Hand Painting Gunpla: 3 Paint Types, 1:1 Thinner, $3.95

Gundam Color's own maker says to thin it 1:1 for the brush, which surprises builders who paint straight from the bottle. Hand painting Gunpla starts with one choice that decides the rest: solvent paint with a strong smell and fast drying, or water-based paint that is gentler for a first kit.

Key Takeaways

• Three families: solvent Mr. Color (and UG Gundam Color), water-based HUG Gundam Color, Tamiya Acrylic.
• Brush ratio: GSI Creos gives 1:1 for Gundam Color, 1 : up to 1 for Mr. Color.
• Brush marks: a few drops of Mr. Retarder Mild slow drying, the maker says.
• No mixing: UG and HUG do not mix; Mr. Color mixes only with Mr. Color and GX.
• US prices, Oct 24: bottles $3.50 to $4.00; thinner 250 ml $10.00.

Overview: hand painting Gunpla with three paint families

Mr. Color and Gundam Color (UG). GSI Creos's Mr. Color is a solvent-based acrylic resin paint, on sale for over 40 years. It dries fast and leaves a hard, glossy film. The UG Gundam Colors are part of the same family and thin with Mr. Color thinner.

Water-based Gundam Color (HUG). The HUG01-09 line keeps the Gundam Color hues on an Aqueous Hobby Color base, "with less solvent and a milder smell", and GSI Creos calls it ideal for first-time painters (our translation). It thins with water or Aqueous Hobby Color thinner.

Tamiya Acrylic. Tamiya says its acrylics "are made from water-soluble acrylic resins and are excellent for either brush or spray painting." Its dedicated thinner, X-20A, handles thinning and cleaning.

Diagram: PlamoDesk. Sources: GSI Creos Mr. Color, Gundam Color UG and HUG pages (Japanese, our translation); Tamiya X-20A page. Read Oct 24.

Desk note: At Gundam Planet on Oct 24, one $3.95 Mr. Color or Gundam Color bottle plus the $10.00 250 ml Mr. Color Thinner came to $13.95. The thinner costs more than two bottles of paint, and the 1:1 brush guide means you use it from the first kit.

Gundam Color has fan detail in it. The UG26-29 bottles are Nu Gundam and Hi-Nu Gundam colors, and GSI Creos made three main colors because Hi-Nu's color differs by medium (our translation).

Step-by-Step: hand painting a Gunpla part

1. Choose one family and stay in it. GSI Creos says Mr. Color cannot be mixed with model paints other than Mr. Color and Mr. Color GX. UG and HUG Gundam Colors cannot be mixed with each other.

2. Ventilate for solvent paint. Mr. Color "contains organic solvent", the maker warns; ventilate well during and after use (our translation).

3. Thin before you brush. The Gundam Color page gives paint 1 : thinner 1 for brushing. The general Mr. Color page says add thinner only if it is hard to spread, up to about 1:1.

An overloaded brush of thick white gesso: the opposite of a thinned coat. Photo: Stickpen / Wikimedia Commons, public domain.

4. Slow the drying if you see brush marks. A few drops of Mr. Retarder Mild slow Mr. Color's drying and reduce brush marks, GSI Creos says.

5. Paint thin coats. The maker's airbrush advice is a light first pass, then thin coats on the second and third. Brushing follows the same idea; a r/Gunpla reply below says so too.

6. Pick the sheen. Mr. Color's C30 Flat Base adjusts gloss: 5 to 10% of the paint for semi-gloss, 10 to 20% for matte.

7. Clean the brush in the same thinner. Mr. Color thinner also cleans brushes used with Mr. Color; Tamiya's X-20A cleans tools used with its acrylics.

Diagram: PlamoDesk. Sources: GSI Creos Mr. Color and Gundam Color pages (Japanese, our translation).

GODEEPER: Small details without opening a bottle. Gundam Marker types →

Tips: hand painting Gunpla with fewer mistakes

• Start water-based. GSI Creos aims the HUG line at first-time painters, and it thins with water.
• Do not judge by the bottle. Mr. Color is more viscous than water-based paint, its maker says. That is why its brush guide adds thinner.
• Paint over a surfacer when the color must cover. Our Gunpla surfacer guide covers which gray to use.
• Buy the matching thinner once. It thins and cleans, so it outlasts several bottles.
• Leveling thinner is for the airbrush. GSI Creos designs Mr. Leveling Thinner for airbrush work, and it thins only Mr. Color and Mr. Metal Color.

Diagram: PlamoDesk. Sources: Gundam Planet and USA Gundam Store listings, Oct 24.

What builders say

Two r/Gunpla replies from this month, read through Arctic Shift. Voices, not sources for the facts above.

"Acrylic is the most common so it's fine for detail painting if you are comfortable with a brush. Enamels are also good for small details because you can clean up any mistakes with lighterfluid/mineral spirits/enamel thinner." u/Lyndonli on r/Gunpla, October 2026

"if it's done with paint and brush you need to thin more and do thinner coats of paint." u/Winterspawn1 on r/Gunpla, October 2026

The second reply lines up with the maker's ratio. Thin paint, more coats.

GODEEPER: Seal the paint before decals or grime. Best Gunpla top coat for beginners →

What we don't know yet: GSI Creos says Mr. Color dries fast but gives no time in minutes on the pages we read, and we read no dilution ratio for Tamiya Acrylic. Wait until each coat is dry to the touch.

Our take

Start hand painting with water-based Gundam Color and water; switch to Mr. Color only with ventilation. The HUG line is the one GSI Creos aims at first-time painters, and it skips the $10.00 thinner. Mr. Color dries fast to a hard film, but its maker warns about organic solvent and gives a 1:1 thinning guide you will need from day one. We recheck these prices with the next tools update.

How we checked this

On Oct 24, 2026 we read GSI Creos's Japanese pages for Mr. Color, Gundam Color (UG), water-based Gundam Color (HUG) and Mr. Leveling Thinner, Tamiya's X-20A page, and US listings at Gundam Planet and USA Gundam Store. A research assistant gathered the pages; we re-read the three paint pages and Gundam Planet's prices. Bandai's site was in maintenance. We did not test these paints.

Frequently Asked Questions

What paint is best for hand painting Gunpla? For a first try, GSI Creos's water-based Gundam Color (HUG01-09). The maker says it keeps the Gundam Color hues with less solvent and a milder smell, which makes it ideal for first-time painters. It costs 253 yen with tax in Japan and thins with water.

What is the thinner ratio for brush painting Gundam Color? Paint 1 to thinner 1, per GSI Creos's Gundam Color page; the airbrush guide is 1 to 2. For Mr. Color in general the maker gives paint 1 to thinner up to about 1 for brushing, adding thinner only if the paint is hard to spread.

How do I avoid brush marks on Gunpla? Thin the paint and slow its drying. GSI Creos says a few drops of Mr. Retarder Mild slow Mr. Color's drying and reduce brush marks. Paint in thin coats rather than one thick one, as a r/Gunpla reply also advises for brush work.

Can I mix Gundam Color with Tamiya acrylic? No. GSI Creos says Mr. Color cannot be mixed with model paints other than Mr. Color and Mr. Color GX, and that the solvent UG and water-based HUG Gundam Colors cannot be mixed with each other either. Keep one family per mix.

Do I need ventilation to hand paint Gunpla? With Mr. Color and UG Gundam Color, yes. GSI Creos says Mr. Color contains organic solvent and to ventilate well during and after use. The water-based HUG line has less solvent and a milder smell, according to its maker.

How much does Gunpla paint cost in the US? About $4 a bottle. On Oct 24, 2026 Gundam Planet listed Mr. Color and Mr. Gundam Color at $3.95, Tamiya Acrylic at $4.00, and Mr. Color Thinner 250 ml at $10.00. USA Gundam Store had Gundam Color from $3.50 when we rechecked on Oct 25.

Related Reading

• Gunpla Weathering for Beginners: the step after base colors.
• How to Panel Line Gunpla: lines over a painted part.
• Gunpla Tools Guide: every tool from the first nipper to the finish.
• Gunpla Water Decals: markings on top of paint.
• Gunpla Airbrush for Beginners: the same paints through an airbrush.
• Gunpla Seam Line Removal: closing seams before the first coat of paint.

References

• GSI Creos Mr. Hobby (Japanese): Mr. Color, Gundam Color UG01-29, Water-based Gundam Color HUG01-09, Mr. Leveling Thinner
• Tamiya: X-20A Acrylic Thinner 81020
• Gundam Planet: Mr. Color, Mr. Gundam Color, Tamiya Acrylic, Mr. Color Thinner 250 ml
• USA Gundam Store: Gundam Color 10 ml