Gunpla Panel Lining: Markers vs Wash, Step by Step

Every Gunpla kit is molded with recessed panel lines, the thin grooves that suggest armor plating and mechanical detail. Out of the box those lines are the same color as the plastic around them, so from a few feet away they barely register. Panel lining means running a dark (or sometimes light) line of ink, paint, or pigment into those grooves so they catch shadow and actually read as detail.

It is separate from painting the kit. You can panel line a fully unpainted, snap-together build and it will look dramatically better for almost no extra effort. That is why it is usually the first "real" technique people learn after nippers and a hobby knife.

Gundam Marker covers several different products. The fine-tip GM01-03 liner pens let you trace a panel line directly; Mr. Hobby specifies a rubber eraser for overflow. The GM301-303 pour-type markers use flowing ink, can affect paint underneath, and should not be used on ABS parts. Check the exact range before choosing your method.

The appeal of the fine-tip pens is that there is no mixing and you control exactly where the line goes. Check the plastic and test first. Tight curves and small parts still take a steadier hand than they look like they should. I keep a gray and a black marker on the bench at all times because between the two you can line the vast majority of any kit.

An enamel or oil wash is a thinned paint you apply with a fine brush, letting capillary action pull it into the panel line, then wipe away the overflow with a cotton bud lightly dampened with the cleanup product specified for that wash. Because the wash is thin and flows on its own, it tends to produce finer, more consistent lines than a marker tip can manage, especially on tight detail.

The real caveat is that enamel liner can make plastic brittle. Tamiya specifies its Panel Line Accent Color over a lacquer or acrylic base coat, warns against using it on moving parts, and calls for care around load-bearing areas. Even the base coat needs a compatibility test. That extra preparation is what makes enamel washing feel like a step up in commitment from a fine-tip marker.

For fine-tip markers on compatible unpainted plastic, panel lining usually comes before a finishing coat. Test the exact ink and clear-coat combination first; a compatible flat or semi-gloss coat can seal the line and even out the sheen.

For enamel or oil washes, I lay down a compatible gloss coat first, before the wash goes on. A smooth surface helps the wash flow and makes cleanup easier, while a suitable base coat reduces direct exposure of the plastic. It does not guarantee protection from cracks, especially where liquid can reach joints or bare seams. Once the wash is cleaned up and dry, a tested, compatible finishing coat can unify the sheen.

For GM01-03 fine-tip markers, Mr. Hobby specifies a rubber eraser for overflow. Other marker ranges have different cleanup methods, so use the instructions for the one in your hand rather than treating every Gundam Marker as the same ink.

For Tamiya Panel Line Accent Color, use a little enamel thinner on a cotton bud after the liner dries. Test that cleanup step on your base coat first, keep it out of joints and seams, and avoid soaking the surface. If a line goes wrong, stop and check the liner and paint instructions before adding more solvent; cleanup can damage the finish as well as remove the line.

If this is your first few kits, start with a fine-tip Gundam Marker in gray or black after checking the plastic. It gives you direct control and a simple way to add detail. Once you are comfortable and want flowing lines on a kit with intricate paneling, try an enamel or oil wash over a tested, compatible base coat.