Gundam Tutorials

Top Coating For Gunpla Explained

(Note: This articale was originally published on my site.)

The Top Coat: A Short Play In One Ridiculous Act

The Scene: A downtown cafe… a man sits at a corner table, enjoying his coffee. A friend walks in through the front door…
Man 1: “Hey, how are you? I haven’t seen you in a while!”

Man 2: “Hey! Wow, it has been a while! Mind if I join you?”

Man 1: “No, not at all, not at all. Please sit down.”

As Man 2 walks over, Man 1 notices that he is wearing a long, heavy coat, despite the very warm summer weather outside.
Man 1: “So, I must ask… what’s with the heavy coat?”

Man 2: “What? The coat? It’s a coat.”

Man 1: “Yeah, but… it’s a really warm day. Are you feeling well?”

Man 2: “Couldn’t feel better.”

Man 1: “Yeah, that’s great… so… the coat….”

Man 2: “Well, before I left the house, my wife noticed I wasn’t dressed for going out. She said ‘You need to put something on’, so I grabbed this coat.”

Man 1: “But you’re sweating profusely. That can’t be comfortable.”

Man 2: “Oh yes, it is very hot. Quite dreadfully so, in fact.”

Man 1: “So why didn’t you just put on a t-shirt, or something lighter?”

Man 2, looking puzzled: “What do you mean?”

Man 1: “You know- put on an outer garment that is appropriate for the conditions. You’re not just putting it on for no reason. Your choice of garments should be made with purpose. In the summer, you put on a t-shirt. In the winter, a coat. In the fall, you might use a sweater.”

Man 2: “Wow… that’s some pretty advanced stuff there. So I’m not putting something on simply for the sake of putting something on, but rather for a purpose?”

Man 1: “Exactly.”

Man 2: “That is enlightening. Well, I am very warm in this. Let me shuck this coat off…”

As Man 2 takes off his long coat, Man 1 comes to a horrible realization.
Man 1: “PANTS! You’re not wearing pants! Put the coat back on!”


Ok, I’ll admit, that is a rather silly scenario. Yet I think it’s important to illustrate a basic point- applying a topcoat to your Gunpla (or any model) is for a purpose, just as your choice of clothing (human topcoat!) is for a purpose also. As silly as it seems to wear a long, heavy coat in the summer, if you aren’t comfortable with why a topcoat is needed on your Gunpla, you may be making a choice that is, frankly, just as silly- even if you don’t intend it to be silly at all.

And of course, asking the general question “should I topcoat” can be answered in so many ways, the responses received on groups and forums throughout the interwebs may not always be helpful. Sometimes, in my own experience, it can be difficult to even ask the right question if you’re not familiar with a subject.

Hopefully, I can help sort out the why, when, and what of topcoating, so you won’t (figuratively) walk around on a hot summer day with a long coat on. And no pants underneath. 🙂

(A note: Sharp-eyed reader and Gunpla builder Andy B. pointed out that many use the word “clear coat” for any coat applied during the build process, but “top coat” often refers to the final coat applied to a model. He is absolutely correct! However, for the sake of simplicity, I’ll refer to any clear coat applied during a build as a topcoat, whether it is intermediary or final. Thanks for pointing out the need for clarification Andy! 😉 )

Why bother topcoating?

Topcoating in and of itself is nothing magical. The purpose of a topcoat is to accomplish something else, some intended purpose. So adding a topcoat will generally fall under these categories:

  • Protection- You may want to protect work already finished. It may be sealing it from damage, or against later applications of paint, weathering, etc. An example would be to protect the base paint against another coating, such as a wash.
  • Preparation- Some topcoats are applied to prepare the surface for a particular technique to follow. An example would be the use of a gloss coat to prepare parts for decals.
  • Protection AND Preparation- Many times, a topcoat application accomplishes both of the previous reasons at the same time.
  • Finish- Some topcoats are applied as a final step in the build process, to achieve a certain overall surface finish, such as a matte coat to take away the shine on a model.

While there are certainly a great range of answers to the “why” of topcoating, most will fall under those four categories. Of course, now that we’ve established why a topcoat is applied, that moves us on to…

When do you topcoat?

Now we’re getting to the heart of the matter. Knowing when to topcoat is of critical importance. Applying a topcoat just any old time can be a waste of money, time, and even create problems in later steps of finishing a model.

While there are certainly more nuanced reasons for the “when”, here are some of the most common times to apply a topcoat:

  • Prior to decals- Most decals will adhere better to a glossy, smooth surface than to a matte, rough surface. A gloss topcoat, applied before you add your decals, will help them adhere much better, and avoid silvering.
  • After decals- the best way to seal your decals after application is- another topcoat. This will proect them from staining after applying a wash, or damage from handling.
  • Prior to using a wash/filter- While an explanation of applying filters and washes is beyond the scope of this article, it is essential generally to apply a coat over the part or model prior to using these techniques. In most cases, a glosscoat is applied, though a matte coat may be desired to achieve a particular effect.
  • After a wash/filter has been applied- Many times I will apply a topcoat after a wash/filter to make sure they stay in place.
  • Prior to a coat of a similar medium- Let’s say you wanted to apply an enamel filter over your model, to give it a bit of a tint, and add subtle streaking and shade variations. Once that was applied, you may want to then apply a panel line wash, using enamel washes. If there is no barrier between the filter and panel line wash, the thinners in the wash may reduce or remove the filter already applied. By topcoating the filter, you protect it against the panel line wash.
  • When a technique requires a different surface texture- Gloss coats are great for decals, but not so good for drybrushing and edge highlighting. So you need to evaluate what surface texture a particular layer in your finish process requires, and apply that.
  • When you finish your model- I like all of my models to be ultra-matte. Sometimes you may want a glossy look, or even a satin look. While that is certainly a matter of personal taste, it is generally a good idea to do some form of topcating at the end of a build, both to achieve the final finish that you desire, but also to seal it all in for protection. This can be especially critical for Gunpla builders- all of those cool action poses require a lot of handling!

As with the “why”, the number of answers for “when” can certainly vary from those above. Those are the general cases, of course, but for most builders, the instances listed cover the majority of scenarios a Gunpla builder will encounter.

So with the why and when sorted, that brings us to…

What do you topcoat with?

While the previous two sections could certainly generate varied opinions, experiences, and observations, this one can often be a very hard line for many people. You may hear someone say “never use that gloss topcoat”, and someone else say “always use it!’ And you are left wondering which one is right.

Frankly, neither. At least not in a 100% sense.

As with any product you use in Gunpla, the “what” can vary by product availability, region, personal skill level, past experience, and even climate can play a small part. So to try and state, categorically, that XYZ Gloss Coat or ABC Matte Coat is the best ever would be dishonest. You may have to experiment a bit. With experience, you’ll likely find a group of products that work best for your needs. But as with the other topics we’ve examined, here are some general categories.

First, there is the type of topcoat to consider:

Acrylics- Generally, these topcoats are water based, easy to apply, and in most cases are sufficiently durable enough for most modeling uses. While they are not particularly odoriferous, when airbrushed, they are not safe to breathe, so always use proper ventilation and wear a mask. They are friendly to almost anything they are applied over- other acrylics, enamels, or lacquers.

Enamels- As you would likely guess, these types of topcoats are enamel based. They tend to be a bit more durable than acrylic topcoats, but their odor can be very strong, and many find them unsatisfactory for that reason. If applied carefully, they can be used as a topcoat for most mediums, though I have seen cases where a heavy handed application reacted with previous enamel coats in a bad way.

Lacquers-  No surprise here, these use lacquer based thinners as their carrier medium. They tend to go on very, very smooth, smell awful, and of the three types discussed here, generally have the highest probability for a bad reaction with previous layers. And they can eat bare plastic alive if you’re not really, really careful. Having said that, in my experience, they are very durable when fully cured.

In addition to the types of topcoats, we need to examine the finishes they offer:

Gloss- Shiny and smooth, though with some qualification. If your base coat is rough and textured, your gloss coat on top of that may not be as shiny or as smooth as you hoped for.

Matte- Dull in finish (as in not shiny… I’m sure given the opportunity they have quite the personality), these can range from reasonably smooth to a bit grainy, depending on what is under them, how it is applied, and the type of product being used.

Satin- This is the finish that can’t make up its mind. While it is something between gloss and matte, it’s often best utilized to impart a more realistic “shine” to a finish. For example, when viewing a real object- say an airplane- from a distance, it may not necessarily be glossy, but you can still see reflections in its surfaces. That’s more of  satin finish.

So evaluating what you should use to topcoat your Gunpla  with involves two basic questions- what is the purpose of the topcoat (wash? decals? flat finish?), and what is under the topcoat.

The decision of gloss or matte is generally easy- decals, washes, and similar applications do best with a gloss coat, while drybrushing, heavy oil staining, and a final flat finish call for a matte coat.

What type of coat- acrylic, enamel, or lacquer- is a more critical issue. Applying a very “hot” topcoat, such as a lacquer based one, over an acrylic, for instance, can lead to bad results. The decision here is very subjective, as it depends highly on what type of paint you use most often. If you use lacquers, then a lacquer or enamel based topcoat may be the best option. With enamels and acrylics, an acrylic topcoat is probably a good choice. Ultimately, opt for the least reactive choice.

Wrapping up

As with anything in building Gunpla, a good understanding with of topcoating will take some practice, and probably making a few mistakes. But with a bit of practice, you’ll find that there really is no mystery to topcoating- it’s simply a tool to use in your finishing process.

A few basic questions to keep in mind may be helpful:

  • What is going ON the topcoat?
  • What is UNDER the topcoat?
  • What will come after that?

Evaluating your build in those terms will help you understand why you’re topcoating, when to do it, and what to do it with.

Finally- my own personal experience… for what it is worth.

For paint, I only use acrylics. I employ filters and panel line washes with both acrylics and enamels. I only use acrylic topcoats. For gloss coating, I use Future/Kleer, and for satin and matte coats I use Vallejo or Ammo of Mig acrylics. In over 250 model builds over the last decade, these have served me well with no problems. I say that not to advocate for what you should do, but simply to pass along what I do.

Topcoating is a great technique to employ for a wide variety of purposes. With practice, you’ll be a master topcoater in no time!

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