How To Apply Waterslide Decals To Gundam Kits

“How do you apply waterslide decals?” is one of the number one questions we get here at Gunpla 101. They may be different from stickers, but they’re not that much more complex—and the visual payoff is worth the effort to learn a new skill. Follow along with Gunpla 101 contributor chennerbot to master waterslide decal application. 

What do you do with a naked Gundam kit?

And by naked, we mean a finished kit that has no stickers or decals of any kind. So if you got to this page by searching for naked robots… sorry the algorithm led you here. We’re putting decals on a Real Grade Wing Gundam today, and I promise it’s just as interesting a topic!

Waterslide decals can give your Gunpla kit that extra visual oomph you are looking for. But flipping through various Gunpla groups on Facebook and Reddit, I’ve noticed some folks seem really intimidated by the process. Let me assure you—it can be a pretty fun and relaxing endeavor if you’ve got the right tools and a regimented process.

Tools for applying waterslide decals

You can make applying waterslide decals as expensive or as cheap as you want it to be. I think it’s important to be considerate of everyone’s budget levels, so I’ll break this up into two sections: what I consider “must have” accessories and “nice to have” items.

Must Have

• Hobby knife or small scissors. I personally find a hobby knife preferable to the small scissors; it allows me to cut a rectangle directly around the WSDs that I am going to work with. Scissors may require some maneuvering around the sheet of decals – the sheet will end up extremely cut up, and you may lose parts of the sheet while you are working.
• Tweezers. Some decals are really tiny. Using tweezers should help you effectively grab and position the decals.
• Short brim cup or other container for water. You’ll need water to activate the decals.
• Cotton swabs. Use these after the decal is applied and where you want to absorb any excess water to help the decal dry quickly. You can also use these to push out any air bubbles underneath the decal.
• Toothpick. Many folks prefer toothpicks to move and reposition waterslides.
• Waterslide decals (of course 🙂). Yep, we’re committing to this.

Nice to Have

• Mark Softer or MicroSol. Mark softer is really helpful to help decals curve around corners or a curved surface. It also helps if you notice the decal is not perfectly flat.
• Mark Setter or MicroSet. Mark setter is fantastic in helping the decal adhere where you want it to.
• Waterslide Decal Tray. This was a game changer for me; get one with the sponge underneath where the decals sit. It helps keep your decals wet so they don’t dry out. This becomes a huge time-saver once you get comfortable with your process and can cut out multiple sets of decals at a time. More on this below.
• Third party waterslide decals (Delpi or G-Rework highly recommended). I am a big proponent of third party decals. They release faster from the backing paper. Unlike the Bandai offerings, they do not require warm water to activate, and in my opinion, are much sturdier. For certain kits, you also get “extra” decals not included on the Bandai sheet to customize your kit a little bit more (see the waterslide picture below – these are designated by numbers in a red circle). Finally – some kits have the option of different color or finish options. We’re working with some holo/foil decals on the Wing Gundam today.

Process for applying waterslide decals

When I first started out applying waterslide decals, I would haphazardly go around the kit applying the “cool” stickers first: shoulder markings, big logos, and anything else that would catch the eye. Then I’d move on to the small marking decals. After a kit or two, I noticed that many of these decals would have shifted, moved, or sit awry. I realized that I was inadvertently moving these decals before they were set by handling the kit so much.

With my more recent builds, I have started to work from top to bottom, no matter what. Not only has this smoothed out my workflow, but the decals are now (magically?) staying where they should. I will generally move in this order while the kit is laying flat:

1. Front of kit, top down, left to right. (Note: I am right handed. Moving left to right helps me avoid bumping any freshly applied decals if I applied right to left.) 
2. Take a break, go get yelled at by my kids, grab a snack… (AKA let the decals dry)
3. Back of kit, top down.
4. Repeat step 2, or go work on weapons and accessories.
5. Sides of kit.
6. Repeat step 2 or 4.
7. Any other regions (ie arms, top of shoulders…etc).

Once the decal is down, you can use a toothpick or your tweezers to shift to the desired location. Then I recommend using a cotton swab to push down on the decal. This should eliminate any air bubbles and pick up any excess water to help it dry faster. It’s very important that you push straight down and pull straight up, otherwise you may shift the decal and have to do some extra work to reposition.

You’ll notice air bubbles a lot more on the larger waterslides—again, some Mark Softer should help smooth these out.

Mark Softer/Mark Setter

These are both chemicals that help make your job easier; the underside of the cap has a small tube and brush to help you apply the solution to where you need it.

Once I’ve identified where the next decal is going, I’ll apply a small dot of Mark Setter to the location. This helps the decal transfer to the surface of the kit. If you are having trouble getting decals to transfer to the kit and don’t want to spend on Setter, you can apply a small drop of water to the decal location to help the waterslide “grab” onto the surface. As you can see below, I’ve applied a small drop to the center of the shield.

Mark Softer is a really handy chemical that subtly melts the waterslide. Note that once you apply it, you want to handle the decal as little as possible, as it becomes more prone to tear. I’ll break it out in the following situations:

1. Applying to a curved or corner surface.
2. A decal that is having trouble sitting flat by itself.
3. The edge of the decal visually stands out—Mark Softer will dissolve the edges.
4. There are a lot of air bubbles under the surface.

Here’s a use case scenario below. The red triangle on the right foot (our left) below is not sitting quite as flat as I would have liked, so I put a little drop of Mark Softer on it, gave it a nice firm push with a cotton swab, and now it’s nice and flat. Note, with the holo/foil decals I’m using today, the light may catch it weird and it may not look flat or aligned… but it is!

Waterslide Decal Tray

Again, I cannot recommend this thing enough. As you move through a kit, you may notice regions where you have paired or duplicate areas. You can cut out multiple areas at once, set them on the tray, and wait for them to release. Once they do, the sponge keeps them wet so they do not dry out.

In the image below, you’ll see that multiple locations on the shoulders are paired together: 23 and 24, 4 and 5, and 48 and 49. These zones are also on the back of the kit. The beauty of the layout on the waterslide sheet is that they are all paired or near each other. So I cut out a pair of each number (two 23s, two 24s, etc), waited for them to release, and then stuck them on.

The legs have four zones that require decal 25, so I cut four of these out at the same time. Huge time savings here.

Well—that’s it. Hopefully at this point you’ll have a partially or fully dressed Gunpla model. Drop any comments below if I can help answer any questions you may have.

Creeping towards a midlife crisis, chennerbot is supplanting the urge to buy a convertible Corvette by building plastic robots.