When to Use a Primer and What Could Happen if You Don´t

When to Use a Primer and What Could Happen if You Don´t by Valentin | Last Updated: May 6, 2021
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Using a Primer is very important for a lot of projects but not for every single one. While it is advisable to use a primer it is not always necessary to prime every surface before painting it. But for beginners, it is sometimes hard to understand when and why to use a primer in the first place. So I decided to write this article to help you understand what a primer does exactly and when to use one.

As a general rule, a primer is needed when the surface is either too rough, too uneven, not sealed yet, or when it is a surface that the chosen paint won´t adhere to properly. If no primer is used the paint might peel off, bubble up, or the final paint job might have slight discolorations.

As I said, you don´t always need a primer but knowing when to use one and when you don´t need one is key here. Otherwise, you might end up with a poor paint job. If you want to be safe then using a primer every time is probably the safest bet but it is also more work and it can get quite expensive.

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Applying Paint Without Using a Primer

A Primer is needed to prepare the surface for the paint application. Priming a surface will create the perfect conditions for the paint. It will also create a strong bond with the underlying surface to ensure that the paint won´t peel off or bubble up after a while. But do you really need to use a Primer every time you want to paint something?

As a whole, paint can be applied without using a primer but only if the surface is smooth enough or if it has already been sealed, or if the paint naturally adheres to the surface. Untreated Wood or already painted Walls, for example, will accept paints without the use of a Primer.

There are a few things that you need to be aware though if you plan on painting a surface without using a primer first.

You will generally need more coats of paint in order to get good coverage if you don´t use a primer first.

If you paint on untreated wood, for example, then the grain of the wood might be visible after you are done painting it. This can be a great effect for some specific projects but it might also be not desirable. So keep that in mind.

A Primer also ensures that the paint adheres properly to the surface. That’s why it is usually used for surfaces that the paint would not adhere to properly on its own.

So if you want to paint treated wood, sealed wood, bare Drywall, or a similar surface then you have to use a primer to ensure that the finished paint job adheres properly to the material and to avoid any discoloration later on.

If you don´t know how a surface has ben sealed or what kind of paint was previously used on that surface then your safest bet is to simply use a strong adhering Primer before painting it.

You can follow this link to read my article about painting already painted wood, where I explain how to properly apply a primer and where I share my personal favorite Primer that will basically adhere to anything, even glass and ceramic.

Painting Walls Without the Use of a Primer

When it comes to painting wall then choosing to use a primer or not really comes down to a few different things.

As a general rule, a primer is necessary for painting walls when the previous paint job is darker than the new paint or if the old paint job is very different, color-wise, from the new paint’s color. But if the new paint is very similar to the previous color of the wall then no primer is necessary.

I almost never use a Primer when I paint over a white wall.

But on the other hand, I almost always apply a primer first when the wall, that I want to paint, is colored. Mainly because no matter what kind of paint you paint over it the color will shine through until you applied multiple coats.

So to save time and paint it is simply easier to apply a coat of primer before painting the wall with the new paint.

It is also important to mention that you have to apply a primer to bare Drywall that hasn´t been sealed yet. Because no matter how much paint you add to a bare Drywall you will always see every imperfection through and the finished paint job will almost always discoloration issues.

Using Simple White Paint as Primer

A Primer is basically nothing more than a special, very thick paint that adheres well to multiple surfaces while creating a perfect surface for a lot of different paints. So can´t you just use simple white paint as a primer instead of buying a real primer that is much more expensive?

Flat white paint can´t be used as a primer because it won´t adhere properly to most surfaces that primers can adhere to. A Primer looks like regular white paint but it will adhere to, smooth, cover most surfaces much better than white paint while also preparing the surface for further paint applications.

There are a couple of things that primers can do that simple white paint just can´t but the most important thing is adhering to surfaces and preparing them for a future paint application.

You might be asking yourself, but why don´t we just color primers and suddenly we have a type of “paint” that adheres to everything.

Well, there are 2 in 1 primer and paints that do exactly that but while they are awesome for a lot of different projects they aren´t really the solution or the reason to get rid of primers.

There can be a real benefit of using a simple primer before painting the surface with a dedicated paint.

For one, the finish will be smoother and more brilliant, depending on the paint of course.

Simple paint is, most of the time, cheaper than a 2 in 1 primer and paint in one. So if you want to paint something in multiple colors, for example, then priming the surface with a regular primer and painting the primed surface afterward is actually easier and much cheaper.

Hi, I am a passionate maker and professional prop maker for the entertainment industry. I use my woodworking, programming, electronics, and illustration know-how to create these interactive props. And I share my knowledge and my experience on this blog with you so that you can become a maker yourself.