Repairing a Surfboard
When choosing a surfboard repair kit the most important thing is to get the same type of resin that your board was originally built with. Modern surfboard blanks are made from two types of foam, polyurethane and polystyrene. Custom boards are made out of polyurethane foam blanks using polyester resin while Epoxy boards like those from NSP, Take Off, Circle One and Cortez must be repaired using an epoxy resin, failing to do so will most likely increase damage. So, don't repair epoxy boards with polyester resin!
Knowing how your board was originally built will make repairing it that little easier! After a foam blank is shaped it is laminated. The laminating process combines both resin and fiberglass cloth to seal the foam and create strength. Most modern surfboards are laminated with 4 and 6 ounce fiberglass cloth using polyester or epoxy resin.
First, the cloth is cut to size and laid over the foam. Then, resin is applied with a squeegee to evenly distribute and saturate the resin in the cloth. The process should be repeated on the bottom carefully wrapping the rails to blend over each other. This is standard procedure for both polyester and epoxy surfboards.
Once the board is laminated and the fin plug are put in, it's time for finishing. Finishing refers to how thesurface of the board looks. There are two basic finishes, sanded and gloss, both begin with a final coat of resin for finish sanding. Polyester boards require sanding resin, which contains a liquid wax additive and coats the surface for easy sanding (note: laminating resin should never be used for finishing - the surface will remain tacky). Epoxy resin is used for both laminating and finishing. The final coat of resin needs to be sanded - usually with a foam backed sanding wheel and a medium grit sandpaper. This step evens the surface of the board. A sanded gloss coat is the base for either a sanded or polish finish. Sanded finishes are then wet sanded with a fine grit and sprayed with lacquer. Gloss finishes require additional wet sanding and polishing.
There are two basic types of minor dings, punctures and fractures. These dings may occur on your board’s nose, tail, rail, or flat surfaces. Small punctures can easily be repaired with Sun Cure™ fiberfill resin or Ding All® Quik Stik™ epoxy putty or with regular polyester resin by following these easy steps:
Resin and hardener, fiberglass, masking tape, sandpaper, cover sheet, mixing cups, mixing sticks, and plastic gloves.
- Dry and clean fracture, light sand the area about 1/4” around the fracture. Cut or grind away any broken fibers to create a void to be filled. For larger fractures requiring cloth laminations, size and cut cloth before mixing resin.
- For taping flat surface and rail dings, tape around the sanded area to prevent resin form spreading. Nose and tail dings require taping under one side to mate the shape of the missing piece – multiple pieces of tape might be needed. Although the resin mixture will be thick, the tape will hold the resin in place around the broken or fractured part and will act as a mold eliminating extensive sanding and shaping.
- For mixing, first estimate the amount of resin needed to fill the ding. Use scissors and chop thin pieces of cloth, (about 1/8” pieces) and add to the resin. The cloth will make the resin very workable and will provide needed strength. Using an adequate mixing cup, estimate resin and add hardener. Once mixed, slowly stir the chopped cloth into the resin (don’t add too much).
- To apply resin on flat surfaces and rail dings, use a mixing stick and work out any air bubbles. A plastic or wax paper cover sheet is applied over the surface of the repair to mold a smooth surface. On rail dings, tape down each end of the cover sheet to hold it in place. Do not remove the cover sheet until the resin has completely hardened. Check the hardening progress by looking at the leftover resin in your mixing cup. Once dry, slowly peel off the cover sheet. If sanding is needed, start by using a medium grit sandpaper. Keep the sanding surface flat and avoid excessive, uneven sanding. Following initial sanding, use fine (wet/dry) sandpaper. To match a gloss finish, polish the repair after wet sanding.
Delamination is when fiberglass cloth becomes separated from the foam on your board and occurs mainly where your feet apply pressure to the board’s surface.
Detected by soft, hollow sections, delamination will quickly crack and absorb water causing the foam in your board to discolor and rot if left alone. Delamination can easily be repaired by following these steps:
- Gather your materials and tools: resin and hardener, drill with 1/8” bit, wax paper, weight (slightly larger than repair area) and a Ding All® Delamination Repair Bottle.
- Prepare your board. Remove all wax and dirt. Drill two holes at opposite ends of the repair. Squeeze all of the moisture out of the repair and lay the board flat.
- Mix: Estimate enough resin to fill less than half of the delamination. Pour the resin into the bottle, add hardener, replace cap and shake.
- Apply the resin by squeezing into each hole leaving room for compression. Place wax paper over the top of the repair and add weight to flatten.
- Once dry, remove the weight and wax paper. If resin leaked out, sand the area.
Using Sun Cure™ fiberfill resin:
- Remove all moisture, loose particles and dirt from the repair area.
- Rough sand the surrounding area to allow resin a secure bond.
- In the shade, apply the needed amount of Sun Cure™ to the repair with an application stick. Make sure to work out any air bubbles and form the resin to the repair.
- For flat surface or rail dings apply the clear plastic cover sheet over the resin to mold the surface and create a no-sand finish. (Note: Make sure to take each side of the cover sheet to hold in place.)
- Expose the repair to sunlight (If you can see a shadow, Sun Cure™ will work).
- Bright Sun: Gel 15 seconds – Full cure 4 to 6 minutes
- Partial Sun: Gel 25 seconds – Full cure 6 to 8 minutes
- Light Overcast: Gel 45 seconds – Full cure 12 to 20 minutes
- (Note: when using Sun Cure™ in intense summer sun, thick repairs may need to be taken in and out of the sun every minute to avoid excessive heat build-up to avoid cracking.)
- Make sure resin has completely hardened before removing the plastic coversheet or sanding. Sun Cure™ has a tack-free surface that will allow an easy sand finish.
Using Q-CELL filler
When added to polyester or epoxy resin, Q-CELL filler thickens the resin to make it more workable and expands it to fill in large areas. This expansion reduces the amount of resin required therefore reducing weight. (Note: Q-CELL is only a filler and should be sealed with a coat of resin before use). The following lists instructions for using Q-CELL filler:
- Estimate needed resin and mix in hardener.
- Add Q-CELL to resin in small amounts until desired consistency is reached. (For best results, a medium paste is recommended, avoid adding too much Q-CELL to the resin mixture or it will be too thick to apply.)
- Stir resin until Q-CELL is completely saturated.
- Apply mixture to the repair.