Same tried & proven formula for over 20 years that has saved many a surfboard but is now available in a very low-light curing formula for inclement weather. 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, EXPOSE TO AS MUCH SKYSHINE AS YOU CAN GET - PREFERABLY MID-DAY. Black skies & precipitation means you should probably be in a pub. You can always use the Solarez UV flashlight that cures our fly-tying resins.
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