PPG PR1428B-1/2 (1-ea-S654)

PR-1428 Class B Access Door Sealant

Overview

PR-1428 Class B is a two-component, manganese dioxide-cured polysulfide sealant developed by PPG Aerospace (PRC-DeSoto) for removable sealing applications on aircraft. Designed as a low-adhesion sealant, it is primarily used for sealing access doors, fabricating form-in-place (FIP) gaskets, and protecting electrical wiring and equipment from fuel, moisture, dirt and contaminants. The low-sag, thixotropic formulation cures at room temperature to form a durable yet removable seal across a wide range of common aerospace substrates.

Key Technical Specs

• Product Type: Two-component manganese dioxide-cured polysulfide sealant
• Class: Class B
• Colour (Mixed): Dark Red
• Mix Ratio (by Weight): 10 Parts A : 100 Parts B
• Application Method: Extrusion gun or spatula
• Service Temperature Range: -54°C to +121°C (-65°F to +250°F)
• Intermittent Temperature Exposure: Up to +135°C (+275°F)
• Specific Gravity (Cured): 1.50
• Non-Volatile Content: 97%
• Ultimate Hardness: 50 Shore A
• Application Life: 30 minutes (B-1/2), 2 hours (B-2)
• Storage Life: Minimum 12 months below 27°C (80°F)

Approvals & Specifications

• MIL-S-8784 Class B
• Surface preparation references SAE AIR 4069
• Cleaning cloths should conform to AMS 3819

Typical Applications

• Aircraft access door sealing
• Form-in-place (FIP) gasket fabrication
• Protection of aircraft electrical wiring
• Protection of electrical terminals and connectors
• Environmental sealing of aircraft equipment
• Moisture and fuel barrier applications
• OEM aircraft production and MRO maintenance

Key Features & Benefits

• Low-adhesion formulation allows easy removal during maintenance.
• Excellent protection against fuel, moisture, dirt and contaminants.
• Room-temperature curing simplifies application.
• Low-sag thixotropic consistency prevents sealant slump.
• Excellent flexibility at temperatures down to -54°C.
• Resistant to aviation fuels and hydrocarbon exposure.
• Protects electrical systems against contamination and short circuits.
• Compatible with a wide variety of common aircraft substrates.

Application Guidelines

• Clean substrates immediately before sealing using approved aerospace solvents.
• Use fresh lint-free cloths conforming to AMS 3819 during cleaning.
• Dry the surface with a second clean cloth before solvent evaporation.
• Mix Part A and Part B separately before combining.
• Thoroughly mix both components until a uniform colour is achieved.
• Determine adhesion performance on production substrates before full application.
• Follow SAE AIR 4069 recommendations for optimum surface preparation.

Compatibility & Limitations

• Designed for removable sealing rather than permanent structural bonding.
• Compatible with common aircraft metallic and primed substrates.
• Suitable for access doors, removable panels and electrical protection.
• Substrate-specific adhesion should be validated before production use.
• Not intended for high-strength adhesive applications.

Packaging & Procurement

• Supplied in two-part kits
• Available in Semco® cartridges
• Minimum shelf life: 12 months
• Store below 27°C (80°F) in original unopened containers

Why This Product is Chosen for AOG / MRO

• Provides reliable sealing while remaining removable for future maintenance.
• Protects electrical systems from harsh operating environments.
• Excellent resistance to aviation fuels and moisture.
• Easy application with minimal slump.
• Ideal for repeated access panel removal and servicing.

Practical Suggestions for Your Team (AOG Mindset)

• Ensure surfaces are completely clean before applying the sealant.
• Mix thoroughly to avoid uncured material within the seal.
• Select the appropriate application life based on repair size.
• Always perform adhesion verification when working with unfamiliar substrates.
• Store unopened kits below 27°C to maximise shelf life.

Manufacturer / Aviation Spec Codes

• Product Name: PR-1428 Class B Access Door Sealant
• Manufacturer: PPG Aerospace (PRC-DeSoto)
• Product Type: Low-adhesion two-component polysulfide sealant
• Primary Specification: MIL-S-8784 Class B
• Referenced Standards: SAE AIR 4069, AMS 3819