How to Sand Resin Projects for a Glossy Finish (240, 400, 800, 1500 Grit Step-by-Step Guide)

Resin is a popular material for art, crafts, jewelry, and countertops because of its glass-like finish and durability. However, once cured, resin surfaces often have imperfections such as uneven spots, bubbles, or dull patches. The best way to achieve a crystal-clear, glossy surface is by sanding with a progression of grits. This guide shows you how to sand resin projects properly using 240, 400, 800, and 1500 grit sandpaper.

Why Sanding Resin Matters

Even perfectly poured resin pieces can have minor flaws. Sanding evens out these areas, removes surface haze, and prepares the resin for polishing or finishing.

Benefits of sanding resin include:

• Leveling: Smooths out uneven cured layers or edges.
• Clarity: Removes surface scratches and cloudiness.
• Polish-ready: Prepares resin for a mirror-like shine.
• Professional results: Makes handmade projects look flawless and durable.

Understanding the Grits

• 240 grit: Removes rough edges, drips, or uneven cured spots.
• 400 grit: Smooths scratches left by 240 grit and begins refining the surface.
• 800 grit: Creates a semi-smooth finish that’s ready for fine sanding.
• 1500 grit: Delivers a polished, glass-like surface before buffing.

Tools and Supplies

• Wet/dry sandpaper sheets: Prevent overheating and clogging while sanding resin.
• Sanding block: Keeps even pressure across flat resin pieces.
• Water and spray bottle: Essential for wet sanding to reduce friction.
• Polishing compound: For the final shine after sanding.
• Soft cloth or buffer: Used for polishing and removing residue.

Step-by-Step Guide

1. Start with 240 grit. Use 240 grit (25-pack) to remove uneven cured resin, drips, or surface defects. Always wet sand to prevent melting.
2. Move to 400 grit. Apply 400 grit (100-pack) to refine the surface and smooth scratches left by 240 grit.
3. Sand with 800 grit. Switch to 800 grit (25-pack) for further refinement. The resin will look more even and slightly clearer.
4. Finish with 1500 grit. Use 1500 grit (50-pack) to achieve a near-polished finish. Wet sanding here is essential for clarity.

Special Considerations

Thick resin layers: May require longer time with 240 grit to flatten.

Colored resin: Sand carefully to avoid dulling pigments; always polish afterward.

Jewelry pieces: Use small sanding pads or cut sheets for better control.

Pro Tips

• Wet sand at every stage to reduce heat and dust.
• Sand in one direction for each grit, alternating directions between grits for better results.
• Replace paper as soon as it clogs to maintain consistency.
• Finish with a resin polishing compound for maximum clarity.
• Be patient—resin takes time to sand properly.

Aftercare

• Polish resin pieces with a buffing compound after 1500 grit sanding.
• Wipe with a microfiber cloth to remove residue.
• Seal with a resin topcoat if extra durability is needed.

FAQs

• Can I skip from 240 to 800 grit? Not recommended—skipping grits leaves visible scratches.
• Is dry sanding okay for resin? No—always wet sand to prevent resin from melting.
• What if my resin still looks cloudy? Continue sanding with finer grits and finish with polish.
• Do I need a buffer? Buffers help but aren’t required—manual polishing also works.

Watch & Learn

Shop resin sanding sheets: Get 240, 400, 800, and 1500 grit sandpaper in convenient packs. Shop resin sanding sandpaper.

Closing Thoughts

Sanding resin projects may feel time-consuming, but it’s the key to achieving that crystal-clear, glossy finish that resin is known for. By moving through 240 → 400 → 800 → 1500 grits, you remove imperfections and prepare your project for polishing. With the right grit sequence and patience, your resin crafts will look professional and brilliant.