Newbie question here - does anyone know what type of board construction this is as i need to do a small repair to the tail. Worried about using wrong filler/resin and melting it. Is there an easy way to tell? The ding has already been made watertight by the previous owner with a clear glue/resin. The board feels superlight (4.7kg) and is 7'6 in length with no writing on it at all.