SSP-389 is a 70-durometer, peroxide-catalyzed, heat-cured silicone that meets AMS 3304 and AA 59588, Class 2A and 2B, Grade 70 requirements.


AMS 3304 Silicone Rubber, 70 Durometer

SSP-389 is a 70-durometer (Shore A) silicone elastomer that uses a Varox-peroxide and dicumyl-peroxide catalyst system. This heat-cured silicone meets the requirements of both AMS 3304 and AA 59588, Class 2A and 2B, Grade 70. Because AA 59588 compounds require significant testing, there is a $500 minimum order amount. Small-quantity orders may be subject to certification charges.  

AMS 3304 Specification

The AMS 3304 specification covers silicone rubber in the form of sheets, strips, tubing, extrusions, and molded shapes. SAE International, a professional association and standards-developing organization, defines Aerospace Material Specifications (AMS) like AMS 3304.

AMS 3304 Shelf Life

The shelf life for uncatalyzed SSP-389 is indefinite, but this military and aerospace silicone may need freshening after 1 to 2 years. When catalyzed, the shelf life is 6 months. Cold storage will extend the shelf life for this general-purpose silicone rubber.

AMS 3304 Spec and SSP-389 Test Data

The AMS 3304 spec is available from SAE International. The table below shows test data for SSP-389 that was generated with the DBPH catalyst system.  


Typical Values

Shore A (65 - 75 range)


Tensile Strength (650 psi minimum)

1100 psi

Elongation % (125 minimum)


Tear B (25 ppi min)

80 ppi

Specific Gravity


Other tests performed in accordance with AMS 3304 and AA 59588 2A and 2B, Grade 70 specifications include:

  • 70 hours compression set
  • Brittle point
  • Torsional stiffness
  • Heat aging change
  • Volume change in water
  • IRM901 oil immersion change

AMS 3304 Data Sheet

Download the SSP-389 data sheet and compare this PDF against the AMS 3304 specs from SAE International. 

Contact SSP to request a quote, or for additional information about this silicone rubber.