Can I Use Self Etching Primer Over Paint? Get Your Answer!

You must be thinking of painting your car all by yourself and might be at sea deciding if you can apply a layer of self-etching primer on your existing paint. Will it be okay to do that?

So, the question is, can I use self-etching primer over paint?

The answer is no. doing such a thing is a huge waste of money because it will scrape away a layer of the paint because of the existing acid in the primer’s formula.

The piece also includes:

• When should you use a self-etching primer?
• What paint to use over self-etching primer?
• How long should you wait before painting over self-etching primer?
• What’s the difference between self-etching primer and regular primer?

Our article covers a wide array of all of these topics. So, let’s dive into the following piece at once. 

Can I Use Self Etching Prime Over Paint?

No, you should not. Using self-etching primer over paint is nothing but a waste of your hard-earned money. 

A self-etching primer is a coating that is applied directly to bare metal. Its formula contains a combination of sulfuric acid and zinc. While introducing the zinc to the metal’s surface, the acid will actually burn or etch into it. This guarantees a strong bond and prevents corrosion.  

So, when you will use self-etching primer over paint, the sulfuric acid in the primer will start a reaction with the paint and scoop away a layer of the paint. And that is basically money down the drain. 

As a result, self-etching primers should not be used over clear coats or existing paint.

The purpose of priming is to prepare the surface for painting by creating a ragged surface for the paint to settle in. 

When Should You Use Self Etching Primer?

Self-etching primer sits well over bare metal. So, you can use self-etching primer when you want to paint a metal surface like aluminum, steel, fiberglass, etc. 

If you are working with automotive paint, that means you are working on a metal surface and that requires a coat of self-etching primer. Automotive paints or paints that are used on cars, steel, metal, etc. all need a self-etching primer to get a nicer finishing. 

Self-etching primer can also prevent rust because of the sulfuric acid in the formula. So, if you want to get rid of metal rust, grab some self-etching primer and apply a coating on the metal surface. 

What Paint to Use over Self Etching Primer?

As self-etching primer is able to scrape away a layer of rust.

For this, it can easily scrape away your applied layer of paint easily. So, clearly, you can’t just use any paint over the self-etching primer. Either you will need a special kind of paint or something to seal over the layer of the self-etching primer. 

Well, there is no such paint invented till now that can sit on self-etching primer without the risk of adhesion, sorry. So, you have to use a layer of another primer or primer-sealer to tuck in the self-etching primer. 

In this way, the primer will be able to prevent rust and you can use any paint according to your choice without any tension.  

How Long Should You Wait Before Painting Over Self Etching Primer?

Self-etching primers are commonly used on bare metal, fiberglass, and aluminum surfaces. 

They differ from normal primers based on many factors but the key difference is, that they etch into the surface to which you apply them.

And you need to wait thirty minutes or 3-4hrs tops before you can paint over it. 

This is due to the presence of a chemical in the primer compound that is responsible for bonding and etching the metal.

A little amount of phosphoric acid is present in the self-etching primers, which chemically burns into the metal. This ensures that the upcoming paint topcoat clings well to the existing surface.

Due to their thin coatings, self-etching primers produce minimal film builds since they are made with low volume solids. They get the job done successfully by maximizing adhesion, despite the fact that they only require a thin coat. 

Furthermore, these primers do not require lengthy preparation.

The self-etching primers offer good corrosion protection because they contain zinc phosphate pigments that form a seal. Etch primers have an extremely short curing period compared to latex and epoxy primers.

Mineral spirits should be used to clean the metal surface thoroughly.

After that, you can sand the surface to smooth it out using either wet or dry sandpaper. You can get a better and smoother finish by wetting the sandpaper. 

After cleaning the sanded area, apply the self-etching primer carefully and steadily while keeping a safe distance from the surface. You can achieve a better grip and a finer appearance by applying two or three more thin coats with two minutes of drying time between them. 

You might also decide to sand the primed surface again after 3 to 4 hours. If you want to paint over the primer, keep in mind that it will dry in 30 minutes and be ready for the topcoat.

What’s the Difference Between Self Etching Primer and Regular Primer?- Explained!

Self-etching primer and regular primer are completely different from each other. Their formula, usage, everything. Let’s see the following table to learn more differences between self-etching primer and regular primer.

A regular primer is a mixture of solvents, binders, and synthetic resins. It has a relatively simple paint formula. There are no specific chemicals or acids in the primer’s formula.

The key ingredient of this formula is the binder in the paint coating. This is what gives it its adherence and binding properties.

On the other hand, the formula for self-etching primer is rather complicated. The primer coating is made up of chemicals and acids. A phosphoric acid ester is a key ingredient in self-etching primer. The acid is in charge of etching things so that the topcoat can adhere.

Regular primer will dry faster than a self-etching primer. Self-etching primer will be dry enough to apply paint on in 4hrs more or less. But regular primer only takes 30 minutes to 2hrs. 

Water-based primers will take less than an hour. But oil-based primers take 90 minutes to dry fully. 

Regular primer is more expensive per unit than a self-etching primer.

But regular primers come in paint cans and self-etching primers in a spray can. So, if we think about the quantity, you will get a better quantity of regular primer than a self-etching primer in one can. 

So, in this way, even though regular primers cost more than self-etching primers per unit, you are most likely to spend more money if you choose a self-etching one. 

For organic-like materials like wood and brick, regular primers are excellent. Regular primer can be used on masonry, concrete, plaster, drywall, and other surfaces.

Metal surfaces benefit from the self-etching primer. Self-etching primer cannot be used on organic materials such as wood since it is designed to etch or corrode the substance, yet wood does not require corrosion. They are used on aluminum, steel, fiberglasses, etc., and many other metal surfaces. 

Regular primers are versatile and can be used with almost any paint. Self-etching primers, on the other hand, are only suitable for use with automotive and metal paints.

Regular primers are more difficult to apply than self-etching primers. As self-etching primers come in a spray can, it’s easier to apply to metal surfaces. Just one coat is more than enough to prepare a surface. 

On the other hand, regular primers come in a paint can, so you’ll need to apply the primer coating with a paintbrush, which will take longer and reveal brush marks.

Regular primers can not prevent rust unless they are covered with a rust-resistant sealer or topcoat. On the other hand, self-etching primer can help prevent rust on metal surfaces. Because the self-etching primer lashes with the metal to form a moisture-resistant coating.

A regular primer is a better sealant rather than a self-etching primer. Regular primers are designed to seal and inhibit stains, moisture, and oils from seeping through the primer covering and paint. However, the self-etching primer doesn’t do a good job as a sealant.

FAQ

Can I wait a week to paint after priming?

Latex primers dry quickly in most cases, usually in less than an hour. You should wait three to four hours before adding another coat of paint. But an oil-based primer will take longer to dry. Give it 24 hours to make sure it’s totally dry before applying another coat.

Should I sand Self Etching Primer before painting?

At some point throughout each major restoration or body repair process, you will need to sand primer. However, the experts do not recommend sanding the self-etching primer directly due to the acid-base of the products.

Can I apply epoxy primer over self-etching primer?

Epoxy is the only primer that can be used with body filler. Body filler should not be applied over a self-etch primer or primer surfacer, but epoxy is completely capable of that. Epoxy Primer is the finest thing to use if you’re going to be doing any bodywork.

Conclusion

Thanks for reading this far with your patience. Hope our article answered your question: can I use self-etching primer over paint. Now that you have your answer, you can paint your automotive or any metal surface without making any waste. 

Just make sure you do proper research on an automotive painting before you do it yourself.