I surfed a shallow northern reefie last night trying to escape that howling onshore. Anyway the reef was a bit closer to the surface than I thought, so I ended up looking for lobsters once or twice.

The glass fins took a bit of a blow, and have all started to split and fray on the leading edge.

Is this something that can be sanded back and glassed/painted over? At $160 a pop for the JW fins I'd rather not fork out for another set...

I think windsurfers fix their fins that are chipped (and then hum and are super annoying) by using some sort of resin then sanding them back. I've used epoxy resin on my fibreglass fins and done this and it seems to work. Don't know if it is the right way to do it though.

I have fixed fins that have received the same damage you are describing, both foam core and carbon fcs fins, with just a little 4oz cloth and resin. I have also used marine epoxy putty www.bunnings.com.au/pc-products-57g-pc-marine-epoxy-putty_p1560095 , that stuff is gold. =)

Small chips can be sanded out, start with 180dry and finish with 400 wet and dry.

Bigger chips can be filled with resin.

One trick I found was to lie the fin on a flat piece of glass (flat side down) and put the resin over the chip. Less sanding if you do it like that.

Ive saved a few sets of fins this way