severely affected by the elements and friction.
Primers as explained earlier don’t have paint pigments. Instead, they have a large volume of resins. Resins are chemical compounds that react to hold paint pigments together. The resins present in the primer allow the paint used on the primer coating to bond well to surfaces it would otherwise not stick to.
While the resins improve paint bonding, they don’t improve paint durability. What makes paint moisture resistant and durable is the sheen of the paint after it dries. This sheen is made when the solvent is evaporated from the paint pigments. The pigments harden to form a colorful sheen that prevents moisture and friction from damaging the finish.
Paint primers don’t have this sheen because they usually don’t have pigments. So when you paint over primer, the paint will give the primer sheen (durability) while the primer will give the paint resins (adhesion).
If the primer is left unpainted, all the primer coating gets is adhesion and no durability or color. This will allow the elements to affect the primer coating.
But since the primer coating is well bonded, it will not come off when affected by the elements. Instead, the coating will gradually decrease and turn chalky or powdery. This will make the finish ugly.
How Long Can You Leave Primer Unpainted?
You can leave the primer unpainted between 24 hours and 30 days. On average, you can leave primer coating unpainted for 2 weeks before you will need to re-prime.
It’s important to note that temperature variations, dust, and moisture can reduce the amount of time you can leave a primer coating unpainted.
Tip: To know how long you can leave your primer coating unpainted, check the primer can for instructions on how long you have before you’ll need to re-prime.
You might have applied the primer coating before you realized that the paint you intend to use has gone bad or wouldn’t be enough. There is no need to panic. You still have time to get everything you need by leaving the primer coating unpainted. But this time is usually limited by humidity and temperature variations.
Water-based primer coatings tend to last longer if left unpainted due to the low levels of chemicals and absence of oils in the primer’s make-up. You can leave water-based primer coating unpainted for over 3 weeks before you need to re-prime.
Oil-based primer coatings on the other hand don’t last very long if left unpainted. This is because oil-based primers are formulated with synthetic and natural oils that don’t react well to temperature variations or moisture.
For instance, most oil-based primers are formulated with linseed oil. When linseed oil is exposed to heat, polymerization occurs. Polymerization is a process in which the tiny molecules in the linseed oil start to combine chemically. This will cause the linseed oil to become thicker due to internal friction (or polymerization) caused by heat exposure.
The continuous exposure to heat will increase the viscosity of the entire primer coating. This means the oil-based primer coating will become semi-solid or thicker and this usually means, you’ll need to re-prime.
Related Read: How Long Does Primer Last?
Is Primer The Same As White Paint?
Primer isn’t the same as white paint. Though primer when dry produces a white finish that is similar to the appearance of white paint, both products are different.
The white appearance produced by primer is more of an off-white or grey color. White paint on the other produces a pure white finish. Asides from the slight color variations, the features of the finish also tell both products apart.
Primers when dry have no paint pigment which means the finish is chalky or flaky. If you rub your hand on dried primer coating, it will feel slightly dusty. It’s not dust you feel at your fingertips but paint particles because the primer finish isn’t sealed and it has no sheen.
The primer coating is designed to feel this way because the coating has to be textured (or slightly rough) to allow paint coatings to adhere to it well.
On the other hand, the finish gotten with white paint feels different. Regular latex white paint for instance doesn’t appear flaky. When white latex paint cures, the finish will feel dry but you wouldn’t feel any grain or paint particles.
Oil-based white pains can’t even be compared to primer paints. This is because oil paints when dry form a glossy finish. Primer as explained earlier though white wouldn’t appear glossy unless the primer was sealed with gloss.
Does this mean you can’t use primer as white paint? Not quite.
Though primer is different from white paint, it can be a good substitute. For paint jobs where you just need a whitish appearance or where you have run out of regular white paint, you can use a primer. But use a sealant on the primer
Tip: If you are using a primer as white paint, ensure to apply a clear coat on the primer to seal it.
Can Primer Be Used as The Finish Coat When Painting?
Technically, yes. Primer can be used as the finish coat when painting but the primer coating has to be sealed with a clear coat. If left unsealed, the primer coating will flake off.
This is because primers aren’t designed to be used as the final coat but the first coat. So if you don’t seal the primer finish or paint over it, it will come off.
Let’s face it. The finish gotten from primers is good enough to be used as the final coat of a paint job. But this is in appearance only. As explained earlier, primers can’t withstand the elements. So if you are using a primer as the finish coat, you’ll need to seal the primer coating with a clear coat.
This then begs the question, is primer indeed the final coat since you are still going to seal it with a clear coat?
Well, primer is still the finish coat even after it is sealed. The clear coat added to seal the primer finish is called the sealant.
So if you were to call the primer the finish coat, you would be right and someone calls the sealant the finish coat, he or she is also right. It’s just semantics, really.
The most important thing is to never leave the primer as the last coat.
Overall, you can use paint primer as paint. The primer coating will bond well to any material, so paint adhesion isn’t going to be a problem.
However, you will need to seal the primer coating or apply another paint over it. If not, the primer coating will turn chalky.