
Originally Posted by
LBCrew
First, be sure your blank is polyurethane if you bought polyester Ding All resin. If you bought epoxy Ding All, you can use it no matter what. Usually, but not always, epoxy resin is used to glass over polystyrene (EPS) foam. If so, you MUST use epoxy resin. You can use polyester resin to repair an epoxy or polyester lamination, but only if the core material is polyurethane, and NOT polystyrene. You can tell polyurethane foam from polystyrene foam by looking at it closely... polyester foam will be crispy and crumbly; polystyrene will be little beads (EPS) or tough and kind of rubbery (XPS).
Put your board on the rack bottom up, and level the damaged area. Remove any loose fiberglass and sand. Tape off the deckside slice with masking tape, wrapping the tape around the tail rail and ending at the bottom edge of the rail. This prevents the resin from running through the slice and dripping out the other side. Mix your resin and hardener and some filler material... either q-cell or microballoons or cabisil... to make a thick paste that barely flows, and pour it into the slice to fill up the gap to the level of the flat bottom. Don't use too much or too little. Just fill the slice level with the bottom of the board. Let it cure. Remove the tape, sand the area around the slice, and laminate a patch over the bottom side slice that wraps around the rail to the deck side. Let cure; fair the edges of the patch. Flip the board and do the same to the deck side, wrapping the patch around to the bottom. Let cure; fair the edges of the patch. Tape off the bottom edge of the board, deck side up, so the tape hangs off the edge and forms a drip edge. Paint a hotcoat over the patch; let cure. Flip. Do the same to the bottom, taping off a drip edge, and painting a hotcoat over the patch. Sand smooth. Done.