How to Panel Line Gunpla

What panel lining does

Injection-molded kits have recessed lines representing panel joins, hatches and vents. On bare plastic they are nearly invisible because the surface is one flat color with no shadow in the grooves.

Panel lining puts a dark line in those recesses, which reads as shadow and makes the surface detail pop. It is the single highest-impact thing you can do to an unpainted kit, it costs one bottle, and it takes about ten minutes for a High Grade kit.

The three methods

Enamel panel liner. The standard. A thin, pre-mixed enamel that flows into recesses by capillary action and wipes cleanly off flat surfaces with enamel thinner. The best-looking result and the method with the most control — and the one with the plastic caveat below.

Panel line markers. A fine-tipped pen you draw into the groove, wiping mistakes with an eraser or a damp cloth. No thinner, no fumes, no risk to plastic. Slightly less refined on long curved lines, and the ideal starting point — see the marker picks.

Acrylic wash. A thinned dark wash brushed over the area and wiped back with a damp cloth. Cheapest if you already paint, safest for the plastic, and the hardest to control because acrylic grips the flat surface as it dries.

The wipe-away technique, properly

Nearly all panel-lining failures are wiping failures. The sequence that works:

1. Apply sparingly. One touch into the recess and let it run. Flooding a whole panel and planning to wipe it all back is the hard way.
2. Wait until the surface is dry to the touch but the liner in the recess is not fully cured — a few minutes, not an hour.
3. Barely damp cloth. A cotton bud or cloth with the smallest amount of enamel thinner. Wet means you pull the liner back out of the groove.
4. Wipe across the line, not along it. Wiping along the groove drags the liner out; wiping across it leaves the recess full and cleans the flat.
5. Reload the cloth often. A dirty cloth smears the color you just removed across the next panel.

If you take too much out, just reapply. This is a fully reversible stage, which is part of why it is such a good first finishing technique.

The warning: enamel thinner and stressed plastic

This is the part beginners are rarely told, and it ruins parts.

Enamel thinner can seep into plastic under mechanical stress and cause it to crack — classically at peg holes, thin joints and areas where a part has been forced on. The crack may appear days later.

Three precautions. Keep thinner away from joints, peg holes and any part that visibly flexes when assembled. Where possible, line parts before final assembly rather than after. And on ABS-heavy inner frames and load-bearing joints, use a marker or an acrylic wash instead — neither carries this risk.

Restraint is the skill

Not every recess wants lining. Lining every molded groove on a kit makes it look like a diagram rather than a machine.

Line the lines that represent real panel joins and hatches. Skip the shallow surface scribing. And consider color: pure black is heavy on light and mid-tone parts, where a dark gray or brown liner reads as shadow instead of ink. Many builders keep black for white armor and gray for everything else.

When it is done, seal it. A matte topcoat stops the lining rubbing off with handling and removes the plastic gloss — the two steps together are what make a snap-fit kit look finished without any paint at all.