ZZ-R-765 Class 2A, 2B, 3A, 3B
What Is ZZ-R-765 Class 2A, 2B, 3A, 3B?
ZZ-R-765 is a military silicone rubber specification long used in aerospace, defense, and other high-performance applications. This designation has been superseded by A-A-59588, which is the current commercial item description for these silicone rubber classes and grades.
Even so, ZZ-R-765 is still widely referenced on legacy drawings, product requests, and material callouts.
ZZ-R-765 Class 2A, 2B, 3A, and 3B identify silicone rubber materials selected for different performance requirements, including high temperature resistance, low temperature flexibility, low compression set, tear resistance, and flex-fatigue resistance.
These classes are commonly specified for custom gaskets, seals, O-rings, extruded profiles, sponge components, sheet materials, and other fabricated silicone rubber parts.
These classes are especially relevant for aerospace, military, and defense applications where silicone rubber parts must match the required class, grade, temperature profile, and performance expectations. Elastostar also offers customized gaskets and can reverse engineer silicone rubber components from samples, drawings, or application needs.
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Key Material Features Of ZZ-R-765 Classes
Military Silicone Specification
ZZ-R-765 remains a recognized silicone rubber specification in aerospace and defense markets, even though A-A-59588 is the current reference.
Defined Class Based Performance
Class 2A, 2B, 3A, and 3B identify different material profiles based on heat resistance, low temperature performance, compression set, tear resistance, and flex-fatigue resistance.
Suitable For Multiple Product Forms
These classes can be supplied in sheet, strip, gasket, seal, extrusion, sponge, and fabricated part form.
Relevant For Demanding Service Conditions
These materials are commonly selected where sealing reliability, environmental resistance, and long-term durability are important.
Product Applications For ZZ-R-765 Silicone Rubber
ZZ-R-765 Class 2A, 2B, 3A, and 3B silicone rubber materials are suitable for a wide range of custom rubber products used in demanding aerospace, defense, and industrial environments. These classes are commonly used for:
Silicone Gaskets: For sealing performance in high and low temperature environments.
Customized Gaskets: For aerospace, military, defense, industrial, food grade, and specialty applications where the gasket must match the required material grade, size, shape, and performance need.
Silicone Seals: For enclosure sealing, closure sealing, and environmental protection.
O-Rings: For standard and custom sealing requirements where durability and material consistency matter.
- Extruded Profiles: For custom shapes used in sealing, edge protection, and gap coverage.
- Silicone Sponge Parts: For cushioning, insulation, and lightweight sealing applications.
- Sheet And Strip Materials: For custom cut parts, lining, and sealing requirements.
- Molded Silicone Parts: For application specific components requiring dependable material performance.
These product forms are selected where temperature resistance, sealing performance, flexibility, and long-term material reliability are important.
Temperature Performance By Class
The service temperature range depends on the class selected.
Class 2A: Approximately -80°F to 425°F.
Class 2B: Approximately -80°F to 425°F.
Class 3A: Approximately -103°F to 400°F.
Class 3B: Approximately -95°F to 400°F.
These ranges are widely used in A-A-59588 cross-reference guidance for ZZ-R-765 materials.
Available Grades By Class
Under the A-A-59588 system that superseded ZZ-R-765, these classes are commonly associated with the following grade ranges:
Class 2A: Grades 25, 40, 50, 60, 70, 80.
Class 2B: Grades 40, 50, 60, 70, 80.
Class 3A: Grades 30, 50, 60.
Class 3B: Grades 30, 50, 60, 70, 80.
Industry references note that A-A-59588 removed Class 2B Grade 25, which is one reason it is important to certify to the correct current standard.
ZZ-R-765 Specification Overview
| Category : | rgba(248, 250, 250, 1) |
| Original Specification | ZZ-R-765 |
| Current Reference | rgba(248, 250, 250, 1) |
| Material Type | Silicone rubber |
| Relevant Classes | Relevant Classes |
| Industry Use | Aerospace, defense, and demanding industrial applications |
| Noted For | Noted For |
Performance Characteristics Of ZZ-R-765 Silicone Rubber
Depending on the selected compound and project requirement, silicone rubber components can also be developed for food grade, medical, industrial, and specialty applications.
Food grade silicone projects may require FDA 21 CFR 177.2600, NSF 51 compounds, metal detectable silicone, or X-ray detectable silicone. Medical and pharmaceutical applications may require USP Class VI Section 87 and 88 materials.
ZZ-R-765 Class 2A, 2B, 3A, and 3B silicone rubber materials are commonly selected for characteristics such as:
high temperature resistance.
low temperature flexibility.
low compression set.
tear resistance.
flex-fatigue resistance.
long term sealing performance.
durability in demanding environments.
These characteristics make these classes relevant for aerospace and defense silicone rubber components where both environmental resistance and physical performance are important
Class Details For ZZ-R-765 2A, 2B, 3A, And 3B
Class 2A: Intended for applications where strong high-temperature resistance is required, with low-temperature resistance to about -80°F.
Class 2B: Similar to Class 2A, but also identified for low compression set.
Class 3A: Intended for applications requiring extreme low-temperature resistance to about -103°F, along with tear resistance and flexing performance. It also offers high-temperature resistance to about 400°F.
- Class 3B: Used where tear resistance and flex-fatigue resistance are important, with temperature performance to about -95°F and 400°F
- Current Reference: ZZ-R-765 is still widely referenced in the market, but A-A-59588 is the current governing commercial item description.
Related Aerospace And Military Specifications
A-A-59588: The current commercial item description that superseded ZZ-R-765.
AS9100D: Relevant when silicone rubber products are manufactured under an aerospace quality management system.
AMS Specifications: Certain aerospace applications may also reference AMS material requirements depending on the product, hardness, and end use.
Related Industry Compliance Options
ZZ-R-765 and A-A-59588 are important for aerospace, military, and defense silicone rubber requirements. Other industries may need different quality or material standards based on the end use.
Aerospace: AS9100D, ZZ-R-765, and A-A-59588.
Pharma And Medical: USP Class VI Section 87 and 88.
Food: FDA 21 CFR 177.2600, NSF 51, solid FDA grade white silicone, metal detectable silicone, and X-ray detectable silicone.
- Automotive: IATF quality management.
- General Industrial: ISO 9000 quality management.
- Conductive And Reinforced Grades: Solid silicone electrically conductive grade and solid silicone fiberglass reinforced grade may suit specialty silicone applications.
- Flame Resistant Applications: UL 94 V-0 and UL 94 V-0 flame retardant silicone sponge.
Why ZZ-R-765 Class 2A, 2B, 3A, 3B Matters To Aerospace And Defense Buyers
For aerospace and defense buyers, these class designations provide a practical framework for selecting the right silicone rubber material for the application.They help identify whether the material is better suited for high heat, low compression set, extreme low temperature, or improved tear and flex performance.
This is especially important in aerospace and defense applications, where the selected material must match the operating environment as well as the performance demands of the finished component.
Why Choose Elastostar Rubber Corporation For ZZ-R-765 Silicone Rubber Requirements?
Elastostar Rubber Corporation is a custom manufacturer of ZZ-R-765 silicone rubber , silicone seals, and rubber seals for demanding industries where quality, consistency, and performance matter.
We can also reverse engineer silicone rubber parts and manufacture customized gaskets based on samples, drawings, or application requirements. This helps buyers convert the correct ZZ-R-765 or A-A-59588 material into a finished part that fits the required use.
With a large manufacturing facility, custom manufacturing capabilities, and Made in USA production, the company supplies dependable ZZ-R-765 silicone rubber solutions for aerospace, defense, and military specification requirements.
For aerospace, defense, and industrial buyers, selecting the right silicone class is only part of the decision. Converting the right ZZ-R-765 silicone rubber material into a dependable finished part with the required form, fit, and performance is just as important.
