Gunpla Decals and Decal Setter

The three types in the box

Foil stickers. Pre-cut, adhesive-backed, often with a metallic foil layer. Peel and press. They are in almost every High Grade kit, they take no skill, and they look like what they are — a thick opaque patch sitting on top of the plastic with a visible edge that catches light. Fine for a first kit, and the reason most builders conclude they dislike decals.

Dry transfers. A carrier sheet you position and then burnish from behind with a blunt stylus, transferring the ink directly to the surface. No film at all, so no edge and no silvering. The catch: one shot. Once it is down it is down, and a misaligned transfer has to be scraped off.

Water slides. Printed on a thin clear film on backing paper. Cut one out, soak it in water for ten to thirty seconds, and the film releases and slides off the paper. Position it wet, blot it, let it dry. The film is thin enough that once sealed the marking looks printed onto the armour. This is the one that looks good, and the one that needs technique.

Applying a water slide properly

Trim close. Cut the decal out with a sharp blade leaving the minimum clear film around the printed area. Every millimetre of excess film is a millimetre that can silver.

Soak briefly. Ten to thirty seconds in room-temperature water is enough for the glue to release. Over-soaking washes the adhesive away entirely and the decal will not stay put.

Slide, do not lift. Rest the backing paper against the kit and push the film off sideways with a damp brush or a cotton bud. Lifting a wet decal with tweezers is how they tear — use the tweezers to hold the paper, not the film.

Position with water underneath. While the surface is wet you can nudge the decal for a minute or so. A drop of water under it buys more working time.

Blot, do not rub. Press a cotton bud or soft tissue straight down to draw out the water and push out air. Rubbing drags the film and wrinkles it.

Silvering, and what setter actually does

Silvering is the dull metallic haze around a decal. It is not a printing fault — it is microscopic air trapped between the decal film and the surface underneath, reflecting light. A matte surface silvers far worse than a gloss one, because a matte finish is microscopically rough and the film cannot sit flat against it.

Two fixes, and they stack.

Gloss first. A gloss coat under the decal gives it a smooth surface to bed onto. This is why painted kits get a gloss coat, then decals, then the final finish — the sequence explained in matte vs satin vs gloss topcoat.

Setting solution. Decal setter softens the film so it relaxes and conforms to panel lines, rivets and curves, driving the trapped air out as it shrinks down. Applied over the top after positioning, it looks alarming — the decal wrinkles badly for a few minutes — and then dries flat and welded to the surface. Do not touch it while it is wrinkled; that is the stage where decals get destroyed.

Setter and softener are sold as pairs by several brands; a mild setter under the decal and a stronger softener over the top is the classic two-bottle approach, and either on its own is a big improvement over neither.

Where decals go in the build order

Unpainted kit: build, panel line, decals, topcoat.

Painted kit: paint, gloss coat, decals, setter, panel line, final topcoat.

Panel lining after decals on a painted kit lets you run a line across a decal so the marking sits in the panel rather than on top of it. The lining technique itself is in how to panel line Gunpla; be aware that enamel liner can attack an unsealed decal, so the gloss coat matters.

Sealing: the step that makes them disappear

An unsealed decal is a slightly raised patch of film that can be scratched off with a fingernail. A sealed one is under the same finish as the rest of the armour, which is what removes the last visual trace of an edge.

A semi-gloss lacquer clear is the default Gunpla finish and the usual choice. If the room is humid, a water-based top coat avoids the frosting risk entirely — lacquer clears blush white above roughly 65% relative humidity, which is the most common way a finished kit gets ruined at the last step. Both routes, and the humidity numbers, are covered in the topcoat picks.

Should you use decals at all?

On a straight build with foil stickers: your call, and leaving them off is a legitimate look. Plenty of clean builds skip markings entirely.

On a painted kit: yes. Markings are what make a Gunpla read as a machine with a unit number rather than a toy, and water slides plus a sealed finish are what separate a built kit from a finished one. If you are working through a first painted build, the sequence fits directly after the steps in how to paint your first Gunpla.

Storing decals, and what to do when they yellow

Decal sheets age. The carrier film yellows with light exposure and the adhesive loses strength, which is why the sheet in a kit bought a decade ago often tears or refuses to release.

Store sheets flat, in the dark, somewhere dry — a folder or a zip bag in a drawer is plenty. Heat and sunlight are what age them.

A yellowed sheet is sometimes recoverable: a few days under a bright daylight lamp or on a windowsill can bleach the film back toward clear. It is slow and it does not always work, but it costs nothing and the alternative is a sheet you cannot use.

If the adhesive has failed and decals float free without sticking, a coat of decal film solution or a thin brush of gloss varnish over the sheet before cutting restores a usable carrier. Soak as normal and apply with setting solution.