Solarez Epoxy Resin with Microlite. It is a white putty made of high-strength UV-Cure resin and super lightweight additives that effectively repair ALL TYPES OF SURFBOARD FOAM, including Styrofoam. This putty cures in roughly 3 minutes by exposure to sunlight or artificial UV light. It sands and fairs very nicely, making it an easy one-step repair for almost any ding. UV-CURE (for superficial dings less than 1/4″ deep).
Apply in the shade.
For easier shaping and faster curing, cover the wet resin with a sheet of clear plastic wrap (Mylar is best).
You can easily shape the resin to the contour of the board.
Expose to sunlight for 3 minutes
Peel off plastic wrap and touch-up sand.
