MIL-DTL-25988 Fluorosilicone

MIL-DTL-25988 fluorosilicone from ElastaPro meets the requirements of a U.S. military detail specification for a fluorosilicone rubber (FVMQ) that resists fuels, oils, and high temperatures. MIL-DTL-2598 superseded MIL-R-25988 and was in turn superseded by AMSR25988, an SAE International standard.

MIL-DTL-25988 fluorosilicones are categorized by types, classes, and grades. For example, a MIL-DTL-25988 Type 2 Class 1 Grade 60 material is a general-purpose, 60-durometer fluorosilicone rubber intended for molded parts, sheets, or extrusions. ElastaPro offers both solid fluorosilicone sheet and uncured fluorosilicone compounds.

Types

This specification defines two main types of military silicone based on the intended application.

Type 1: Materials for O-rings (compression seals).
Type 2: Materials for molded parts (other than O-rings), sheets, strips, and extruded shapes.

Classes

Within each Type, there are two classes based on material strength and purpose.

Class 1: General-purpose fluorosilicones.
Class 2: Higher-strength fluorosilicones for more demanding general-purpose applications.

Grades

Grades are defined by the material’s durometer (hardness) on the Shore A scale. The specific grades correspond to common durometer measurements:

Grade 40 (40 durometer)
Grade 50 (50 durometer)
Grade 60 (60 durometer)
Grade 70 (70 durometer)
Grade 75 (75 durometer)
Grade 80 (80 durometer)

Applications

Applications for MIL-DTL-25988 fluorosilicone include seals, O-rings, and gaskets used in aircraft fuel systems to prevent leaks and resist exposure to jet fuel, engine grease, and other harsh chemicals. These materials are also used in hydraulic equipment, industrial machinery, and chemical processing systems where there are solvents or other harsh chemicals.