The Complete Beginner's Guide
The fastest way to make any Gunpla or scale model look dramatically more realistic — and you can do it in under an hour on your very first try.
Panel line washing is the technique that separates a freshly built kit from a finished model. It takes the flat, uniform plastic surface that comes out of the box and gives it depth, shadow, and structure — the visual difference between a toy and a display piece. If you've ever looked at a photo of someone else's Gunpla or armor model and wondered what they did to make it look so real, this is usually a large part of the answer.
This guide covers everything: what panel lining actually does, which liner to use for which kit type, how to apply it correctly, and how to fix the mistakes that every beginner makes the first time. By the end, you'll have everything you need to panel line your next build with confidence.
What Panel Line Washing Actually Does
Scale models — and Gunpla especially — are covered in engraved recesses: the lines, joints, vents, and mechanical details that define the surface. Under flat overhead light, those recesses are nearly invisible. Panel line washing fills those recesses with a thin, dark fluid that dries in place, creating the visual shadow that makes every detail pop.
The result looks like the model is lit from above — because in real life, recesses catch shadow. The wash mimics that shadow artificially, making the model appear more three-dimensional and believable at any viewing distance.
Panel lining is not painting. You're not changing the color of the surface — you're adding shadow to the structure that already exists. A single panel line wash session can take a model from "finished kit" to "finished model" in less than an hour.
The Two Types of Panel Liner: Water-Based vs Enamel
This is the first decision every builder has to make, and it matters more than most beginners realize. Panel liners come in two main formulations, each with real advantages and one critical trade-off.
Thins and cleans up with water. Safe on bare plastic, safe on acrylic paint. Easy to wipe away with a damp cloth or cotton swab while wet. No solvent risk. The recommended starting point for most builders.
Thins and cleans up with enamel thinner. Flows exceptionally well into recesses. Best removed with lighter fluid or enamel thinner. Solvent can damage bare or stressed polystyrene if it pools in seams and joints.
Be careful with enamel panel liner on bare plastic. Enamel solvent can attack stressed polystyrene if it pools in seams or joints. On painted models, let the paint cure fully and use a compatible gloss or satin clear barrier when needed; the smoother finish also improves capillary flow and makes cleanup easier. On bare plastic, use a water-based liner or follow the liner manufacturer's compatibility guidance.
For most builders — especially beginners and Gunpla builders working on kits without primer — water-based panel liner is the right choice. It's safer, easier to control, and produces excellent results without the solvent risk of an enamel wash.
The Stedi Acrylic Panel Liner: What Makes It Different
The Stedi Acrylic Panel Liner has become one of the most popular water-based options in the Gunpla and scale modeling community. It's engineered specifically for recessed panel line work rather than being a generic wash repurposed for the task.
It uses an acrylic formula designed to flow into recesses. In practical terms, you can touch the brush to the start of a panel line and let capillary action carry much of the liquid along the groove. You don't need to scrub it into the line; guide it and add more only where the flow stops.
| Color | Best Used On | Effect |
|---|---|---|
| Black | Light grey, white, bright colors | Maximum contrast, deep shadows |
| Dark Brown | Military armor, earth tones, sand | Natural shadow, weathered look |
| Dark Grey | Blue, purple, green, mid-tone bases | Subtle shadow, less stark than black |
| Olive | Military vehicles, green schemes | Tonal depth without high contrast |
| Dark Blue | White Gunpla, blue mecha | Cooler shadow, popular for mecha builds |
Stedi also offers a fluorescent panel liner range — useful for sci-fi builds, mecha models, and glowing accent lines under UV light. The UV Light + Fluorescent Panel Liner Set bundles the paint and light together.
How to Apply Panel Liner: Step by Step
The technique is simple. The details are what separate a clean result from a messy one.
- Prepare the surface. The kit should be clean and dust-free. If you're using an enamel wash over paint, make sure the paint is fully cured and use a compatible gloss or satin clear barrier when needed. For Stedi acrylic liner, bare plastic is fine. Handle parts by the edges to avoid oils from your fingertips.
- Load the brush lightly. Dip a fine-tipped panel liner brush into the liner. Wipe off the excess on the rim of the bottle — you want a loaded tip, not a dripping one. Too much liner makes cleanup much harder.
- Touch the brush to the recess, not the surface. Place the very tip of the brush at the start of a panel line and hold it there for a second. Capillary action will pull the liner along the recess. Let it flow rather than painting it along like a normal brush stroke.
- Work one section at a time. Do all the panel lines on one face of a part before moving to the next. This keeps cleanup manageable and lets you see immediately where excess liner has pooled.
- Let it set according to the product you're using. Cleanup timing varies by formula. With a water-based liner, remove excess while it is still easy to reactivate; with enamel products, follow the manufacturer's drying and cleanup guidance.
- Clean up the flat surfaces. For Stedi acrylic, use a cotton swab lightly dampened with water and wipe across the line with gentle strokes. Keep rotating to a clean section of the swab so you lift excess instead of smearing it around.
Water-Based vs Enamel: Application Differences
- Suitable for bare plastic when the manufacturer specifies it
- Clean up with water or a damp swab
- Re-workable while wet
- Beginner-friendly and low odor
- Often needs no solvent-resistant barrier
- Flow varies with surface and formula
- Excellent capillary flow on a smooth surface
- Clean up with the compatible solvent
- Paint underneath should be fully cured
- Bare/stressed polystyrene can be vulnerable to pooled solvent
- More ventilation is needed
- A compatible gloss or satin barrier can make cleanup easier
Common Mistakes and How to Fix Them
Work in smaller sections. If a water-based liner has dried, a slightly damp swab may reactivate it; for other formulas, use only the cleanup method recommended by the manufacturer rather than scrubbing aggressively.
Usually there is too much liner on the brush, or the surface is too matte and porous for clean capillary flow. Use less material and, when appropriate for your paint system, work over a smooth cured gloss or satin finish.
The recess may be shallow, the liner may be too thick, or the surface may be dirty. Clean the surface first and use only a thinner that is compatible with the liner you're using.
The swab is probably carrying too much pigment. Rotate to a clean section after each pass — or use a fresh swab — so you're lifting residue instead of spreading it.
Pro Tips for Cleaner Results
A fine DSPIAE panel liner brush gives you a small, controllable reservoir of liner and makes it easier to touch the liquid precisely into a recessed line.
Black works well for strong contrast on pale colors. Dark grey, brown, olive or blue can look more natural when you want the line to read as a shadow rather than a black outline.
If your wash will need repeated cleanup, doing the main panel lining before delicate decals can reduce the chance of damaging them. If you want a wash to run over and around decals, let them settle fully and protect them with an appropriate clear layer first.
After the liner and any decals or weathering are fully cured, a final compatible clear coat can unify the finish. Matte is common for military subjects, while satin or gloss may be more appropriate for other builds.
Tools and liners mentioned in this guide
Related Posts
How to Sand Scale Models: The Step Most Beginners Skip
Scale Modeling for Beginners: The Honest Guide
DSPIAE ES-A vs ES-A PRO: Which Electric Sander Should You Choose?
Tools For Scale Modeling 2 — Intermediate Level
