What is a Gasket?

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A Guide to Gaskets

What is a Gasket?

Put simply, a gasket is a seal between two components to prevent leakage and ingress of dust particles, water, oils, chemicals and more.

At Deltron Enclosures, they are used in our aluminium and plastic enclosures to provide an IP rating and sometimes EMI/RFI protection.

So, why don’t we just call it a seal?

There is a difference between gaskets and seals; a gasket is also known as a static seal which depends on the two mating components to be static. Whereas a seal is used to prevent leakage between two kinetic parts, for example, a pump or a rotary type motion in an engine. A seal is generally rounded and flat, while a gasket is shaped to fit the necessary components.

Gaskets at Deltron Enclosures are shaped to fit our enclosures perfectly including punched out screw holes as necessary.

What materials are gaskets made of?

Gaskets can be made from different materials, depending on the properties of the material and the demands of the application. Popular options include rubber, neoprene, silicone, cork, graphite and foam plastic. At Deltron we use neoprene and silicone rubber. The two can be used in different ways to create the desired sealing performance.

Now let’s take a look at the properties of different materials for our gaskets….

Choosing the best material for your gasket is essential to ensure performance and longevity. In the majority of applications, exposure to the elements is a critical consideration. Snow, sleet, heavy rain, UV, plus rising and falling temperatures can affect the gaskets’ sustainability; some materials may crack or fluctuating temperatures could cause the gasket to expand or freeze and consequently fail to prevent ingress.

Neoprene Sponge - open cell type with an adhesive backing

The adhesive allows the gasket to be attached to the enclosure lid in order to ease the assembly process. Neoprene sponge is used with our general purpose IP66 thin wall die cast enclosure ranges and has a number of useful properties:

- A resilient material, repels dust and moisture
- Good resistance to petrol, oils and chemicals
- Can be made with adhesive backing to aid fitting
- Can withstand high levels of compression

Silicone Rubber - closed cell type with an adhesive backing

The adhesive allows the gasket to be attached to the enclosure lid in order to ease the assembly process. Silicone rubber sponge is used with our general purpose IP68 thin wall die cast enclosure ranges as well as the heavy duty thick wall IP66 and IP68 ranges and has a number of useful properties:

- Excellent resilience to extreme high and low temperatures
- UV and ozone resistant; ideal for outdoor application
- Being an inert material, it does not react to majority of chemicals; ideal for medical or industrial applications.

Carbon Loaded Silicone Rubber

These gaskets are conductive and are used to connect the lid electrically to the base whilst still achieving IP68 protection. The electrical connection improves the enclosure’s EMC performance helping to keep radio frequency interference either inside or outside of the enclosure.

Some important considerations

The thin wall general purpose enclosures have shallow lids so it is possible to over compress the seal underneath the screws and create leaks away from the screws where the lid bows upwards. It is recommended that users comply with the following torque settings:

IP Rating       Gasket Material                      Lid Screw Torque Nm

IP66               Open cell neoprene                  0.3Nm

IP68               Closed cell silicone                   0.7Nm

IP68               Solid carbon loaded silicone     1.0Nm

However the Deltron heavy duty thick wall enclosures have an innovative two level gasket face that allows the metal of the lid to touch the metal of the base whilst allowing the perfect level of gasket compression whatever torque is used. This also means that a conductive gasket is not needed because metal touches metal.

The Deltron heavy duty enclosures are IP68 certified at the unusually severe specification of 10m submersion for 20 hours. Many people ask what happened at 20 hours, did it fail? The answer is no we just ran out of time.

Whilst Deltron has an extensive offer of standard enclosures and seal solutions we also like to offer customised products. If the standard carbon loaded seals are not conductive enough then we can supply other technologies such as material which use stainless steel of silver conducting particles. We also offer machining, IP rated glands and connectors, custom coatings, screen printing and, where volumes allow, custom geometries.

Click here to view our gaskets

For more information call: 01724 273200 or email: sales@dem-uk.com

Related Articles: What is Ingress protection (IP)?
Choosing between materials for your enclosure
Choosing Between Polycarbonate, ABS and Die-cast Aluminium

Article first published : 29|1|2019