Same tried & proven formula for over 20 years has saved many a surfboard from the perils of water induction in countries all over the Globe. Simple to use: sand-prep (60 grit) the surface around the ding, squeeze out enough Solarez to fill the ding, cover the wet resin with a piece of plastic baggie, smooth it out, and EXPOSE TO SUNLIGHT FOR A MINUTE OR TWO. Now, peel off the baggie and do some minor touch-up sanding with the 240 grit side and GO SURF!
This is a LOW EXOTHERM formula that will not melt delicate EPS like other products. They don't melt at first, but while curing, the exotherm so much, they melt the foam and actually create a more cavernous ding than you had!
Solarez has glass and ceramic fibers in it which provides better adhesion, and impact resistance. That, coupled with a flexible resin gives Solarez Epoxy Ding Repair a tough, resilient finish. - IN LESS THAN THREE MINUTES