Automotive Waterproofing Solutions

As modern vehicles grow more complex and connected, the need to protect sensitive components from water ingress becomes critical. From engine control units to infotainment systems, the rising level of electronics in automotive environments brings increasing challenges for waterproofing.

How waterproof does the material need to be?

Waterproofing in automotive design isn’t a one-size-fits-all solution. Consideration must be given to where the part is in the vehicle, what kind of moisture it might encounter, and for how long. Based on these variables, waterproofing levels are typically chosen to meet specific Ingress Protection (IP) ratings.

Understanding IP ratings

The IP rating system classifies and rates the degree of protection provided by mechanical casings and electrical enclosures against intrusion, dust, accidental contact, and water. Common automotive waterproofing targets include:

• IP54: Protected against limited dust ingress and water spray from any direction. Suitable for interior components.
• IP67: Completely dust-tight and protected against immersion in water up to 1 meter for 30 minutes. Ideal for engine bay electronics and external sensors.
• IP68: Same as IP67 but capable of continuous immersion under conditions specified by the manufacturer. Used in areas likely to face high pressure or submersion.
• IP69K: Withstands high-pressure, high-temperature water jets. Often required for parts exposed to harsh cleaning processes, like undercarriage sensors in commercial vehicles.

What needs protecting?

• ECUs (Electronic Control Units): These critical components manage everything from braking to infotainment. Positioned throughout the vehicle, they require varying degrees of waterproofing.
• Connectors: Even a small ingress point at a connector can cause corrosion and signal loss.
• Battery packs (especially EVs): Water intrusion can lead to catastrophic failure in electric vehicles.

Methods of protecting electronics

Potting compounds

Potting involves filling an electronic assembly or cavity with a protective compound, often epoxy, polyurethane, or silicone, to encapsulate the entire component. This creates a solid barrier against water, dust, vibration, and chemical exposure.

Silicone foam potting

Silicone foam is a specialised form of potting compound that offers exceptional long-term stability, resists oxidative deterioration, and does not react with other elements, ensuring it’s a safer choice for both human health and the environment. Plus, being a lightweight foam, it is ideal for low-strain applications and projects where weight is a concern.

Conformal coatings

Conformal coatings are thin polymer films applied over electronic circuits to protect against moisture, dust and chemicals. Unlike potting, coatings conform to the shape of the component without encapsulating it entirely but do not offer as much waterproofing protection.

Common types include:

• Acrylics: Easy to apply and remove, good general-purpose protection.
• Silicones: Withstand wider temperature ranges.
• Polyurethanes: Offer chemical and abrasion resistance.

Nano coatings

Nano coatings are ultra-thin layers that protect electronic surfaces from water and corrosion. These coatings are often based on fluoropolymer or ceramic materials and offer excellent water resistance with minimal impact on weight or design.

Advantages

• Superior water repellence: Nano coatings actively repel water, offering better protection for high-risk electronics.
• Minimal impact: They are ideal for compact or delicate assemblies.

In-place gaskets

In-place gaskets are materials or specially formulated sealants applied between surfaces to form a water-tight seal once compressed. Unlike traditional pre-cut gaskets, these are dispensed directly onto parts in a liquid or foam form before curing.

Cork as a gasket option

ETP700 is a high-performance cork-rubber composite known for its excellent compressibility and resistance to fluids. It is also fire retardant, making it an ideal solution for sealing electric batteries.

Liquid gaskets

Permabond’s MH196 allows sealing between rigid, mating metal surfaces and applications where a durable, leak-proof seal is required. It does not disintegrate so there is no blockages or leaks and one bottle can fit all applications.

In many cases, engineers use a hybrid approach. For instance, a sensor module may use nano coating on the PCB, conformal coating on connectors, and an in-place gasket on the housing.

Get in touch to find out how your electronics can perform better and last longer.