INSIGHTS: HOW HEAT AFFECTS YOUR BOARD

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Wing

16 july 2025 0

Direct sun exposure and the greenhouse effect inside your vehicle can have serious consequences for your board. Here’s a full explanation, and our recommendations to help you avoid trouble.

At GONG, we offer true full PVC sandwich boards, featuring a hydrophobic shell that completely wraps the foam core. This gives you unmatched durability and performance. A level of construction rarely found on the market, and one we’re proud to offer as standard.

However, be aware that even this premium, lightweight, ultra-tough technology is still subject (like all composite tech) to the physical laws governing epoxy behavior under heat.

Underestimating the effects of sun exposure, hot storage environments, or extreme changes in heat or pressure can lead to partial or even total delamination of your favorite wing, kite, SUP, or surfboard.

Let’s break it down:

The risk
The causes
Visible and invisible consequences
Best practices

Wing foiler: Pamella, GONG team rider, with her Cruzader Point FSP Pro, Droid Boom wing, and Fluid setup.

1. What’s the risk?

Heat is a threat to all composite boards due to the properties of epoxy resin used in laminating the layers that surround the foam core.

Epoxy typically begins to lose its mechanical properties at about 30°C above its curing temperature. At GONG, we cure our boards at around 50°C or more, meaning they retain structural strength up to roughly 80°C under normal conditions.

Above this threshold, epoxy starts to soften and significantly loses mechanical rigidity and structural integrity. Meanwhile, the air inside the board expands and pushes outward on the laminate under massive pressure.

When this happens, the structure can fail, seriously compromising your board’s mechanical strength.

2. What causes overheating?

You might think 80°C is a safe margin, but in reality, there are situations where your board’s temperature can climb alarmingly fast.

The main culprits are:

Direct sun exposure
The greenhouse effect inside a vehicle
Their combined effects (e.g., board left behind a car window or windshield)

Even in an outside temperature of just 20°C, a surface exposed to direct sun can heat up quickly:

Black surface: 70–80°C
Red surface: 65–75°C
Blue surface: 60–70°C
White surface: 50°C

For every 5°C rise in air temperature, the surface temperature can rise 5–7°C. So even lighter colors are at risk when the shade temperature reaches 25–35°C.

Now imagine an environment rising from 20°C to 50°C inside a car due to the greenhouse effect. Even the surface of a white board can easily exceed 80°C under these conditions.

Is it safe in the car if the board isn’t in direct sunlight? Not necessarily. The greenhouse effect alone can raise your car’s interior close to 80°C on a 40°C day. So even if the board is shaded or in a board bag, it’s still at risk.

Other things to watch out for:

Proximity to heat sources
Sudden temperature changes (e.g., going from cold water to a warm van)
Major pressure shifts (e.g., air travel, mountain passes)

These all cause the same damaging effects.

3. Visible and invisible damage

When the epoxy resin softens too much, the stiff internal fibers (glass or carbon) create tension and stress marks. The laminate expands into bubbles, separates from the EPS foam, and causes visible surface bumps or distortions.

This delamination typically occurs when the resin softens temporarily and internal air pressure pushes outwards, making the fibers visibly tense.

This delamination can be visible as small or even large bubbles on the surface. It can also be invisible. By pressing on the affected area, you can usually feel a void beneath the fiber. Additionally, when opening a board after such damage, one almost always finds a collapse of the foam core that has “melted” due to heat penetrating deep into the board.

If the delamination is localized, it is entirely possible to have your board repaired by a professional who will restore it to like-new condition. This involves carefully removing the delaminated area, assessing the extent of the damage, rebuilding the laminate layers, and restoring the finish. If the delamination is widespread, the cost of such an extensive repair may quickly exceed the value of the board.

So be alert to the warning signs:

Any surface anomaly: bumps, bubbles, wrinkled skin, visible fiber.
Invisible contraction of the laminate: it has shifted, but the damage is still hidden. Probe the surface by pressing gently with your thumb. If you feel a void or an air pocket, it is recommended that you consult a professional ding repair for advice.

4. Best Practices:

First, note that there is no risk when your board is in the water or stored inside a board bag in a well-ventilated area. However, direct sun exposure on calm days must absolutely be avoided, as well as storing your board in a vehicle when it's very hot.

Also note that our full sandwich boards are equipped with an automatic vent screw specifically designed to prevent internal air pressure build-up. This feature protects you in the vast majority of cases. However, in the event of exposure to excessively intense and rapid heat, the vent screw may not release internal pressure fast enough to prevent damage.

Recommendations:

Always use a board bag outdoors to avoid direct exposure to sunlight, which can cause your board's temperature to rise quickly. Shade is your best friend.
When exposed to the sun, place your board bag with the reflective bottom, or its lightest colored side, facing upward. This is a must if you're strapping your board to the roof of your vehicle.
If leaving your board in your vehicle on a sunny day is your only option, use a sunshade on the windshield, park in the shade, etc. These simple measures are highly effective, though not always sufficient.
Be aware that slightly keeping your windows open (less than 3cm) has very little effect on the interior heat of your vehicle.
During heatwaves, it’s best to store your board indoors.

A heat spike is a bit like a sunburn as just a few minutes of exposure can do damage. A cloudy sky doesn’t always provide adequate protection. So always be vigilant.

All composite boards are affected, and we remind you of this with warning stickers on our boards that advise against direct sun or excessive heat exposure.

Taking care of your board doesn’t require much effort or time. Look after it, and it’ll return the favor!