Extruded rubber seals come in many different shapes, but there are four that are especially common.

  • P-seals
  • D-seals
  • E-seals
  • Lip seals

In this article from Elasto Proxy, you’ll learn when to choose each type of extruded rubber seal, how to buy these rubber products, and how to install them.

P-Seal Catalog
P-Seal from Elasto Proxy's Catalog. Click the image to get the catalog.


P-seals look like the letter P and have a rounded bulb and a flat stem. The bulb compresses to fill a gap and provide the sealing action. The stem is used for attaching the gasket to a substrate. You can buy these extruded rubber products as coils that you cut or finish yourself, or you can purchase cut lengths or finished gaskets. Applications include building and construction.

With P-seals, an installer lays the tail of the seal atop a flat piece of metal. The installer than rivets the rubber stem into place or lays a piece of bar stock on top of the tail prior to fastening the gasket. Either way, P-shaped seals are installed with mechanical fasteners instead of with adhesives. If you buy finished gaskets from Elasto Proxy, we can use our water jet cutting to create holes for the fasteners.

D-Seal Catalog
D-Seal from Elasto Proxy's Catalog. Click the image to get the catalog.


D-seals look like the letter D and have a half-moon bulb that’s flat on the bottom. The bulb provides sealing under pressure, such as when an enclosure door is closed. Typically, D-seals are made of sponge rubber. You can buy them as coils, lengths, or finished gaskets, and Elasto Proxy can apply adhesive pressure sensitive adhesive (PSA) tape to them to speed installation.

D-seals are great for sealing the gap between a long piece of sheet metal and a surface such as the edge of a door. Long pieces of thin-gauge sheet metal might look perfectly straight, but they’re not. Along the length of the metal, bowing creates gaps between the surface to seal and the gasket. D-shaped seals fill these gaps and withstand pressure points where compression is greater because the gap is narrower.  

E-Seal 3D
E-Seal 3D Model from Elasto Proxy. Click the image to learn more.


E-seals look like a lowercase letter E and have three parts.

  • The top of the seal is a half-moon bulb that supports compression.
  • The bottom of the seal has a flat, straight tail that an installer lays atop a substrate.
  • The middle of the seal contains a gap or slot where the installer inserts metal bar stock.

With E-seals, the installer rivets through the bar stock and the rubber tail to reach the substrate. If the gap or slot is especially narrow, the installer may need to move the bulb during fastening.

E-seals are used in applications such as food processing that require mechanical fastening instead of adhesives because of the heat and chemicals associated with repeated cleaning. To withstand these environments, silicone or fluorosilicone E-seals are used. Both types of rubber compounds can resist high temperatures, but fluorosilicones provide greater chemical resistance.

Lip Seal
J-Seal from Elasto Proxy featured in Water Technology Magazine. Click the image to read the article.

Lip Seals

Lip seals have an extended lip or edge instead of a rounded bulb. Some of these extruded rubber seals look like the letter V where one leg of the V lays flat and the other leg is raised. Other lips seals look more like the letter C or J instead, depending on their curved section. There are also lip seals with a gap or slot that’s designed to accommodate metal bar stock for fastening.

Smaller lip seals attach with adhesives and larger lip seals attach with mechanical fasteners. For example, the large lip seals used in water filtration systems have a flat section that is fastened to the bottom of a metal gate. The lip is compressed against a concrete floor to form a tight seal. Lip seals don’t need full compression to provide sealing, however, and that makes them different from other rubber seals.   

Extruded Rubber Seals from Elasto Proxy

Elasto Proxy supplies P-seals, D-seals, E-seals, lip seals and other types of extruded rubber seals as coils, cut lengths, or finished gaskets. Because we specialize in low-to-medium volumes, we can often offer lower minimum order quantities (MOQs) than you’ll find elsewhere. Also, with our added-value services, we can provide you with ready-to-install gaskets that help you save time on your assembly line.

Ready to learn more? To request a quote or discuss your industrial sealing application, contact us.

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