Use aluminum oxide or silicon carbide sandpaper —they're best suited for fiberglass surfaces. Wet sanding is ideal for a flawless, glossy finish while reducing airborne dust. Use light, consistent pressure to avoid swirl marks or sanding through the gelcoat. This guide explains how to sand fiberglass step by step using 80, 120, 220, and 400 grit sandpaper. Sanding removes imperfections, smooths transitions, and creates texture for primers and paints to adhere. Without. Fiberglass is a type of plastic that is impregnated with small glass fibers for reinforcement (it is also known as GRP, for glass-reinforced plastic). Are you ready to transform your boat sanding skills in just one day? In this comprehensive tutorial, we'll provide you with easy-to-follow tips and techniques to achieve a smooth finish on your boat.
