Gelcoat is an unsaturated special polyester resin, colored in different shades or transparent, for painting and protecting the outer surface of polyester constructions produced mainly through a mold. It is applied (painted) to the mold - after special release agents precede - and before the coating of the glass fabric and the resin. The surface of the Gelcoat in contact with the mold hardens completely, while the other side (outside) remains slightly tacky. This property is very important because it allows the polyester resin that is passed over the Gelcoat to stick perfectly with it. In the event that a polyester object (eg boat, car part, tank, etc.) has paint damage and needs to be repaired externally, the most appropriate product to have perfect adhesion on an older gelcoat is to reuse gelcoat. By adding paraffin inside the cured Gelcoat, but only on the outter layer, the surface is completely sealed and the paint dries completely, leaving no traces.