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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. MIL-PRF-81733 sealant is an accelerated, room temperature curing synthetic rubber compound that forms a strong and flexible barrier required in aerospace applications. It is most commonly used for sealing fuel tanks and other aircraft components to protect against the harsh environments and chemicals typically encountered in service.

The products listed below are qualified MIL-PRF-81733 sealants designed for aerospace and defence applications. Each option meets the MIL-PRF-81733 specification and is available in a range of classes, work lives, and pack sizes to suit different sealing tasks, from fuel tank repairs to fuselage joints. Selecting a MIL-PRF-81733 sealant from this range helps ensure compliance with military specifications while maintaining reliable corrosion protection in service.

MIL-PRF-81733 Product List

PPG PS870 C-24 Corrosion Inhibitive Sealant 6oz Semkit *MIL-PRF-81733D Type IV-24 Class 1 Grade A
PPG PS870 C-24 Corrosion Inhibitive Sealant 6oz Semkit *MIL-PRF-81733D Type IV-24 Class 1 Grade A
Silmid P/N: 
P870C24100
No Stock - Standard lead time 103 business days
£167.52 excl VAT
PPG PS870 A-1/2 Corrosion Inhibitive Sealant 1USP Kit *MIL-PRF-81733D Type I-1/2 Grade A
PPG PS870 A-1/2 Corrosion Inhibitive Sealant 1USP Kit *MIL-PRF-81733D Type I-1/2 Grade A
Silmid P/N: 
PS870AAUSP
No Stock - Standard lead time 103 business days
£296.98 excl VAT
PPG PS870 A-2 Corrosion Inhibitive Sealant 1USP Kit *MIL-PRF-81733D Type I-2 Grade A
PPG PS870 A-2 Corrosion Inhibitive Sealant 1USP Kit *MIL-PRF-81733D Type I-2 Grade A
Silmid P/N: 
PS870AB1UP
No Stock - Standard lead time 103 business days
£296.98 excl VAT
PPG PS870 A-2 Corrosion Inhibitive Sealant 6oz Semkit *MIL-PRF-81733D Type I-2 Grade A
PPG PS870 A-2 Corrosion Inhibitive Sealant 6oz Semkit *MIL-PRF-81733D Type I-2 Grade A
Silmid P/N: 
PS870AB6FO
No Stock - Standard lead time 103 business days
£129.13 excl VAT
PPG PS870 B-1/2 Corrosion Inhibitive Sealant 500ml Kit *MIL-PRF-81733D Type II-1/2 Class 1 Grade A
PPG PS870 B-1/2 Corrosion Inhibitive Sealant 500ml Kit *MIL-PRF-81733D Type II-1/2 Class 1 Grade A
Silmid P/N: 
PS870BA654
On Order - 3 available in 6 days
£188.20 excl VAT
PPG PS870 B-1/2 Corrosion Inhibitive Sealant 105ml Semkit *MIL-PRF-81733D Type II-1/2 Class 1 Grade A
PPG PS870 B-1/2 Corrosion Inhibitive Sealant 105ml Semkit *MIL-PRF-81733D Type II-1/2 Class 1 Grade A
Silmid P/N: 
PS870BA6FL
No Stock - Standard lead time 47 business days
£79.76 excl VAT
PPG PS870 B-2 Corrosion Inhibitive Sealant 500ml Kit *MIL-PRF-81733D Type II-2 Class 1 Grade A
PPG PS870 B-2 Corrosion Inhibitive Sealant 500ml Kit *MIL-PRF-81733D Type II-2 Class 1 Grade A
Silmid P/N: 
PS870B2USP
No Stock - Standard lead time 82 business days
£188.20 excl VAT
PPG PS870 B-2 Corrosion Inhibitive Sealant 105ml Semkit *MIL-PRF-81733D Type II-2 Class 1 Grade A
PPG PS870 B-2 Corrosion Inhibitive Sealant 105ml Semkit *MIL-PRF-81733D Type II-2 Class 1 Grade A
Silmid P/N: 
PS870BB6OZ
No Stock - Standard lead time 103 business days
£79.76 excl VAT
PPG PS870 C-12 Corrosion Inhibitive Sealant 500ml Kit *MIL-PRF-81733D Type IV-12 Class 1 Grade A
PPG PS870 C-12 Corrosion Inhibitive Sealant 500ml Kit *MIL-PRF-81733D Type IV-12 Class 1 Grade A
Silmid P/N: 
P870C12050
On Order - 20 available in 6 days
£297.87 excl VAT
PPG PS870 C-12 Corrosion Inhibitive Sealant 105ml Semkit *MIL-PRF-81733D Type IV-12 Class 1 Grade A
PPG PS870 C-12 Corrosion Inhibitive Sealant 105ml Semkit *MIL-PRF-81733D Type IV-12 Class 1 Grade A
Silmid P/N: 
P870C12100
On Order - 135 available in 6 days
£114.02 excl VAT
3M AC-735 B-1/2 Aerospace Sealant 6oz (3.5oz Fill) Injection Kit (New Formulation) *MIL-PRF-81733
3M AC-735 B-1/2 Aerospace Sealant 6oz (3.5oz Fill) Injection Kit (New Formulation) *MIL-PRF-81733
Silmid P/N: 
P1400476
On Order - 96 available in 124 days
£103.02 excl VAT
3M AC-735 B-2 Aerospace Sealant 6oz (3.5oz Fill) Injection Kit (New Formulation) *MIL-PRF-81733
3M AC-735 B-2 Aerospace Sealant 6oz (3.5oz Fill) Injection Kit (New Formulation) *MIL-PRF-81733
Silmid P/N: 
P1400477
On Order - 96 available in 124 days
£105.70 excl VAT

MIL-PRF-81733 Sealant Properties

The polysulfide sealing compounds specified in MIL-PRF-81733 have several essential properties. These MIL-PRF-81733 sealants are formulated for demanding aerospace environments where long lasting protection is critical.

  • 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.

MIL-PRF-81733 Sealant Applications

MIL-PRF-81733 sealant is 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

MIL-PRF-81733 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 of MIL-PRF-81733 Sealant

There are four main types of MIL-PRF-81733 sealant, each MIL-PRF-81733 sealant type has a distinct application profile.

Type I - for brush or dip application.

Type II - for extrusion application with a gun or spatula.

Type III - for spray gun applications.

Type IV - for fating surface applications with a gun or spatula.

MIL-PRF-81733 Versions and Revisions

Military specifications (MIL Specs) are formal standards used by defence and aerospace organisations to ensure that materials and products meet consistent performance, safety, and quality requirements. When a sealant meets a MIL Spec such as MIL-PRF-81733, it has been tested against defined criteria so engineers and procurement teams can specify it with confidence.

The most recent version of the MIL-PRF-81733 sealant specification 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.

MIL-PRF-81733 FAQs

Which products meet MIL-PRF-81733 requirements?

The MIL-PRF-81733 Product List on this page includes sealants that are qualified to the MIL-PRF-81733 specification. These MIL-PRF-81733 sealants are available in different classes, work lives, and pack sizes so that engineers and procurement teams can select a product that matches the required application method, service temperature range, and fuel or fluid exposure.

What are MIL Specs and why are they important?

Military specifications, often called MIL Specs, are formal standards used to ensure that materials and products meet consistent requirements for performance, safety, and quality. When a sealant meets a MIL Spec such as MIL-PRF-81733, it has been tested against defined performance criteria so that aerospace and defence organisations can specify it with confidence in demanding environments.

Should rivets be installed wet with MIL-PRF-81733 sealant?

In many aerospace applications, rivets are installed wet with a MIL-PRF-81733 sealant to help seal joints and provide additional protection against corrosion. However, installation practices can vary by aircraft type, structural location, and OEM requirements. Always refer to the applicable aircraft maintenance manual or engineering specification before deciding whether to install rivets wet with MIL-PRF-81733 sealant.