Product Partners

PRC-DeSoto Products

Aircraft fuel tank, fuselage, windshield, conductive and specialty sealants Industrial sealants and adhesives

Semco® Packaging and Application Systems

Innovative, clean, safe, and accurate packaging and dispensing solutions for single-and multi-component adhesives, sealants, encapsulants, coatings and lubricants

RPM Technology

Products for the removal of polysulfide (fuel tank) sealants and silicone sealants

eOx Cleaners

Aqueous based aircraft and industrial cleaners

Sealant Removal Wipes

Water wetted wipes for the removal of uncured sealants and adhesives

Glue Dots

Removable adhesive dots in a convenient dispenser box

Class C Sealant Application Time

The Application Time or Standard Work Life is the number after the Class letter. For Class A and B, 1/2 equals 1/2 hour application time and 2 equals 2 hour application time.
For Class C the Application and Assembly Time conform to industry and manufacture's specifications.

Class C Application Time

Specification Class Designation Applicaton Time Squeeze-out/Assembly time Standard Cure @ 77°F
BMS 5-95 C-20 12 hours 20 hours 3 weeks
C-80 24 hours 48 hours 6 weeks
C-168 48 hours 168 hours 10 weeks
C-336 96 hours 336 hours 20 weeks
MIL-PRF-81733 Type IV-4 4 hours 8 hours Not Applicable
Type IV-12 12 hours 24 hours Not Applicable
Type IV-24 24 hours 48 hours Not Applicable
Type IV-40 40 hours 120 hours Not Applicable
Type IV-48 48 hours 168 hours Not Applicable

Application Time

The length of time, after mixing, or the end of the thaw for PMF, the sealant remains suitable for application to the substrate. Since temperature and humidity can greatly affect this, stated application time is generally established at 77°F (25°C) and 50% relative humidity.

Tack-Free-Time (TFT)

The length of time for a sealant to cure to a state where polyethylene film, applied with light pressure to the sealant’s surface, can be cleanly removed. A TFT condition generally occurs well after the Assembly time for a given sealant.

Cure Rate

The length of time it takes for a sealant to cure to a certain minimum hardness as determined by the procuring specification. This is not the final cure hardness for the sealant, but indicates the time needed at standard conditions to reach a serviceable state.

Special notes for Class C sealants

Assembly Time: The maximum length of time, after mix or thaw of PMF that a sealant remains suitable to assembly parts, including the final torquing of fasteners, to assure proper sealing. The term is used interchangeable with Squeeze-Out Life. The stated Assembly Time will be longer than the sealant Application Time, and is determined at standard temperature and humidity as defined by the procuring specification. Apparent or actual Assembly time will vary with ambient conditions.