How to Fix Paint Defects in Scale Model Cars

Alpha Model Tech Share Series · 2026 · All Scales
Paint defects are among the most common frustrations in model building. The good news is — most of them can be fixed. Here are solutions for the most common paint issues.

01 · Orange Peel

Appearance: bumpy, textured surface resembling an orange peel.
Cause: spraying too far away, applying too thick coats, high air pressure, or fast-evaporating thinner.

Solution:

• Sand gently with 2000–3000 grit sandpaper using a GodHand sanding block (GH-KS10).
• Polish with compound and finish with a clear coat for protection.
• When respraying: keep an 8–13cm distance, apply thin coats, and control air pressure.

02 · Runs & Sags

Appearance: paint drips or sags forming tears or streaks.
Cause: applying too much paint at once, moving the airbrush too slowly, or pausing on edges.

Solution:

• If wet: blot up excess paint with a brush or absorbent paper.
• If dry: sand smooth with the GodHand block and respray.
• Edge technique: flick your wrist quickly at sharp edges — never pause there.
• Prevention: thin coats, 5-minute intervals between coats, 2–3 coats total, never spray heavy in one pass.

03 · Paint Build-Up & Pooling in Recesses

Appearance: excessive paint accumulates in grooves and corners with uneven thickness.
Cause: improper spray angle causes paint to flow and pool in low areas.

Solution:

• Use the GodHand sanding block to carefully flatten overbuilt areas.
• Cross-coat method: first pass horizontal, second pass vertical to avoid dead spots.
• Maintain consistent speed — start moving before pulling the trigger, release after finishing the pass.

04 · Dust & Particles

Appearance: dust or fibers embedded in the paint surface.
Cause: unclean spraying environment or dusty workbench.

Solution:

• Small particles: once dry, sand lightly with 2000 grit, polish and clear coat.
• Large particles: sand down to base and respray the entire panel.
• Prevention: clean the body with a tack cloth before spraying, strain paint through a filter.

05 · Uneven Coverage

Appearance: base color showing through or uneven color distribution.
Cause: not enough coats, dirty primer, incorrect thinner ratio.

Solution:

• Ensure the primer coat is flat, clean, and free of oil.
• Apply more coats, keeping each one thin.
• Check the thinner ratio (typically paint:thinner = 1:1 to 1:2).
• Some colors like yellow and red need more coats for full coverage.

06 · Blistering

Appearance: small bubbles or blister-like bumps appearing on the paint surface.
Cause: paint drying too fast, primer not fully cured, or moisture intrusion.

Solution:

• Sand off the blistered area.
• Confirm the base is completely dry before respraying.
• When humidity > 70%: use retarder thinner to prevent blushing.
• When temperature < 15°C: increase the thinner ratio, use fast-dry thinner.
• Check if the paint is expired or degraded.

07 · Metallic Flaking / Flotation

Appearance: metallic flakes distributed unevenly, looking cloudy or whitish.
Cause: unstable spray pressure, wrong thinner type, or spraying too close.

Solution:

• Minor issues can be fixed with polishing.
• Severe cases require sanding and respraying.
• Use dedicated metallic paint thinner, maintain steady pressure and an 8–13cm distance.
• Never touch up metallic paint with a brush.

08 · About Paint Stripper

If you need to start over, simply soak the part in Yoshikawa paint stripper.

• After soaking, filter with filter paper and save the stripper for reuse.
• Paint stripper can be reused — no need to replace it frequently.
• To redo a single panel: strip the entire panel down to bare plastic, never spot-repair panel by panel.

09 · About Drying Time

After spraying, allow at least 24 hours of drying time at room temperature before applying the clear coat. Applying the clear coat too soon will cause bubbling and cracking.

10 · Recommended Tools

11 · Spraying Golden Rules

1. Distance: keep the airbrush 8–13cm from the workpiece.
2. Movement: consistent speed — start moving BEFORE pulling the trigger, release AFTER finishing the pass.
3. Coats: 5-minute intervals, 2–3 thin coats only.
4. Pattern: cross-coat method (horizontal, then vertical).
5. Edges: quick wrist flick at sharp corners, never pause.
6. Drying: wait a minimum of 24 hours before clear coat.

Build. Detail. Inspire. — Alpha Model Technical Team