Comprehensive Guide to Gasket Materials
In industrial sealing, the choice of Gasket Materials is the single most critical factor determining the success or failure of a sealed joint. It dictates performance under pressure, temperature extremes, and chemical exposure, directly impacting safety, efficiency, and operational costs. At Kaxite Seals, we engineer and supply a vast portfolio of advanced gasket materials designed to meet the rigorous demands of modern industry. This guide provides a detailed overview of key materials, their technical specifications, and practical considerations for selection.
Critical Parameters for Gasket Material Selection
Selecting the optimal gasket requires careful analysis of the application's specific conditions. The following parameters must be evaluated:
- Temperature Range: The minimum and maximum continuous operating temperatures the material must withstand without degrading, losing resiliency, or becoming brittle.
- Pressure (PSI/Bar): The internal pressure of the system, including potential pressure spikes or vacuum conditions.
- Media Compatibility: The chemical resistance of the material to the fluids, gases, or process media it will contact.
- Compression Set Resistance: The material's ability to recover its original thickness after prolonged compression, crucial for maintaining a tight seal over time.
- Creep Relaxation: The tendency of a material to lose clamping force under constant strain and temperature, leading to potential leakage.
- Tensile Strength & Density: Indicators of the material's mechanical robustness and structural integrity.
- Applications: Typical industries and joint types where the material performs best.
Detailed Specifications of Kaxite Seals Gasket Materials
Below is a technical comparison of our core material families. These specifications serve as a guideline; our engineering team can provide precise data sheets for your specific application.
| Material Type | Temperature Range | Max Pressure | Key Media Resistance | Compression Set | Common Applications | Kaxite Product Series |
|---|---|---|---|---|---|---|
| Expanded PTFE (ePTFE) | -450°F to 500°F (-268°C to 260°C) | Up to 3000 PSI (207 bar) | Excellent resistance to virtually all chemicals, solvents, and aggressive acids/bases. | Excellent | Chemical processing, pharmaceutical, food & beverage, high-purity systems, flange gaskets. | KX-ePTFE Pro |
| Compressed Non-Asbestos Fiber (CNAF) | -100°F to 750°F (-73°C to 399°C) | Up to 1500 PSI (103 bar) | Good resistance to water, steam, oils, fuels, and moderate chemicals. Specific grades vary. | Good to Very Good | General industrial, water/wastewater, steam lines, oil & gas (non-critical), pump covers. | KX-CNAF HD |
| Flexible Graphite | -400°F to 1200°F (-240°C to 650°C) Inert / -400°F to 850°F (-240°C to 454°C) Oxidizing | Up to 2500 PSI (172 bar) | Excellent for hot oils, steam, hydrocarbons, and many chemicals. Unsuitable for strong oxidizers. | Very Good | High-temperature heat exchangers, turbine systems, exhaust flanges, refinery applications. | KX-Graphite Ultra |
| Nitrile Rubber (NBR) | -40°F to 250°F (-40°C to 121°C) | Up to 1000 PSI (69 bar) | Excellent resistance to oils, fuels, aliphatic hydrocarbons, water, and glycols. | Fair to Good | Automotive, hydraulic systems, fuel handling, general-purpose oil seals. | KX-Nitrile 70 |
| Silicone Rubber | -80°F to 450°F (-62°C to 232°C) | Up to 800 PSI (55 bar) | Good for hot air, ozone, and weathering. Fair chemical resistance; poor against fuels and solvents. | Fair | Appliance, lighting, aerospace, food-grade applications (specific grades), static seals. | KX-Silicone HT |
| EPDM Rubber | -60°F to 300°F (-51°C to 149°C) | Up to 800 PSI (55 bar) | Superior resistance to hot water, steam, ozone, weathering, alkalis, and mild acids. | Good | Plumbing, HVAC, cooling systems, automotive cooling circuits, outdoor seals. | KX-EPDM Weatherseal |
| Stainless Steel Jacketed (with filler) | -450°F to 1500°F (-268°C to 816°C) *Depends on filler | Very High (limited by flange rating) | The metal jacket protects the soft filler (e.g., graphite, PTFE) from corrosive/erosive media. | Excellent | High-pressure/temperature steam, heat exchangers, aggressive chemical services in pipelines. | KX-JacketSeal |
Gasket Materials FAQ
Q: What is the most important factor when choosing a gasket material?
A: The most critical factor is comprehensive media compatibility. The gasket material must be chemically resistant to all fluids, gases, and process conditions it will encounter. A material that fails due to chemical attack can lead to rapid leakage, safety hazards, and unplanned downtime. Always cross-reference chemical resistance charts and consult with specialists like Kaxite Seals for confirmation.
Q: Can I use a rubber gasket for a high-temperature application?
A: Generally, standard elastomers like NBR or EPDM are unsuitable for sustained high temperatures above 250-300°F (121-149°C). They will harden, crack, and lose sealing force (high compression set). For temperatures exceeding this, consider materials like Flexible Graphite (KX-Graphite Ultra) or ePTFE (KX-ePTFE Pro), which are engineered for thermal stability.
Q: What does "Compression Set" mean, and why is it important?
A: Compression set is a measurement of a material's permanent deformation after being compressed for a set time at a specific temperature. A low compression set percentage (e.g., 15%) means the material springs back well, maintaining bolt load and seal integrity. A high percentage (e.g., 60%) indicates the material has taken a permanent "set," leading to clamp load loss and potential leakage. It's crucial for long-term, maintenance-free service.
Q: How do I choose between ePTFE and Compressed Non-Asbestos sheets?
A: ePTFE is superior for extreme chemical resistance, wide temperature ranges, and creep resistance. It's often used in critical or aggressive service. CNAF sheets are a robust, cost-effective solution for general industrial applications involving water, steam, oils, and moderate chemicals. If budget allows and conditions are harsh, ePTFE is the premium choice. For standard utility services, CNAF is highly reliable.
Q: Why does my graphite gasket require a controlled torque procedure?
A: Pure flexible graphite is a soft, malleable material. Under-torquing can result in insufficient initial sealing. Over-torquing can cause the material to yield excessively, flow out of the flange, or even be crushed, leading to failure. Following a controlled, multi-pass bolt tightening procedure ensures the graphite conforms to flange imperfections and achieves an optimal, uniform seal without damage.
Q: What certifications do Kaxite Seals materials hold?
A: Kaxite Seals materials are manufactured to meet and exceed international standards. Our product lines hold relevant certifications such as FDA CFR 177.1550 for indirect food contact (specific grades), NSF 61 for drinking water components, ATEX/IECEx for explosive atmospheres (where applicable), and are compliant with industry standards like ASTM F36, ASME B16.21, and DIN specifications. Certificates are available upon request.
Q: Can you provide custom-shaped gaskets, or only sheet material?
A: Kaxite Seals provides complete sealing solutions. We supply both raw sheet, roll, and coil stock for in-house fabrication and offer full-service precision cutting. We can manufacture custom gaskets through die-cutting, water-jet cutting, or CNC machining from any of our materials, ensuring precise dimensions, clean edges, and optimal performance for your specific flange or housing.
Advanced Material Considerations
Beyond the standard sheet materials, Kaxite Seals develops specialized composite and engineered solutions for unique challenges:
- PTFE Envelope Gaskets: Feature a corrosion-resistant PTFE envelope filled with a resilient material, ideal for highly corrosive services.
- Spiral Wound Gaskets: Combine alternating plies of metal windings and filler material (graphite, PTFE) for high-pressure/temperature flanged connections.
- Kamprofile Gaskets: A metal core with serrated faces filled with a soft filler, offering excellent sealing with lower bolt load requirements.
- Electrically Conductive Materials: Special graphite or compound-based materials designed for applications requiring static dissipation or electrical grounding across the joint.
The engineering team at Kaxite Seals is equipped to analyze your application parameters—including flange type, surface finish, bolt load, and cyclic conditions—to recommend the optimal, most cost-effective gasket material solution. Proper material selection is not an expense; it is an investment in system reliability.
