PPG PR1428A-1 (6-OZ-SEMKIT)

PR-1428 Class A Access Door Sealant

Overview

PR-1428 Class A is a low-adhesion, two-part polysulfide sealant engineered for aerospace access door sealing and the fabrication of form-in-place (FIP) gaskets. Cured with manganese dioxide, the material is brush-applied and cures at room temperature to produce a durable yet removable seal on common aircraft substrates. Its excellent flexibility, chemical resistance and controlled adhesion make it ideal for applications requiring repeated access during aircraft maintenance.

Key Technical Specs

• Product Type: Two-part polysulfide access door sealant
• Class: Class A
• Cure System: Manganese dioxide cured
• Colour: Part A - Black; Part B - Red; Mixed - Dark Red
• Mix Ratio (by weight): 10:100 (Part A : Part B)
• Base Viscosity: 400 Poise (40 Pa�s)
• Application Thickness: Up to 25 mils (brush applied)
• Service Temperature Range: -54°C to 121°C (-65°F to 250°F)
• Intermittent Temperature Excursions: Up to 135°C (275°F)
• Specific Gravity (Cured): 1.49
• Non-Volatile Content: 92%
• Ultimate Cure Hardness: Shore A 50
• Application Life: 30 minutes (A-1/2) or 2 hours (A-2)

Approvals & Specifications

• Tested in accordance with MIL-S-8784 Class A requirements
• Performance verified using various aerospace OEM specification test methods
• Compatible with a wide range of common aerospace substrates and primer systems

Typical Applications

• Aircraft access door sealing
• Form-in-place (FIP) gasket fabrication
• Removable sealing for inspection panels
• Maintenance access covers requiring repeated removal and replacement
• General aerospace sealing applications where low adhesion is desirable

Compatibility & Safety Notes

• Clean substrates thoroughly before application using approved solvents and lint-free cloths
• Determine adhesion characteristics on the intended substrate before production use
• Mix both components thoroughly according to the specified ratio before application
• Consult the Material Safety Data Sheet (MSDS/SDS) before handling
• For industrial aerospace use only

Packaging & Procurement

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

Why This Product is Chosen for AOG / MRO

• Creates a reliable removable seal for inspection and maintenance panels
• Excellent flexibility prevents cracking at low temperatures
• Resists aviation hydrocarbons and common aircraft operating environments
• Supports fast maintenance with brush application and room-temperature curing
• Available in cartridge and kit formats for workshop and field maintenance

Practical Suggestions for Your Team (AOG Mindset)

• Select the appropriate application life (A-1/2 or A-2) to match maintenance schedules
• Prepare sealing surfaces carefully to maximise gasket performance
• Mix complete kits thoroughly to ensure uniform curing
• Allow sufficient cure time before returning aircraft to service
• Store unopened material below 27°C to maximise shelf life and readiness

Manufacturer / Aviation Spec Codes

• Product Name: PR-1428 Class A
• Manufacturer: PPG Aerospace / PRC-DeSoto International
• Product Type: Low-adhesion polysulfide access door sealant
• Specification: MIL-S-8784 Class A
• Application: Aircraft access doors and form-in-place gaskets