OSK™ O-Ring Kit for use with Graco Fusion CS 256490 Commercial Grade

The OSK™ Commercial Grade O-Ring Kit for Graco Fusion CS 256490 is engineered using Viton® FKM (fluoroelastomer) for exceptional resistance to chemicals, oils, and high temperatures in spray foam and polyurea systems. Designed as a direct replacement kit for Graco OEM 256490, it delivers outstanding sealing performance, long service life, and reduced downtime — all at a cost-effective, commercial-grade value.

This complete repair kit ensures leak-free operation and easy maintenance for professionals using the Graco Fusion CS gun. Each O-Ring is precision-molded to OEM dimensions to ensure a perfect fit without measuring or modification.

Material & Performance Details

Material: Viton® FKM
Durometer: 75 Shore A
Color: Brown or Black

Viton® FKM is a premium fluoroelastomer known for its balance of heat resistance, chemical compatibility, and long-term sealing performance. This material maintains flexibility and resilience even under aggressive spray conditions involving isocyanates, solvents, and hydraulic oils.

Excellent resistance to:

• Hydraulic oils and lubricants
• Isocyanates and polyurea chemicals
• Aliphatic and aromatic hydrocarbons
• Silicone oils and greases

Limited capability with:

• Hot water and steam above 200°F (93°C)
• Organic acids

Not compatible with:

• Ketones (MEK, acetone)
• Skydrol® phosphate ester fluids

Kit Contents

Applications & Use Cases

The OSK™ Commercial Grade Viton® FKM Kit is designed for maintenance professionals and contractors requiring dependable sealing in high-pressure spray systems. Ideal for:

• Graco Fusion CS spray foam and polyurea guns
• Coating and adhesive application equipment
• Industrial maintenance and rebuild operations
• Hydraulic and chemical fluid sealing

Key Specifications

• Material: Viton® FKM (fluoroelastomer)
• Durometer: 75 Shore A
• Color: Brown / Black
• Temperature range: -15° to +400°F (–26° to +204°C)
• Pressure rating: Up to 3,000 psi (system dependent)
• Certifications: ISO9001:2015 quality processes

Why Buy from The O-Ring Store LLC

The O-Ring Store LLC is your trusted source for precision sealing products. Every OSK™ Kit is assembled in the USA under ISO9001:2015-certified quality management for consistent performance and reliability.

• USA stock for fast delivery
• Same-day shipping on in-stock items
• Custom and OEM rebuild kits available
• Full lot traceability and documentation on request
• Expert technical support and material cross-references
• Competitive pricing with no compromise on quality