How to Paint an RC Car Body with Liquid Mask: Step-by-Step Guide

Liquid mask lets you paint RC bodies faster with cleaner lines than masking tape. Here's how it works: brush on 2–3 coats of peelable mask, sketch your design, cut the pattern with a hobby knife, then spray your colors from darkest to lightest. Finish with a white or black backing coat to lock everything in.

We'll walk you through each step, the tools that make the job easier, and the products our team uses on race bodies.

Tools You'll Need

If you're tired of tape bleed and want to try something faster, here's what you need.

Complete toolkit:

• Liquid mask (BittyDesign 16oz or Tamiya Masking Fluid 20ml) – one bottle covers 3–4 touring shells
• Hobby knife with #11 blade – replace blade every 2–3 bodies for clean cuts
• Wide soft brush (1–2 inches) – smooth, even coats without streaks
• Spray paints like Tamiya PS-1 White, PS-5 Black, or Spaz Stix for airbrush
• White or black backing paint – locks color and prevents transparency
• Mild dish soap and soft sponge – removes oils and mold-release agents
• Cutting mat (optional) – protects work surface and gives you a clean cutting area

If you prefer airbrushing, read our Complete RC Airbrush Guide for Car Body Paint.

Step 1: Wash the Shell

Clean Lexan shells need detergent washing: scrub the inside, rinse fully, then dry completely so mask and paint adhere properly.

Use a clean, soft sponge and a small amount of dish soap to wash the inner surface of the polycarbonate body. This step removes oils, dust, and mold-release agents that prevent adhesion. Wash and rinse the body carefully. Leave it to dry completely. Water droplets under the mask will cause lifting and paint defects.

Step 2: Apply Liquid Mask (2–3 Coats)

Once your shell is spotless and dry, you're ready to apply the masking fluid.

Brush on 2–3 thin coats and let each dry 20–30 minutes so the mask doesn't foam or lift at the edges.

Grab a wide brush (1–2 inches works best) and apply the masking fluid to the inside of the Lexan. Work in smooth strokes and don't overwork corners or curves, or you'll create foam bubbles. Need to speed things up? Use warm air from a hairdryer on low, and you can cut drying to 10–15 minutes per layer.

You'll notice the mask almost disappears once it's dry. That's normal. It's still there.

Quick tip: Thin coats are your friend. One thick layer tears when you cut it; two thin layers peel cleanly. For most 1/10 touring shells, 2 coats do the job. If you're painting a 1/8 buggy body with tight curves, add a 3rd coat on those corners. Let the final coat cure at least 1 hour before cutting.

Step 3: Sketch the Pattern

With your mask cured and invisible, it's time to plan your design.

Draw your design on the protective outer film so you can see cut lines without marking the Lexan.

Sketch the desired pattern on the protective plastic on the outer surface of the body. Not all bodies have a removable film, so check this before you start sketching. If there's no film, sketch lightly with a washable marker on the outside. When you're working on your first body and learning the painting process, go for larger and simpler designs. Two or three colors with basic stripes or blocks work great. Once you master those, try flames, fades, or multi-layer graphics.

Not sure which body size you have? Check our body size guide.

Step 4: Cut the Mask

Now comes the satisfying part: cutting your artwork into the mask.

Use a sharp #11 hobby knife and score lightly in one smooth pass—pressing too hard leaves cut marks on the finished body.

Press the knife as gently as possible and avoid "sawing" back and forth. This lifts edges and causes fuzzy lines. Peel away the cut sections slowly at a 45° angle.

At this point, don't rush. A dull blade will ruin hours of work.

Step 5: Paint Dark-to-Light, Then Back

With your mask sections removed, you're ready to spray. This is where your design comes to life.

Always start with the darkest color first to prevent bleed-through, then work toward lighter colors and finish with a white or black backing coat.

Start by removing the masking from the area where the darkest color will be applied. After peeling away the mask, paint the area with spray paint or airbrush. Once you've applied your coats (let each coat flash 5–10 minutes), you can move on to trim the next pattern. You can cut all the patterns of the same color at once. With lighter colors like yellow, pink, or light blue, you may need 3–4 coats to get full coverage and saturation.

Not sure which paint to use? Our Tamiya Spray Paint Guide covers color codes and application tips for Lexan bodies.

Remove mask from the areas you want to paint:

Proceed to next color:

After darkest areas are painted, remove the rest of the mask from lighter areas:

Step 6: Apply the Backing Coat

Pick white or black backing paint depending on your color scheme: white backs light colors; black backs dark colors to lock saturation.

Once all your design colors have dried, apply the base backing paint, either white or black. As a general rle: if you used mainly dark colors like red, purple, or dark blue, pick black backing to add depth and contrast. If you used lighter colors like yellow, pink, orange, or white details, pick white backing to keep them bright and saturated (the ones that look washed out without backing).

Apply 2–3 heavy coats of backing paint to fully cover the design layer and prevent transparency. Let the backing coat cure for 24 hours before handling the body or cutting window masks.

There's nothing like peeling back that final mask layer and seeing your design come to life. Worth every minute of prep.

Used white base color since front of the body is also white:

Once the backing paint has dried fully, cut out the window masks with scissors or a knife, then trim the body shell to the desired shape following the trim lines. Finally, remove the protective plastic film where you sketched the pattern.

Liquid Mask vs Masking Tape: Pros and Cons

Liquid masking evolved as a faster alternative to tape for RC painters who needed complex designs without bleed-through. Instead of cutting dozens of tape pieces for flames or fades, you brush on a peelable coating, cut your design, and paint. The method took off in touring car racing where multi-color schemes became standard (we've used it on our team cars for years, and once you get the hang of it, you won't go back to tape for intricate work).

Here's how liquid mask and tape stack up for RC body painting:

Feature	Liquid Mask	Masking Tape
Time for complex designs	30–50% faster on flames, fades	Slower; requires precise cutting
Bleed-through risk	Lower with proper application	Higher on curves and corners
Curve control	Excellent; cut any shape	Limited; tape doesn't flex smoothly
Ease of removal	Peels cleanly after paint cures	Can lift paint if removed too soon
Best for	Multi-color, tight curves	Simple blocks, straight lines

Safety Essentials for Painting

Polycarbonate paints smell strong because they contain harsh solvents. Wear a vapor respirator (not a dust mask) and work in a ventilated area.

Use a vapor respirator rated for organic solvents (look for cartridges marked "OV" or "A1"). Open garage doors or use an exhaust fan to move fumes out, and avoid painting near open flames or pilot lights. Solvent vapors are flammable.

We learned this the hard way after a team member got lightheaded in a closed garage. Don't skip the respirator.

Safety checklist:

• Vapor respirator (not a dust mask)
• Ventilation (open doors, exhaust fan)
• Eye protection (safety glasses or goggles)
• Gloves (nitrile or latex)
• No open flames within 10 feet

For more pro tips on safe painting, read Team Driver tips: How to paint without masks.

Troubleshooting Common Mistakes When Using Liquid Mask

Even experienced painters run into these issues. Here's how to fix them fast.

Paint bleeds under the mask

Apply a 3rd coat in problem areas and let it cure fully as described in Step 2. Score edges lightly with a fresh blade. If bleed happens after painting, re-mask the area with a thin coat, let it cure, then spray a touch-up layer. For major bleed (1/4 inch or more), strip the section with isopropyl alcohol on a cotton swab, re-mask, and repaint. Avoid acetone or harsh solvents; they can crack Lexan.

Mask lifts when cutting

Replace your blade if it's dull (every 2–3 bodies as noted in the tool list). Score lightly in one smooth pass as shown in Step 4. Let the mask cure fully before cutting.

Fuzzy edges after peeling

Let paint cure 30+ minutes, use warm air to speed drying, and peel slowly at a 45° angle. If edges are still fuzzy, lightly sand with 1000-grit sandpaper and reapply a thin coat of that color.

Foaming or bubbling during application

Use thinner coats as described in Step 2. Let each dry properly and avoid overworking wet areas with your brush. "Foaming" happens when you brush too aggressively over partially dried mask.

How to Use Liquid Mask on RC Body FAQs

Can beginners use liquid mask on RC cars?

Yes. Start with simple designs: 2–3 colors with stripes or blocks. Liquid mask is more forgiving than tape for first-time painters because it peels cleanly and doesn't leave adhesive residue. You'll master the technique in one body.

Does liquid mask leave residue on RC bodies?

No residue appears when you apply 2–3 coats and let each cure 20–30 minutes. If you see residue (rare), wipe with a damp cloth. Avoid acetone or harsh solvents that damage Lexan. BittyDesign and Tamiya masking fluids are formulated to leave zero residue on polycarbonate.

Can you use liquid mask with multiple paint layers?

Yes. Spray your first color, let it cure 30+ minutes, re-mask over the painted area, cut the new design, then spray the next color. Always paint dark-to-light. Some advanced painters use 4–5 color layers with masking fluid for complex fades and gradients.

Can you reuse an RC body after liquid mask painting?

Yes. Strip old paint with isopropyl alcohol (70–90%) or a dedicated Lexan paint remover, wash with mild soap, dry fully, and re-mask. Avoid acetone, lacquer thinner, or harsh solvents that crack polycarbonate. Most 1/10 touring bodies can be repainted 4–5 times before the Lexan gets too thin or scratched.

Start Your Next RC Body Paint Project

Liquid mask painting delivers professional results once you master the 6-step process: wash, mask, sketch, cut, paint dark-to-light, then back. Your first body takes 2–3 hours, but you'll cut that time in half by your third shell. The technique works on any polycarbonate body from 1/12 pan cars to 1/8 buggies.

Pick up BittyDesign Liquid Mask 16oz and Tamiya PS spray paints from our painting accessories collection. Grab a sharp hobby knife, a wide brush, and you're ready to paint. Need help choosing colors or tools? Contact our team at info@eurorc.com as we've painted hundreds of race bodies and can point you to exactly what you need.

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