I have picked up an old PE board for free to teach my kids to sail, it is in pretty good nick, except for a ding about the size of 5c piece. I have heard that either using a melted plastic milk bottle or 2 pack epoxy are two ways of repair. I'm not worried about looks Any suggestions?
Aqua putty from Bunnings is an easy and stong fix. You just knead with your fingers and apply. Sand and paint or just leave as is to add some character. Roughly $20. Your kids will probably put some more dings in it, so handy to have around and can apply even when wet.