The Ultimate Surfboard Repair Guide
Why Read This Guide?
Read this guide if you’re looking to become a more well-rounded and self-sufficient surfer by gaining some DIY surfboard repair skills. The methods outlined below are for permanent, almost good-as-new repairs.
When & Why to Fix a Surfboard
Not all surfboard damage is an immediate concern. Often, surfboards absorb bumps and scrapes that cause pressure dings, or indentations, in the glass that do not result in cracking the glass. As long as they’re not too large, these can be seen as minor and not in need of immediate repair.
A great example of these kinds of dings are heel dents on the top of a surfboard or pressure dents on the bottom. Most of the time these dings are hidden by surf wax anyway, so no need to spend precious time sanding and glassing a heel dent when you could be surfing.
The dings worth taking time to repair are those that have cracked the fiberglass and penetrated down to the foam of the surfboard. To identify these dings, drag your fingernail along the surface of the glass and over the crack. If your fingernail catches an edge of the crack, fix the ding as soon as possible. When the fiberglass is cracked enough to catch a fingernail, water will penetrate the foam core and over time the fiberglass will begin to separate from the foam. Over time this weakens your board and will quickly turn a small repair into at worst a completely broken board. When in doubt, fix early and fix often!
Jump to Section
PU vs Epoxy: Identifying The Construction of a Surfboard
When to Take a Repair to a Professional or Get a New Board
Key Tips to Remember
How to Repair a PU Surfboard
How to Repair an Epoxy Surfboard
PU vs Epoxy: Identifying The Construction of a Surfboard
Before we repair a surfboard, we need to know what materials were used to build it. Generally speaking, most surfboards are built the same: a foam core that’s wrapped or “glassed” in a watertight fiberglass shell. The devil lies in the details here, namely the kind of resin used to glass the board and the type of foam underneath.
Some boards begin life as a polyurethane (PU) foam blank that is shaped and then glassed with polyester resin. When it comes to materials, these PU surfboards are the easiest to repair. Ideally, you want to use a polyester resin to match the strength and weight of the board, but only if you’re 100% certain you’re working with a PU Surfboard.
In a pinch, you have the option of using epoxy resin on a PU surfboard, just note that epoxy is much harder than polyester and will create a weak bond around the edges of the repair where the epoxy meets the polyester glass. Repairs on PU surfboards using epoxy should be considered as temporary repairs and sanded out and repaired later with polyester resin as soon as possible.
Most surfboards are built with an expanded polystyrene (EPS) foam blank and glassed with epoxy. If your surfboard does not have a traditional wood stringer down the center, it’s likely it’s an EPS or other type of epoxy construction.
With epoxy surfboards, you must use epoxy resin. If you try using polyester resin on an epoxy board, not only will it bond very poorly with the existing epoxy glass, it will melt the foam core of your board on contact. If enough epoxy comes into contact with the polyurethane foam, it could even start a fire. That will make for a very, very bad day and we want to avoid this at all costs!
If you’re ever in doubt about the construction of a surfboard that needs to be repaired immediately, go with epoxy resin. It’ll stick to almost anything, it’s easy to work with, it’s less toxic than polyester resin, and will not melt the foam core of your board. You can also always send us a picture of your surfboard here and we’d be happy to help you identify the construction of your board and recommend the best next steps for repair.
PU SURFBOARDS
Use polyester resin. In a pinch, you can use epoxy resin, but this is temporary and may need to be sanded out and repaired later with polyester resin.
EPOXY SURFBOARDS
Use epoxy resin. NEVER USE POLYESTER RESIN.
When to Take a Repair to a Professional or Get a New Board
Some types of surfboard repairs require special tools, jigs, patterns, or advanced shaping. If you’re a novice in the world of surfboard repair, know your limits. Fin box replacements, full or partial delaminations, damage that has gone all the way through the core of the board, partial or full breaks, broken stringers, broken glass on fins, or repairs where color, gloss, or gloss and polish is required are best fixed with the help of your local shaper or surf shop.
Sometimes the damage can be so bad that it’s better to just get a new board. This includes full breaks of the board, large sections of delamination caused by water intrusion, or simply old fiberglass. PU surfboards in particular will degrade in durability over long periods of time. The glass gets brittle, yellows, and becomes more susceptible to damage from minor bumps and scrapes. In all of these cases, it’s probably time to retire that board as a wall hanger and upgrade to something new.
Key Surfboard Repair Tips to Remember
- Always use proper protective equipment: Respirator, gloves, safety goggles, and proper coverage for exposed skin.
- Preparation is everything. Once the resin is mixed, you’re on the clock. Be sure to set all your masking, sand and clean the repair, cut your fiberglass, and have all your tools at arm's reach and ready to go before you mix.
- Never use polyester resin on an epoxy surfboard. Polyester will not bond well to cured epoxy, and it will melt the EPS foam in most epoxy surfboards on contact.
- When in doubt about a surfboard’s construction, use epoxy resin.
- Always stick to the instructions when mixing resins and hardeners. Measure precisely, and pay attention to outside temperature and humidity, as this will affect how these resins cure more than anything else. The higher the ambient temperatures, the quicker the resin will cure and the less time you’ll have to work, whereas if the ambient temperature is too cold, the resin may not cure at all.
- Make sure you use the right kind of mixing cups for your resin. Certain plastics will melt upon contact with resin, especially polyester resin, and nothing is worse than a big uncured resin spill.
- Know your limits. Take repairs like fin box replacements, partial breaks, or damage caused by airlines to a professional
- Outside of selecting the right materials and preparing your resin, surfboard repair can be more of an art than a science. You can (almost) always sand down a poorly done repair and start again.
How to Repair a PU Surfboard
Gather these materials: Latex gloves, respirator or dust mask, safety glasses, sandpaper in 60, 120, 220, 320, and 400 grit, sanding block for easier flat surface sanding (optional), masking tape, 4oz fiberglass cloth, PU resin and hardener, mixing cups, mixing sticks, Q-Cell filler if it’s a deep ding that requires a lot of foam replacement (optional), razor knife, squeegy or straight-edge for applying and smoothing out wet resin, acetone, several clean cloth rags, and scissors.
To get the majority of the repair materials you’ll need in one kit, check out the Ding All Polyester Repair Kit or the Ding All Super Polyester Repair Kit for larger repairs.
Make sure the surfboard ding is completely dry. A hairdryer on low can help speed up this process. Remove surf wax from around the damaged area if necessary.
Check the weather: Temperature and humidity matter when working with resin. Make sure the temperature and humidity of your working area are within the acceptable range found on the label for your resin.
Put on your respirator, gloves, and safety glasses.
Cut away all damaged glass carefully with the razor knife. Make sure to remove any damaged glass still attached to the foam inside the ding. If you discover water has at any point penetrated the ding, allow the foam to completely dry for 1-2 days after cutting away the damaged glass.
Sand the entire area and 1-2 inches outside of any cut glass into a subtle bowl shape with 60-grit sandpaper. Remember, with the bowl shape you need to make room for new fiberglass and a filler coat. This bowl shape gives strength to the edge of the ding repair, which separates permanent fixes from repairs that will need a re-do after a couple of sessions.
Clean the ding area with acetone. Do not pour acetone directly onto the surfboard. Apply acetone to a rag and gently wipe down the ding.
Apply masking tape around the area. Create a masking tape resin dam if the ding is on a rail.
For dings that have penetrated the foam, mix Qcel filler with resin and hardener to a mayonnaise consistency. If you have a very large ding to fill, go thicker with the Qcell mix, up to a peanut butter consistency.
Slowly fill the ding with Qcell filler. Use the mixing stick to make sure Qcell has penetrated all areas of the ding. Remove masking tape. Allow to dry for 24 hours, out of direct sunlight in a clean dry location.
Sand Qcell and 1-2 inches around the area with 120 grit. Clean with an acetone rag using the technique described earlier.
Prepare to glass the repair. Use scissors to cut out two pieces of 4 oz fiberglass cloth; one the same size as the sanded area, and one slightly larger. Mix your resin and hardener.
Apply masking tape around the ding area. Apply a thin layer of resin directly over the repair area. Place the smaller piece of 4 ox fiberglass cloth on the ding. Tape one edge of the fiberglass cloth to the board if the repair is on a rail to hold it in place.
Apply a thin layer of resin to the fiberglass cloth, making sure the fiberglass is completely saturated with resin. Place the larger piece of fiberglass cloth on top of the smaller piece of fiberglass cloth.
Apply a thin layer of resin to the top piece of fiberglass cloth, making sure the cloth is completely saturated with resin.
Smooth the wet fiberglass with a scraper or straight edge to remove excess resin from the repair, being careful not to move or introduce wrinkles to the wet fiberglass. We want the fiberglass to be fully saturated with resin, but not over-saturated or dripping. Too much resin will make the repair weak and heavy. Remove the masking tape. Allow to dry for 24 hours, out of direct sunlight in a clean dry location.
Once fully cured, sand the repair area. Cut away any excess new fiberglass and use 120 grit to feather the edges of the fiberglass into the rest of the board until smooth and flat. Once smooth, clean the area with acetone using the method described earlier.
Apply masking tape around the repair to prepare to hot coat. Mix up some resin and hardener, and apply a thin layer of resin to the repair to smooth out and fill in the fiberglass texture. Remove the masking tape. Allow to dry for 24 hours, out of direct sunlight in a clean dry location.
Finish sand. Sand the area smooth by moving through grits of sandpaper from 120, 220, 320, and 400 for a smooth finished surface. Be very careful not to sand completely through the hot coat.
Surf.
How to Repair an Epoxy Surfboard
Gather these materials: Latex gloves, respirator or dust mask, safety glasses, sandpaper in 60, 120, 220, 320, and 400 grit, sanding block for easier flat surface sanding (optional), masking tape, 4 oz fiberglass cloth, epoxy resin and hardener, mixing cups, mixing sticks, Q-Cell filler if it’s a deep ding that requires a lot of foam replacement (optional), razor knife, squeegy or straight-edge for applying and smoothing out wet resin, acetone, several clean cloth rags, scissors. To get the majority of the repair materials you’ll need in one kit, check out the Ding All Epoxy Repair Kit or the Ding All Super Epoxy Repair Kit for larger repairs.
Make sure the surfboard ding is completely dry. A hairdryer on low can help speed up this process. Remove surf wax from around the damaged area if necessary.
Check the weather: Temperature and humidity matter when working with resin. Make sure the temperature and humidity of your working area are within the acceptable range found on the label for your resin.
Put on your respirator, gloves, and safety glasses.
Cut away all damaged glass carefully with the razor knife. Make sure to remove any damaged glass still attached to the foam inside the ding. If you discover water has at any point penetrated the ding, allow the foam to completely dry for 1-2 days after cutting away the damaged glass.
Sand the entire area and 1-2 inches outside of any cut glass into a subtle bowl shape with 60-grit sandpaper. Remember, with the bowl shape you need to make room for new fiberglass and a filler coat. This bowl shape gives strength to the edge of the ding repair, which separates permanent fixes from repairs that will need a re-do after a couple of sessions.
Clean the ding area with acetone. Do not pour acetone directly onto the surfboard. Apply acetone to a rag and gently wipe down the ding.
Apply masking tape around the area. Create a masking tape resin dam if the ding is on a rail.
For dings that have penetrated the foam, mix Qcel filler with resin and hardener to a mayonnaise consistency. If you have a very large ding to fill, go thicker with the Qcell mix, up to a peanut butter consistency.
Slowly fill the ding with Qcell filler. Use the mixing stick to make sure qcell has penetrated all areas of the ding. Remove the masking tape. Allow to dry for 24 hours, out of direct sunlight in a clean dry location.
Sand Qcell and 1-2 inches around the area with 120 grit. Clean with an acetone rag using the technique described earlier.
Prepare to glass the repair. Use scissors to cut out two pieces of 4 oz fiberglass cloth; one the same size as the sanded area, and one slightly larger. Mix your resin and hardener.
Apply a thin layer of resin directly over the repair area. Place the smaller piece of 4 ox fiberglass cloth on the ding. Tape one edge of the fiberglass cloth to the board if the repair is on a rail to hold it in place.
Apply a thin layer of resin to the fiberglass cloth, making sure the fiberglass is completely saturated with resin. Place the larger piece of fiberglass cloth on top of the smaller piece of fiberglass cloth.
Apply a thin layer of resin to the top piece of fiberglass cloth, making sure the cloth is completely saturated with resin.
Smooth the wet fiberglass with a scraper or straight edge to remove excess resin from the repair, being careful not to move or introduce wrinkles to the wet fiberglass. We want the fiberglass to be fully saturated with resin, but not over-saturated or dripping. Too much resin will make the repair weak and heavy. Remove the masking tape. Allow to dry for 24 hours, out of direct sunlight in a clean dry location.
Once fully cured, sand the repair area. Cut away any excess new fiberglass if needed and use 120 grit to feather the edges of the fiberglass into the rest of the board until smooth and flat. Once smooth, clean the area with acetone using the method described earlier.
Apply masking tape around the repair to prepare to hot coat. Mix up some resin and hardener, and apply a thin layer of resin to the repair to smooth out the fiberglass texture. Remove the masking tape. Allow to dry for 24 hours, out of direct sunlight in a clean dry location.
Finish sand. Sand the area smooth by moving through grits of sandpaper from 120, 220, 320, and 400 for a smooth finished surface. Be very careful not to sand completely through the hot coat.
Surf.
Conclusion
By learning to repair your surfboard yourself, you gain a valuable skill that can be used at home or on the road. Whether you're dealing with minor dings or more serious cracks, being able to assess and fix damage on your own means less time spent at the repair shop and more time in the water. Remember to always match the right materials to your board's construction and know when it's best to leave more complex repairs to the professionals. With practice, you'll master the art of surfboard repair and keep your board in top shape for years to come.
