Do You Need to Prime Gunpla Before Painting?

Painting can be daunting for beginner modelers as it includes many steps such as priming, base coat, top coat, and buffing. Thus, some tend to skip priming since it looks like it’s unnecessary. However, is priming optional, or do we really need to prime Gunpla models before painting?

You should prime your models before painting because it provides a sticky surface for the paint. This prevents chipping that can happen in the future, prolonging your paint’s life. Furthermore, priming removes scratches on the body to make the surface smooth. For these reasons, priming is necessary before painting.

This blog post will discuss the benefits of priming your models. I am excited to share these benefits as they also helped me with my builds. Let’s start!

Do You Need to Prime Gunpla Before Painting?
HG Neo Zeong Gundam Painted with Primer

Why is Priming Necessary on Gundam Models?

Priming is necessary if you want to paint your Gundam models because it helps the paint last longer. Furthermore, primers act as a filler to remove scratches on the body. However, priming shouldn’t be done if we won’t paint the model.

Here are the reasons why priming is necessary when painting models.

1. Primers act as the bridge between the paint and the body

When you start asking people why they prime their models before painting, they would usually answer that primers serve as the bridge between the paint and the body.

This is because the primer’s main job is to stick to the paint and the body. This ensures that the paint lasts longer as it will stick to the body properly because of the primer.

But why? Well, paints don’t usually stick well on the plastic’s surface. That’s why priming is essential.

While they look like they stick after painting, paints can fall off easily, especially if you try rubbing painting jobs that aren’t primed.

Furthermore, if we let the paint sit for long periods, it can chip because they don’t properly stick to the model.

This is the main reason why primers are crucial to the painting process. They make the paint last longer as they won’t easily chip from the model.

However, you might have heard from other people that some paints don’t require primers as they tend to be fine without them.

That’s true, and not all paints need priming. But priming enhances the paint’s adhesiveness, making them last longer.

But why do many modelers still use priming if some paints don’t require them? Well, let’s talk about that in the next section.

Mg Ex Gundam Painted with Primer
Mg Ex Gundam Painted with Primer

2. Primers protect the body from the paint

Primers protect the body from the paint since paints can harm the plastic or the body because they are made with numerous chemicals. In addition, paints such as lacquer and some enamel can accelerate plastic aging leading to brittleness.

Because of this, modelers protect the plastic by covering them with a primer before painting.

Earlier, I discussed that priming is not necessary since some paints tend to stick well to the body even without a primer.

That is true with enamel paints. Enamel paints tend to stick to plastics even without a primer. However, primers help enamel paints stick better.

But this is not the most important reason why you should still prime with enamel paint even if they can function alone.

Some enamel paints have some bad effects on plastics because of their chemical components. These paints can make your plastics brittle even if they are still new.

Primers serve as the shield between the paint and the body. By doing so, we can use enamel paints without worrying that they can harm the body.

This is also true of lacquer paints which you can usually find on spray cans. Almost all lacquer paints can react with plastics leading to brittleness. Thus, it is essential to prime your models before using these paints.

Remember that plastic aging is irreversible. So, we have to protect the models from harm by priming.

Recommended Read: I talked about lacquer and enamel paints being slightly harsh on models. The truth is there are three general types of paints used for Gunpla models. If you want to know them, feel free to check this post: Paints you can use for Gunpla Kits.

3. Primers make the paint durable

As we already discussed, primers make the paint durable by functioning as a bridge between the body and the paint.

Priming your models can add years to the paint’s life as the paint won’t chip off easily.

Simply put, the primer provides a sticky surface for the paint to adhere to. This keeps the paint last longer and saves time as modelers don’t need to repair their models every few months.

PG Unicorn Painted with Primer
PG Unicorn Gundam Painted with Primer

4. Primers Acts as a Filler

Another thing people seldom notice is that primers offer some filling. Thus, they remove scratches which results in a smoother surface.

Sometimes, we make mistakes while building our models. For example, we might scratch a part because we accidentally hit it with a hobby knife.

I have known that since it happened to me. There was also a time were I accidentally scratched the part with a model nipper.

These minor scratches can be removed with primers as some fillers, particularly the acrylic urethane primers, can fill these spaces.

Another thing primers can remove is stress marks. You see these nubs when you cut the model part from the gate.

These are discolorations that happen when you introduce some crushing force to the gates.

Here is a photo of a stress mark I’ve purposefully made.

Stress Marks that can be removed with priming and painting
Stress Marks that can be removed with priming and painting

Priming and painting can remove these marks in a few seconds because it covers them and acts as a filler.

Recommended Read: The stress mark in the above photo was removed without using paint and primers. I did that with multiple sandpapers and a plastic protectant. If you are interested in how I did that with a video tutorial, please check this post: How to remove stress marks on Gunpla models?

5. Primers add vibrance and shade to the color

When you go to paint shops, you often notice that primers come in many colors. These colors are there for a reason.

Primers add some vibrance and shade to the color. Usually, the paint will have some shaded color depending on the primer.

For example, if the primer is green, the paint will have some greenish shade after painting. On the other hand, if the primer is red, then it will have a reddish hue.

Primers have more than 20 different colors, but as a beginner, you should only use three colors.

Here is the basic rule of priming. Basically, only use three primer colors as a beginner: white, gray, and black.

Use white if you want a matte finish and black for a shiny finish. Gray sits in between, and I recommend the gray primer for general purpose.

Other colors can be used, but you would never go wrong with these three colors.

Going for the green, red, or pink primers is for advanced modelers, and I recommend testing them with a spoon before using them on your model since they will affect the final color.


As we can see, priming offers many benefits for the model. This is especially true if you want to paint your model.

However, make sure to prepare your models before priming since most plastic kits are covered with something called a mold release. This mold release prevents the primer from properly sticking to the model.

If you want your primers and paint to last for years without chipping, wash your models before priming.

Washing removes the mold release, preventing the primer from sticking to the body.

Recommended Read: I created a tutorial with a video in a separate blog post about washing your Gunpla models. This step is crucial if you want to prime your models. If you’re interested, you may check the post here: How to wash Gunpla models? Why should we wash them?

If you don’t have a primer, you can also skip priming by sanding your model. However, this alternative is very tedious and wastes a lot of time. That’s why most modelers agree to use primers instead.

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