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MIL-PRF-81733

MIL-PRF-81733 is a military specification that defines the performance requirements for high-performance sealing and coating compounds designed to protect metal components on weapons and aircraft systems from corrosion. These accelerated, room temperature curing synthetic rubber compounds form a strong and flexible barrier that is required within aerospace applications. Most commonly used for sealing of fuel tanks and other aircraft components to protect against the harsh environments and chemicals typically encountered in service.

MIL-PRF-81733 Product List

PPG PS870 B-1/2 Corrosion Inhibitive Sealant
PPG PS870 B-1/2 Corrosion Inhibitive Sealant
Silmid P/N: 
VAR0000435
In Stock
From £48.45 excl VAT
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PPG PS870 B-2 Corrosion Inhibitive Sealant
PPG PS870 B-2 Corrosion Inhibitive Sealant
Silmid P/N: 
VAR0000436
In Stock
From £48.45 excl VAT
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PPG PS870 C-12 Corrosion Inhibitive Sealant
PPG PS870 C-12 Corrosion Inhibitive Sealant
Silmid P/N: 
VAR0000438
No Stock - Standard lead time 73 business days
From £82.83 excl VAT
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PPG PS870 A-2 Corrosion Inhibitive Sealant
PPG PS870 A-2 Corrosion Inhibitive Sealant
Silmid P/N: 
VAR0000434
In Stock
From £66.24 excl VAT
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PPG PS870 C-24 Corrosion Inhibitive Sealant 6Floz Semkit *MIL-PRF-81733D Type IV-24 Class 1 Grade A
PPG PS870 C-24 Corrosion Inhibitive Sealant 6Floz Semkit *MIL-PRF-81733D Type IV-24 Class 1 Grade A
Silmid P/N: 
P870C24100
No Stock - Standard lead time 101 business days
£167.52 excl VAT
PPG PS870 A-1/2 Corrosion Inhibitive Sealant
PPG PS870 A-1/2 Corrosion Inhibitive Sealant
Silmid P/N: 
VAR0000433
In Stock
From £66.24 excl VAT
View Details

Properties

The polysulfide sealing compounds specified in MIL-PRF-81733 have several essential properties.

Adhesion: Strong adhesion to various substrates, including metals and composites.

Flexibility: Remains flexible across a wide temperature range, crucial for maintaining seals in varying conditions.

Chemical Resistance: Resistant to fuels, oils, hydraulic fluids, and other chemicals commonly encountered in aerospace environments.

Curing: Cures at room temperature to form a durable and resilient seal.

Applications

Widely used in aerospace applications. Here are a few examples:

  • Sealing fuel tanks and fuel lines
  • Insulating pressurised cabins
  • Sealing joints and seams in aircraft structures
  • General-purpose sealing applications in harsh environments

Classes

Class 1:

  • Effective from -65°F to +250°F (-54°C to +121°C)
  • Used for sealing applications requiring fuel resistance and low-temperature flexibility.

Class 2:

  • Effective from -80°F to +320°F (-62°C to +160°C)
  • Designed for high-temperature applications and exposure to aircraft fluids.

PR-1770 packaging

Types

There are four main types of MIL-PRF-81733 sealant:

Type I: Typically used for integral fuel tanks and pressurized cabins.  
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Type II: Offers broader application due to its resistance to a wider range of chemicals.
Type III: Specifically designed for use with certain types of fuels.
Type IV: Used in specific applications requiring high temperature resistance.

Versions

The most recent version of the spec is MIL-PRF-81733D, where MIL = Military Specification, PRF = Performance Requirements, 81733 = Unique identification number, D = Revision version. This version was created in May 1998, Superseding MIL-S-81733C.

MIL-S-81733C was a previous version of the spec, where S = Sealant. MIL-S-81733C was established in March 1980, with a further amendment in February 1988.