Plastic Round Bulb Seals

Plastic round bulb seals for casement windows have a compressible bulb that seals the gap between surfaces. These window seals also have a mounting mechanism that can use a pressure-sensitive adhesive (PSA) tape for ease-of-installation. The bulb and stem sections of the seal can be made of different materials, or the same material in different durometers.

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Round Bulb Seals

Vip Rubber and Plastic of La Habra, California (USA) makes round bulb seals for crank-out window manufacturers. Minimum order quantities apply, and we do not keep these products in stock for small orders. Lead times vary, so contact us to discuss your window sealing application.

Santoprene Round Bulb Seals vs. Flex PVC Round Bulb Seals

Santoprene, a thermoplastic elastomer (TPE), is often used with plastic round bulb seals because it has excellent compression set. Flexible polyvinyl chloride (PVC), or Flex PVC, can be used instead, but this polymer may over-compress and fail to provide a proper long-term seal.

Depending on the application, however, you may need a product with a bulb that’s made of Flex PVC and a mounting mechanism made of rigid PVC. Vip can help you with material selection. On our website, we group round bulb seals with other types of plastic extrusion profiles.

Styles and Types of Plastic Bulb Seals

There are many different types of custom plastic round bulb seals.

Push-in bulb seals allow the mullion to take up a large amount of space.
Push-in bulb seals with fins are used in specialty window applications.
Half-round bulb seals have a half-moon shape instead of a ball-like shape.

Plastic bulb seals also come in a variety of sizes for casement windows, a popular window style that is hinged at the side and opens outward toward the left or the right. Vip helps door and window manufacturers to choose the best glazing seals.

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