Sanding or Finishing Reinforced Resin Structures

How Long Should You Wait Before Sanding or Painting?

Before attempting any sanding or painting, always allow your reinforcement resin, fibreglass putty, or repair kit to cure fully. Most formulations are touch-dry within hours but may require up to 24 hours or longer for complete curing, depending on temperature, humidity, and the specific product instructions. Insufficient curing will lead to surface imperfections, poor adhesion of paints, and potential failure of your repair.

• Refer to your resin or putty product guidelines for minimum curing times.
• If in doubt, a cured surface should feel hard, not tacky, and resist gentle pressure without marking.

Sanding Techniques for Reinforced Resin Surfaces

Once cured, begin sanding with a medium to fine grit sandpaper. Sand in gentle circular motions, taking care not to overheat the surface. For large or rough repairs, start with a coarser grit and progress to finer grits for a smoother finish. Always clean dust before moving on to priming or painting.

• Fill deep imperfections with a fibreglass-reinforced product, such as CROP 2K Fiberglass Putty – 750 ml + Hardener, for tougher jobs. It sands down readily after full cure.

Priming and Painting for a Lasting Finish

After sanding, remove all dust and debris for optimal adhesion. Use an appropriate primer for resin or composite surfaces to ensure paint bonds well and achieves a uniform appearance. Only begin painting once the primer has dried to the manufacturer’s recommendation. Using compatible products intended for use with reinforced resins helps preserve your work’s durability and professional look.