First, the rule that saves boards
Never put polyester resin on an epoxy board. Polyester resin will eat the EPS foam inside an epoxy board — it dissolves it, leaving a soft crater that's far worse than the original ding.
Epoxy resin on a polyester (PU) board is fine. The reverse is not. If you're unsure which board you have, use epoxy — it works on both.
How to tell:
- PU/polyester — heavier, usually a visible stringer down the middle, slightly yellowed with age, sounds duller when tapped.
- EPS/epoxy — lighter, whiter foam, often stamped "EPOXY" near the tail, brighter sound when tapped.
Most modern boards labelled as epoxy are EPS. If in doubt: epoxy, or UV-cure epoxy resin.
Second, the rule that saves repairs
Get the water out before you fix anything.
If the ding has been open in the water, the foam inside is wet. Seal wet foam under resin and you trap moisture that will delaminate the repair, stain brown, and add weight permanently.
Stand or lay the board so that the ding is the lowest point — that's what lets the water drain out rather than pool inside. For a nose ding that means nose-down; for a tail or rail ding, orient it accordingly. Leave it in a warm, shaded, dry place for at least 24–48 hours, longer if it took a proper soaking. Not in direct sun — heat can delaminate and expand trapped air — and not with a hairdryer on full.
If water dribbles out when you tip it, it's not ready.
Types of damage, and what each needs
Pressure dents — shallow dimples in the deck from knees and feet. Cosmetic. Don't repair them; they don't let water in.
Cracks and stress fractures — hairline splits in the glass, often along the rail or under the front foot. They do let water in slowly. Worth sealing.
Open dings — glass broken through, foam visible. Fix before surfing again, or the board takes on water every session.
Rail dings — same as above but harder, because a rail is a curve and needs shaping. Doable, just fiddly.
Nose and tail crunches — often crushed foam under broken glass. Needs foam filler before glassing, otherwise you're bridging a hole.
Fin box and leash plug damage — structural, and this one is a safety issue as much as a gear one. A leash plug that rips out in the water takes your flotation with it, which on a big cold day is a serious situation surf safety. This is where amateur repairs most often fail. Take it to a shaper.
Snapped boards, buckles, or delamination across a large area — professional job. Not worth attempting.
What you need
A basic kit:
- UV-cure resin (Solarez or similar) — epoxy version unless you're certain the board is PU. Cures in minutes in sunlight, ideal for small dings.
- Fibreglass cloth for anything structural.
- Sandpaper — around 80 grit for prep, 150–220 for shaping, 400+ for finish.
- Masking tape, acetone or isopropyl alcohol, clean rags.
- Nitrile gloves, eye protection, dust mask.
Safety, briefly but seriously: work outdoors or somewhere well ventilated — resin fumes are genuinely unpleasant and not good for you. Wear gloves; resin is a sensitiser and repeated skin contact causes real allergic reactions. Always wear a mask when sanding — fibreglass dust is nasty in your lungs and itchy on skin. Keep resin off surfaces you care about.
The repair, step by step
1. Dry the board. As above. Don't skip this.
2. Clean and open up the ding. Remove loose, cracked or lifted glass around the damage — if it's delaminated it has to come off, or your repair sits on a void. Trim frayed glass back to solid material. Wipe with acetone or isopropyl and let it flash off.
3. Sand the area. Key the surrounding glass with 80 grit, feathering out a couple of centimetres past the damage. Resin needs a rough surface to grip; it won't bond to shiny gloss coat.
4. Fill crushed foam. If foam is missing or crushed, fill it first with a filler or thickened resin and let it cure, then sand flush. Don't try to bridge a hole with resin and cloth alone — it'll be weak and it'll sink.
5. Laminate. Cut fibreglass cloth slightly larger than the ding. Lay it on, wet it out with resin until the weave goes clear, and press out air bubbles from the centre outwards. For anything structural use two layers, the second slightly larger.
6. Cure. UV resin: direct sunlight, a few minutes; keep it covered until you're ready. Two-part resin: follow the mix ratio exactly — guessing the ratio is the most common reason a repair stays tacky forever — and give it the full cure time.
7. Sand back. 150–220 grit to level the repair flush with the surrounding surface, then 400+ to finish. Take your time; a lumpy repair drags and catches.
8. Optional finish coat. A thin gloss or sanding-resin coat, sanded smooth, if you want it tidy. Purely cosmetic.
When to stop and go to a shaper
- Anything involving the fin boxes, leash plug or stringer.
- Delamination over a wide area.
- Buckles or snaps.
- Anything on a board you actually care about.
A professional ding repair is usually cheap relative to the board. A failed DIY repair on a structural area can write it off.
Prevention, which is cheaper than any of this
Use a board bag — most dings happen in cars, on roof racks and in hallways, not in the water travelling with surfboards. Don't leave a board in a hot car or in direct sun. Don't stand it upright where it can blow over. Rinse and dry it. And check it after every trip so a hairline crack doesn't become a waterlogged nose.
Check your leash while you're at it — the cord, the rail saver and the cuff velcro. It's the cheapest piece of safety equipment you own and the one people replace only after it fails.
And when the board's fixed
Find a spot that's working today — ideally something friendly while the repair beds in.