Specification Grade Silicones

AMS-R-25988 Fluorosilicone Sheeting & Uncured Compounds

ElastaPro manufactures premium AMS-R-25988 fluorosilicone sheeting and uncured compounds engineered for demanding aerospace, military, and industrial applications that require resistance to aggressive fuels, synthetic oils, fluids, and harsh chemicals. Published by SAE International, AMS-R-25988 (formerly MIL-R-25988) defines strict physical, mechanical, and fluid-immersion thresholds for fluorosilicone elastomers (FVMQ).

Fluorosilicone combines the wide operating temperature performance of standard silicone with the superior chemical and solvent resistance of fluorocarbons. This makes AMS-R-25988 fluorosilicone the preferred elastomer for dynamic airframe fuel systems, aircraft engine nacelles, and military defense equipment. Every batch is Made in the USA at our Santa Fe Springs, California facility under an AS9100D and ISO 9001:2015 certified quality management system and supplied with a complete Certificate of Analysis (COA).

Need AMS-R-25988 Fluorosilicone Sheeting or Slit Rolls?

We supply continuous roll stock, pre-cut solid sheets, and custom uncured compounds across multiple classifications with low minimum order quantities and fast turnarounds.

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AMS-R-25988 Specification Matrix & Material Types

The AMS-R-25988 specification categorizes fluorosilicone materials into distinct types, classes, and durometer grades (Shore A) based on product form and application requirements:

Material Type Product Form / Description Available Durometer Grades (Shore A) Primary Performance Focus
Type I O-rings and Molded Shapes Class 1 (40, 60, 80) & Class 2 (50, 70) Precision molded seals with high fluid resistance
Type II Sheet, Strip, and Extruded Shapes Class 1 (40, 60, 80) & Class 2 (50, 70) Flat die-cut gaskets, sealing strips, and continuous roll stock
Type IV High-Tear-Strength Fluorosilicone Class 1 (30, 50, 70) Dynamic flex applications requiring tear and flex-fatigue resistance

AMS-R-25988 Fluorosilicones from ElastaPro

ElastaPro makes the following types of AMS-R-25988 fluorosilicones.

  • AMS-R-25988B Type II, Class 1, Grade 40
  • AMS-R-25988 Type II, Class 1, Grade 50
  • AMS-R-25988B Type II, Class 1, Grade 60
  • AMS-R-25988B Type II, Class 1, Grade 70

These materials are available as solid sheeting and uncured compound.

Note: An independent testing laboratory has requalified these materials. ElastaPro will send the full requalification test reports to qualified buyers who request them.

Key Performance Advantages

  • Unmatched Chemical & Solvent Resistance: Resists degradation from jet fuel (JP-4, JP-8, Jet A-1), hydraulic fluids (Skydrol), automotive fuels, synthetic lubricants, and aggressive solvents.
  • Broad Operating Temperature Range: Retains flexibility and sealing force across extreme thermal profiles ranging from sub-zero conditions down to -80°F (-62°C) up to elevated temperatures of +350°F to +400°F (+177°C to +204°C).
  • Low Compression Set: Maintains continuous sealing force under persistent bolt load, preventing fluid seepage in flange connections over extended service cycles.
  • Precision Converting Ready: Easily die-cut or waterjet cut into custom aircraft fuel gaskets, or supplied with factory-applied Pressure Sensitive Adhesive (PSA) backings.

Target Industry Applications

  • Aircraft Fuel Systems: Fuel tank access door seals, fuel line gaskets, pump diaphragms, and metering valve seals.
  • Aerospace Engine Nacelles: Environmental seals and thermal barriers exposed to jet fuel vapors and synthetic engine oils.
  • Automotive & Defense Fuel Lines: High-performance fuel system seals for military ground transport vehicles and racecraft.
  • Chemical Processing: Fluid seals and gaskets operating in aggressive solvent vapor environments.

Note: Specification grade silicones from ElastaPro include many other types of aerospace silicones and military silicones, including other types of fluorosilicones (e.g., AMS 3325 through AMS 3331).

Frequently Asked Questions About AMS-R-25988 Fluorosilicone

What is AMS-R-25988 fluorosilicone, and how does it differ from standard silicone?

AMS-R-25988 is an aerospace specification defining fluorosilicone rubber (FVMQ). While standard silicone offers excellent temperature tolerance, it swells and degrades rapidly when exposed to fuels, oils, and solvents. Fluorosilicone incorporates trifluoropropyl side groups into the polymer chain, giving it exceptional resistance to jet fuel, hydraulic fluids, and chemicals while retaining silicone’s wide temperature range.

What is the relationship between AMS-R-25988 and MIL-R-25988?

AMS-R-25988 is the modern SAE specification that directly superseded the legacy military specification MIL-R-25988. Engineering drawings or defense callouts referencing MIL-R-25988 can be satisfied directly using corresponding AMS-R-25988 material types and classes.

What is the difference between Class 1 and Class 2 in AMS-R-25988?

Class 1 fluorosilicone is formulated for general-purpose oil and fuel resistance with balanced physical properties. Class 2 fluorosilicone is specifically compounded to deliver lower compression set performance, making it the preferred choice for static flange gaskets where long-term sealing pressure must be maintained under fluid immersion.

Can ElastaPro supply spec-grade fluorosilicone with adhesive backing?

Yes. ElastaPro AMS-R-25988 fluorosilicone sheeting can be supplied with factory-applied pressure-sensitive adhesive (PSA) backings to simplify gasket installation. Options include chemical-resistant acrylic adhesives or high-temperature silicone adhesives protected by a peel-off liner.