A Guide to Bonded Seals: What They Are and Why You Need Them

July 25, 2025 – by Eastern Seals

When it comes to reliable sealing solutions, bonded seals are a staple across many industries—providing an effective, cost-efficient method of preventing leaks in high-pressure systems. At Eastern Seals, we offer a wide range of bonded seals that meet the demanding needs of modern engineering and manufacturing. Whether you’re working in hydraulic systems, automotive applications, or industrial machinery, our bonded seals are designed to perform.

What Are Bonded Seals?

A bonded seal—also known as a Dowty seal—is a metal washer with a vulcanised rubber insert bonded to the inside. This combination of materials allows the seal to provide both strength and flexibility. The metal washer resists deformation under pressure, while the elastomeric sealing lip ensures a tight seal against fluid or gas leakage.

Bonded seals are typically used in conjunction with threaded fasteners, such as bolts and screws, to seal fluid connections and prevent leakage. They are particularly popular for hydraulic and pneumatic applications because of their ability to maintain a tight seal under high pressure.

Key Benefits of Bonded Seals

• High Pressure Resistance: Bonded seals can handle pressures up to several thousand psi, depending on the size and material.
• Reliable Sealing: The rubber element ensures a tight, leak-free seal even under vibration or thermal expansion.
• Versatility: Available in a wide range of sizes and materials to suit different applications and fluids.
• Easy Installation: Simple to use and requires no special tooling.

Materials and Custom Options

At Eastern Seals, we supply bonded seals in a variety of combinations including stainless steel, mild steel, and different rubber compounds such as Nitrile (NBR), Viton®, EPDM, and more. This allows us to offer solutions that are compatible with a wide range of fluids and temperatures.

We also offer self-centering bonded seals for easier installation, and can provide custom sizes or materials on request.

Shop Bonded Seals at Eastern Seals

Whether you’re looking for standard sizes or specialised materials, Eastern Seals has you covered. Browse our full range of bonded seals here or shop directly from our online store.

Need help choosing the right seal? Contact our expert team today—we’re here to help you find the perfect sealing solution.