Can I Sand the Base Coat?

Short answer

Usually not, if an effect paint is going to be applied over the base coat. The base coat before Chameleon, Candy, Pearl or Ghost Pearl should be clean, dry and properly flashed off. We do not recommend normally sanding the base coat before the effect layer, because it can change the colour of the base, damage the metallic or pearl effect and create visible marks in the final result.

Why is the base coat not normally sanded before effect paint?

A base coat is not the same layer as filler primer. Filler primer is used to level the surface and is normally sanded after curing. The base coat, however, creates the optical foundation for the effect paint. Its colour, evenness and structure directly affect the final appearance of the effect.

If you sand the base coat, you may lighten it, scratch it, make it unevenly matte or damage metallic and pearl pigments. These defects can become more visible after applying the effect paint and clear coat.

What happens when sanding a black base?

For Chameleon, Flip-Flop, Pearl, Hologram or Glitter paints, a black base is very important. If it is sanded after application, a deep black surface can become dark grey or uneven.

This can significantly weaken the effect, change the final shade or make the colour shift less intense than it would be on a correctly prepared black base.

What happens when sanding a silver base under Candy?

With Candy paints, the correct silver metallic or pearl base is essential. This is the layer that reflects light back through the transparent Candy colour.

Sanding can damage the metallic or pearl effect, change the orientation of the pigments and create patches, cloudy areas or uneven light reflection. After the Candy paint is applied, these differences can become very visible.

What if there is dust or a defect in the base coat?

If dust gets into the base coat, a run appears or another visible defect occurs, it is usually not ideal to simply sand the base and continue with the effect paint. In most cases, it is better to repair the defect, prepare the surface again and reapply the base coat in that area.

The goal is for the base to be even, clean and uniform in colour before the effect paint is applied.

When can the base be lightly prepared?

If the waiting time between the base coat and the effect paint was too long, the surface may need to be prepared again depending on the material used. With effect paint systems, however, this must be done carefully, because normal sanding can damage the appearance of the base.

If you are not sure, we recommend testing the process on a small area first. On important parts, it is safer to reapply the base coat after preparation than to apply effect paint over a damaged or unevenly sanded base.

What is the correct process?

• allow the filler primer to cure and sand it smooth,
• clean and degrease the surface,
• apply the correct base coat according to the type of effect,
• allow the base coat to flash off properly,
• do not normally sand the base coat before the effect paint,
• apply the effect paint in thin, even coats,
• protect the result with a suitable clear coat.

The difference between sanding filler primer and sanding base coat

Filler primer is sanded to make the surface smooth and ready for the next layers. Base coat is used to create the correct colour and optical foundation. That is why it is treated differently before the effect layer.

Simply put: filler primer is sanded, but base coat before effect paint is usually not.

Summary

• Base coat is not normally sanded before effect paint.
• Sanding can change the colour, damage the base effect or create visible marks.
• With Chameleon and Pearl paints, a sanded black base can become lighter and weaken the effect.
• With Candy paints, sanding can damage the silver metallic or pearl base.
• If there is a defect in the base, it is better to repair it and make the base uniform again.
• Filler primer is sanded, but base coat before the effect layer usually is not.