Bonded Seal Overview

Bonded Seals (Dowty Seals, Composite Washer Seals, Gasket Seals) are a proven solution for reliable sealing in high-pressure applications. These seals consist of a metal washer with a vulcanized elastomer sealing element bonded to the inner diameter. When compressed during installation, the elastomer deforms to create a tight, leak-proof seal against both flat surfaces and threaded fasteners. They offer a reliable method for sealing bolts, pipe connections, and flange joints where leakage prevention is critical.

With a focus on quality, consistency, and availability, Global O-Ring and Seal provides bonded seals in a broad range of inch and metric sizes to meet the diverse needs of industrial applications. For more information or to request a quote on bonded seals, please call us at 832-448-5550 or submit the Product Inquiry Form.

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Advantages of Bonded Seals

Bonded seals are widely recognized for their ability to provide durable, cost-effective sealing in high-pressure and static applications. Their simple, integrated design offers several key benefits over alternative sealing methods:

  • High-Pressure Sealing: Provides a reliable seal for static connections exposed to high-pressure fluids.
  • Leak Prevention: Ensures a secure barrier against fluid and gas leaks at bolted or threaded connections.
  • Vibration Resistance: Maintains sealing integrity even under vibration, pulsation, and minor dynamic loads.
  • Corrosion Resistance: Commonly offered with protective coatings for enhanced durability.
  • Simplifies Installation: Eliminates the need for additional sealant, reducing assembly complexity.
  • Cost-Effective: Provides long-term performance with minimal maintenance.

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Standard vs. Self-Centering Bonded Seals

Bonded seals are available in standard and self-centering variations. While both provide effective sealing solutions, there are important distinctions between the two.

Standard designs feature an elastomer bonded within the washer’s inner diameter, but lack any centering feature. During installation, care must be taken to ensure the seal is properly aligned within the bore. Misalignment can lead to uneven compression, compromised sealing performance, or installation errors.

Self-centering designs incorporate an extended elastomer profile that fits snugly within the bore or around the fastener during installation. This feature keeps the seal concentric within the assembly and simplifies installation to reducing the risk of misalignment. As a result, self-centering seals offer more reliable and consistent performance, particularly in applications that require precise sealing under high pressure.

For these reasons, Global O-Ring and Seal exclusively offers self-centering bonded seals as our standard product. This design offers the added assurance of proper alignment, enhanced seal integrity, and simplified installation.

 

Materials

Bonded seals are manufactured using a carefully selected combination of materials to deliver reliable sealing performance, durability, and compatibility with a wide range of fluids and operating environments. The elastomer provides the sealing function, while the metal washer offers structural integrity. Coatings enhance corrosion resistance where applicable.

 

Elastomer Metal Coating MPa
NBR Mild Steel Zinc, CR (III) 300
FKM Mild Steel Zinc, CR (III) 300

 

NBR (Nitrile) offers excellent resistance to oil and fuel, while FKM offers superior resistance to chemicals and high temperatures. Mild steel is a strong and cost-effective choice, paired with a corrosion-resistant coating.

Custom Seal Capabilities

In addition to our standard offering, Global O-Ring and Seal provides custom bonded seal solutions to meet unique application requirements. We have the flexibility to customize key elements of the bonded seal to suit specific operational requirements, performance needs, and assembly conditions. Our team can help identify the ideal combination of materials and design features to ensure optimal performance in even the most demanding applications. Complete the product inquiry form or contact us to begin the process.

Bonded Seal Part Numbering System

 

 

 

 

 

 

Elastomer

Code

NBR

(Blank)

FKM

/V

Bonded Seal Sizes

Bonded seals are available in a wide range of sizes to accommodate both inch and metric fasteners commonly used across various industries. Our size offerings align with standard hardware dimensions to ensure proper fit and reliable sealing performance. The chart below provides detailed measurements to help identify the appropriate bonded seal for your specific application.

 

 

Ref #
Metric
IN
BSP
ID (mm)
OD (mm)
HT (mm)
ID (in)
OD (in)
HT (in)
603 M5 5.70 9.00 1.00 0.224 0.354 0.039
606 M6 898 6.70 10.00 1.00 0.264 0.394 0.039
607 M6 6.70 11.00 1.00 0.264 0.433 0.039
612 M8 8.70 13.00 1.00 0.343 0.512 0.039
613 M8 866 8.70 14.00 1.00 0.343 0.551 0.039
820 3/8 1/8 10.37 15.88 2.00 0.408 0.625 0.079
622 M12 12.70 18.00 1.50 0.500 0.709 0.059
821 1/2 1/4 13.74 20.57 2.00 0.541 0.810 0.079
627 M14 868 14.70 22.00 1.50 0.579 0.866 0.059
811 5/8 869 16.51 25.40 2.00 0.650 1.000 0.079
823 3/8 17.28 23.80 2.00 0.680 0.937 0.079
632 M18 872 18.70 26.00 1.50 0.736 1.024 0.059
633 M20 873 20.70 28.00 1.50 0.815 1.102 0.059
825A 13/16 1/2 21.54 28.58 2.50 0.848 1.125 0.098
636 M22 874 22.70 30.00 2.00 0.894 1.181 0.079
826 7/8 5/8 23.49 31.75 2.50 0.925 1.250 0.098
638 M24 875 24.70 32.00 2.00 0.972 1.260 0.079
829 1 3/16 7/8 30.81 38.10 2.50 1.213 1.500 0.098
642 M30 31.00 39.00 2.00 1.220 1.535 0.079
643 M33 33.70 42.00 2.00 1.327 1.654 0.079
830A 1 5/16 1 33.89 42.80 3.20 1.334 1.685 0.126
832A 1 5/8 1 1/4 42.93 52.38 3.20 1.690 2.062 0.126
833A 1 7/8 1 1/2 48.44 58.60 3.20 1.907 2.307 0.126
834 2 1/8 54.89 69.85 3.20 2.161 2.750 0.126
836A 2 60.58 73.03 3.20 2.385 2.875 0.126
839 2 1/2 76.08 90.17 3.20 2.995 3.550 0.126

 

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