Trim seals are rubber gaskets that provide sealing and insulation for doors or hatches with rounded corners. They consist of a compressible rubber bulb and a solid retainer, or trim section, that attaches to an edge or flange. When the door or hatch is closed, the trim seal’s bulb compresses. When the door or hatch is open, the bulb returns to its original size and shape.    

All in One Bulb and Trim

Like most standard rubber products, trim seals usually come in black; however, rubber gaskets in custom colors are also available. Trim seal finish is usually smooth, but you can also order these seals with a textured finish instead. Many engineers and buyers are familiar with products from Trim-Lok, but all in one bulb and trim from Elasto Proxy provides valuable options and advantages.   

For example, bulb trim seals from Elasto Proxy have a one-piece construction for long-lasting performance. Plus, when you order rubber gaskets from us, you can buy them in low-to-medium volumes so that you don’t have to pay for more than you need. Elasto Proxy doesn’t sell to consumers, but our low minimum order quantities (MOQs) are popular among industrial buyers and the engineers they support.

Contact us to request a quote or keep reading to learn some trim seal basics.

Trim Seals: The Bulb’s Four Features

The bulb section of a trim seal has four important features:

  • Material
  • Durometer
  • Shape
  • Location

There are also trim seal measurements for the bulb that you need to make.

Bulb Material

Trim seal bulbs are made of a sponge rubber, usually EPDM or TPE, that provides environmental sealing. EPDM rubber remains flexible at low temperature and resists water, weather, sunlight, ozone, and aging. TPE is also weather-resistant, but it’s recyclable, too. Although TPE bulb trim costs more than EPDM bulb trim, thermoplastic elastomers (TPEs) are growing in popularity.  PVC is also a trim seal material.

Bulb Trim Durometer

The  durometer, or hardness, of a bulb is measured on the Shore A scale. Typically, a medium-durometer rubber is used for the bulb. Otherwise, if a bulb is too soft, it won’t “bounce back” after an applied force (such as a door or hatch) is removed. This is called compression set and represents a leading cause of seal failure. Yet, if a bulb is too hard, the door or hatch won’t close easily or properly.

Bulb Shape and Location

Most bulbs are round, but trim seals can also have bulbs that look like a half-moon with a flat bottom. There are teardrop-shaped bulbs with an extended lip, too. The location of the bulb can also vary. Depending on how the door or hatch opens, you may need a trim seal with top bulb. This type of rubber gasket is called a vertical trim seal. You can also choose a trim seal with side bulb instead.

Trim Seals: The Retainer’s Four Features

The trim, or retainer, section of a trim seal has four important features.

  • Material
  • Durometer
  • Added Gripping
  • Extra Impact Resistance

There are also trim seal measurements for the trim that you need to make.

Trim Material and Durometer

The trim portion of the seal is usually made of a solid rubber like EPDM or TPE, or a plastic like PVC. For greater impact resistance, you may need a trim durometer that is harder than the bulb durometer. That’s why this type of all in one bulb and trim is called a dual durometer seal.

Added Gripping and Extra Impact Resistance

For added gripping, the retainer section of a trim seal can have interior tongues. For extra impact resistance, the trim section can contain steel wire or segmented steel cores. Remember, however, that cutting metal-filled rubber by hand is time-consuming and can result in material waste from mist-cuts.  

All in One Trim Seals from Elasto Proxy

Elasto Proxy sources trim seal materials from trusted suppliers and then fabricates them using our water jet or abrasive water jet cutting equipment. We can also bond cut lengths to provide you with finished gaskets that arrive ready-to-install. With our 30+ years of experience, we can help you with trim seal installation, too.

Are you ready for better all in one trim seals? Contact Elasto Proxy.

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