Catch waves with 20% off!

A Simple Guide to Fixing Your Broken Surfboard

1/16/20265 min read

How to Fix a Surfboard Ding: A Beginner's Guide

Before you start

Most small dings, coin-sized or smaller on the deck or bottom, make an easy first repair. Expect about 1–2 hours of work plus curing time. A ding is any crack, chip or hole in the hard outer shell (the fibreglass and resin). Fix it quickly: if water gets into the foam inside, it turns yellow-brown, gets heavy and slowly rots.

Good first dings to try:

Small pressure cracks or chips on the deck or bottom
Rail dings where the foam underneath is still solid
Dings smaller than a 50c coin

Stay safe:

Work outside or somewhere with lots of airflow. Resin fumes are strong.
Wear nitrile gloves. Resin irritates skin and is hard to wash off.
Wear safety glasses when you sand or grind.
Wear a dust mask (P2 or better) when sanding, because fibreglass dust itches and is bad to breathe in. A respirator with organic vapour cartridges is best when working with polyester resin.
Keep resin away from kids and pets, and don't eat or drink while you work.

Step zero: is your board polyester or epoxy?

This is the most important check. Polyester resin melts the foam inside an epoxy board, so using the wrong resin can wreck it. If you're not sure, use epoxy resin. It's safe on both kinds of board.

Polyester (PU) board:

Fine, even white foam inside the ding
Heavier, with a dull knock
Sticker often says "PU"
Most traditional handmade shortboards and longboards
Use polyester or epoxy resin

Epoxy (EPS) board:

Foam made of little round beads, like a foam esky
Lighter, with a hollow knock
Sticker often says "Epoxy" or "EPS"
Many pop-out, softer-looking or "tech" boards
Use epoxy resin only

Still not sure? Search the brand and model online, or ask at a surf shop.

Tools needed

You can get all of these at a hardware store for roughly $40–60, and you'll reuse them on every repair.

Utility knife (Stanley knife): cuts away cracked, loose fibreglass
Sanding block: keeps sanding flat so you don't dig hollows
Sandpaper (80, 120, 240 and 400 grit): coarse for prep, finer for a smooth finish
Masking tape: masks off the area and builds a "dam" to hold resin on rails
Plastic mixing cups and paddle-pop sticks: for mixing resin
Plastic spreader or old credit card: spreads resin flat
Scissors: cut fibreglass cloth
Wax comb and scraper: get wax off around the ding
Nitrile gloves, safety glasses, P2 dust mask: for safety
Rags: for cleaning up

Materials needed

For your first repair, buy a pre-packed ding repair kit from a surf shop. The resin and filler are already matched, and the instructions are for that brand. Choose an epoxy kit if you're unsure what your board is made of.

Solar-cure (UV) resin: for small dings. It sets in a few minutes in sunlight and needs no mixing, which makes it the easiest option for beginners. Check that it's epoxy-safe if your board is epoxy.
Two-part laminating resin and hardener: for bigger dings. It sets over a few hours. Mix exactly to the ratio on the label.
Fibreglass cloth (4–6 oz): rebuilds strength over dings bigger than a fingernail. Cut it 1–2 cm bigger than the ding on every side.
Filler (Q-cell or micro-balloons): mixed into resin to fill deep holes. It makes a paste that sands easily.
Acetone or denatured alcohol: cleans the area before the resin goes on, and cleans your tools.
Replacement foam (optional): fills big chunks of missing foam.

Step-by-step repair

If you're using solar-cure resin, work in the shade, because sunlight sets it early. Read your kit's own instructions too, as brands differ slightly.

1. Dry the board completely.
Rinse off salt water with fresh water. Stand the board with the ding facing down, out of the sun, so the water drains out. Leave it for 2–7 days, until the foam around the ding looks white and dry rather than brown or damp. Resin won't stick to wet foam, and trapped water keeps rotting it.

2. Remove the wax.
Scrape the wax off 5–10 cm around the ding with a wax comb, then wipe the area with acetone or alcohol.

3. Cut away the loose bits.
Use a utility knife to trim off any cracked, lifting or crushed fibreglass until only solid edges are left. Pick out any damaged or brown foam.

4. Sand the area.
Sand around the ding with 80 grit, about 2 cm past the damage. The shiny surface should turn dull and scratchy so the resin can grip. Wipe off the dust and clean with acetone again.

5. Tape it off.
Put masking tape around the sanded area to keep resin off the rest of the board. On a rail, build a small tape wall so the resin can't run off.

6. Fill the hole (deep dings only).
Mix resin with filler until it's like thick peanut butter. Press it into the hole with a paddle-pop stick and leave it slightly higher than the surface, because you'll sand it flat later. Shallow cracks don't need filler, so go straight to step 7.

7. Add fibreglass cloth (dings bigger than a fingernail).
Cut a patch of cloth 1–2 cm larger than the ding on every side. Lay it over the ding and wet it with resin, spreading from the middle outward until the cloth goes clear. Squeeze out any air bubbles. White spots mean the cloth is dry there, so add a little more resin.

8. Let it cure.
Solar-cure resin needs about 5–15 minutes in direct sun. Two-part resin should be left overnight somewhere warm. It's ready when it's hard and no longer tacky to touch.

9. Sand it smooth.
Remove the tape. Sand with 80 grit on a block to knock down the high spots, then move to 120, 240 and finally 400 grit. Keep the block flat and stop when the patch is level with the board. Don't sand into the good glass around it.

10. Seal and finish (optional but better).
Brush a thin final coat of resin over the patch to waterproof it and make it look smoother. Let it cure, then sand lightly with 400 grit.

11. Check it's watertight.
Press around the patch. There should be no soft spots or cracks. Re-wax and go surfing, though waiting an extra day for a full cure is best.

Common beginner mistakes

Resin still sticky after curing: the mix ratio was wrong, it was too cold, or it didn't get enough sun. Sand off the sticky layer and apply again, measuring carefully.
Foam melted or bubbled: polyester resin was used on an epoxy board. Cut out the damaged foam and refill with epoxy only.
Patch peels off later: the board was wet, or the area wasn't sanded or cleaned. Remove the patch, dry the board fully, then sand, clean and redo it.
Resin set in the cup: solar resin was out in the sun, or the batch of two-part resin was too big. Work in the shade and mix small batches.
Dip or hollow around the patch: it was sanded with fingers instead of a block, or sanded too much. Add a thin coat of resin and sand it flat with a block.
White or cloudy patches: dry cloth or air bubbles. Sand lightly and add another thin coat of resin.

Tip: practise on a junk board first. Tip shops and Marketplace often have wrecks for next to nothing.

When to take it to a pro

Leave these jobs to a repairer until you've done plenty of small dings:

Snapped or creased boards (a crack running across the board)
Broken or ripped-out fin boxes and leash plugs
Large delamination (the fibreglass lifting off the foam in a bubble)
Big areas of waterlogged, brown or soft foam
Expensive or sentimental boards you don't want to risk