Paint primer hides imperfections and provides a smooth base coat for the paint to stick to. But, does primer need to be perfectly even?
Paint primer doesn’t need to be perfect, but it needs to seal every blotch, stain, crack hole, or dent in the material to make the finish smooth. Also, the primer shouldn’t be streaky, as it can affect the finish quality.
Depending on your needs, the primer coating can be rough or smooth. A rough primer coating helps paint stick better. But, if you are using oil-based paint (or paints that stick well), then having a smooth primer works too.
Even Primer Coating
Paint primer doesn’t need to even, except if you apply a transparent (clear) coat over it. Clear coats, such as polyurethane, will reveal the texture of the undercoat. And, if the undercoat isn’t even, the finish won’t appear smooth.
However, the primer doesn’t need to be even when applying a paint coating over it. That’s because you will apply multiple coats of thick paint, covering the primer coating. So, even if the base coat isn’t even, the paint will cover it.
But, if you apply only one coat of paint, the base coat must be even. That’s because one coat of paint isn’t enough to cover or fill the base coat. The finish will look deformed if you apply only one coat of paint over an uneven base coat.
While primer doesn’t need to be perfectly even, it also shouldn’t be deformed. If the basecoat is too deformed, the finish will look deformed too, unless you apply multiple coats of paint.
If the primer coating is super rough, the finish can come out rough. This happens when the primer is applied wrongly with a roller. Paint rollers tend to leave irregular lines and patterns on the finish.
Note: Regardless if the primer is even or out, the paint will stick over it. An uneven base coat will only affect the finish quality (smoothness).
Paint primer isn’t supposed to look streaky. While primer doesn’t have to completely cover the old paint, the old paint also shouldn’t bleed-through the primer. The color shade and quality of the finish will be affected if the old paint is bleeding-through the primer.
If you paint over a dark color, you must apply two coats of primer to properly cover the paint. If you don’t, the dark paint can bleed-through the finish and give it a dark stain.
To prevent a streaky look, use a high-quality primer and roller while applying it. Apply an even coating and more coatings than necessary. Optionally, sand between coats with fine-grit sandpaper to remove the old paint stain from the primer.
The first coat of primer must cover every inch of the surface where the paint will be applied. The coating doesn’t need to be smooth or fine, it just needs to properly cover the entire surface.
The first coat of primer must cover imperfections and seal cracks and holes in the surface. But, it doesn’t have to cover the old paint completely, the second coat must do that. That’s why applying at least two coats of primer when covering old paint is recommended.
Also, the first coat of primer shouldn’t be blotchy, streaky, or drippy. The surface of the base coat must be textured and dry so the next coating of paint (or primer) sticks to it.
Painting over Uneven Primer
You can use over uneven primer coating if you are using self-leveling paint or thick coats. Self-leveling paints are designed to produce a smooth (and even) finish, regardless of how the coating is applied. Also, thick paint will fill and seal the uneven primer coating.
You shouldn’t paint over uneven primer with light (or thin) paint. That’s because thin paint won’t cover the base coat properly and will allow imperfections to show once the finish dries.
Also, light paints tend to produce bubbles or paint pimples if used over uneven surfaces. The light paint is prone to tearing up if exposed to an uneven base coat.
Also, if the primer is streaky, you shouldn’t apply light paint over it. That’s because the paint won’t cover the base coat properly, and the old coating will bleed through the finish. To prevent this, use thick coats or multiple coats of light paint.
Here’s how you can make the basecoat even:
- Apply light coats. Heavy coats are more difficult to control and can lead to runs and drips.
- Allow enough dry time before re-coat.
- Apply it with a paintbrush.
- Don’t mix different types of primers.
- Allow the final coat to dry for at least 1 hour before painting.
- If you apply multiple coats, sand between the coats.
Related Read: What Color Of Primer Should You Use?
The primer doesn’t need to be even or perfect, it just needs to properly cover every area of the surface. Paint will stick over the primer whether the coating is even or not. However, make the basecoat as smooth as you can to get a smooth finish. Sanding the basecoat helps you get a smoother finish.
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,