weather, sun, ozone
At NEDC, we discuss types of gaskets with customers all of the time. It can range from high temperature gaskets, to fuel resistant gaskets. In this blog, we wanted to discuss weather resistant gasketing materials. Another thing I’ve heard customers called weatherproof gaskets is “outdoor gaskets”.
Factors that I’d consider for Weather Resistant/Outdoor Gaskets
-Freezing/Freeze Resistant
A gasket that is exposed to constant weathering will also at some point in its life be exposed to freezing, and refreezing. When this happens, some materials will crack- thats what we want to avoid. When choosing a gasketing material for your weathering application- consider its temperature range, and its ability to resistant cracking through weathering. In the gasket world, we call these temperatures glass transition temperature, or when the gasket becomes extremely brittle like glass. A common standard we see is ASTM D2137.
-UV/Ozone Resistance
A gasket that is exposed to weathering will see a lot of ozone, and a lot of sun throughout its career. When reviewing gasketing materials- consider the sun, and consider the ozone it will be exposed to. There is a lot of Ozone at ground level, and this type of oxygen can age, and crack gasketing materials. The standard is ASTM D1171.
-Temperature Resistant- high, and low
Temperature Resistance obviously goes two ways. It can include the high temperatures that are common in places like Arizona where the temperature easily reaches 120°F. It can also include the coldest areas in Alaska.
-Low Compression Set
Low Compression Set is a requirement. Overtime, gaskets take a “set” which means it doesn’t provide as much pushback to properly seal. When choosing a gasket for outdoor settings, its good to find a gasket that has a low compression set.
Choices of Material for Weatherproof Gasketing
Before I present choices of material I’d consider- I’d also like to add that some materials seem to meet alot of the criteria above pretty easily, while others meet some.
Silicone Rubber- #1 option recommended for outdoor gaskets to test- Highly recommended Weatherproof Gasketing
-High/Low Temperature Range, i.e doesn’t freeze, withstands high temperatures
-Low Compression Set, Silicone Rubber takes the lowest set of any material we could suggest.
-UV/Ozone Resistance
-High customability
Specifications to consider: A-A-59588 2A/2B, ZZR765 2A/2B, AMS-3302, AMS-3303, or AMS-3304.
Polyurethane Rubber
-Decent high/low temperature range, suffers on the lower end
-Good compression set
-Good UV/Ozone Resistance
Neoprene Rubber
-Lower compression set
-Most grades have a good UV/Ozone resistance
-Moderate high/low temperature range
EPDM Rubber- Good to great
-Good high/low temperature range
-Good compression set
-Good UV/Ozone Resistance
Expanded Foam/Sponge Options-
all of the above materials have expanded foam/sponge options that you can choose from. These options are typically closed cell options- however, in the case of Polyurethane- we are usually discussing PORON which is typically an open cell option. However, all the above other options such as silicone sponge, EPDM Sponge, and Pure Neoprene Sponge are recommended for outdoor, or weatherproof applications.
Weatherproof Gaskets versus Weatherstripping
We added this because we thought it may be confusing. Weatherstripping it cut thin strips, or thin rolls of material that look like the picture right next to this. Weatherproof Gaskets are complete cut gaskets that look like this. Typically weatherstripping
Adhesive Tape/PSA Options for Weather Resistant Gaskets
Typically, when customers are asking for an adhesive backing to accompany the gasket I’d suggest an acrylic based adhesive backing. I have a few reasons this:
- Cost- silicone based adhesive backing tapes can run the cost up as they are significantly more expensive than their acrylic counterparts.
- While some silicone tapes are going be required for a gasket that is in weather, acrylic based tapes are usually a good option for the mix of properties that is required. For example, acrylic tapes have solvent resistance, good general temperature resistance, and long shelf life.
Adhesive Acrylic Tapes to Consider for Weather Resistant Gasketing:
3M 9485PC- a good tape that has a good balance of properties- utilizing the Adhesive 350 that has a good adhesion to many surfaces, yet has good short term resistances to high temperatures, and low temperatures.
3M 9472- Our in house adhesive that we use across customers. This tape has a wide temperature range, and a good balance of properties- oftentimes used with signage, and displays.
3M 9472LE- has a good balance of properties- but can stick to lower surface energy surfaces due to its adhesive, 300LSE, compared to 3M 9472 adhesive 300.
More Information/Cutting of Weatherproof Gaskets
At NEDC, we die-cut, waterjet-cut and laser-cut gaskets that are weather resistant. In addition, as mentioned above, we can add adhesive backed options. For more information on weather resistant, or outdoor gaskets, please contact sales@nedc.com.