PPG Chrome-free Corrosion-inhibiting Aerospace Sealant

Applications for a chrome-free corrosion-inhibiting aerospace sealant by PPG continue to grow as aircraft manufacturers and maintenance, repair and overhaul shops report the product surpasses their process and performance expectations. Available in all three classes, PRC PR-2870 sealant is becoming the new standard by which other corrosion-inhibiting sealants are measured.

According to Bill Keller, PPG global market segment manager for aerospace sealants, customers have commented that PR-2870 sealant hits key targets they seek in their next-generation fuselage and pressure sealants.

“It is the right stuff at the right time,” Keller said. “When we asked customers to name the properties they wanted in their sealants, first was rapid cure, and light weight was a close second. All PR-2870 sealant classes cure faster than our previous-generation corrosion-inhibiting sealant, while Classes A and B weigh as much as 30 percent less by volume.”

PR-2870 sealant for roller application (Class C) is now available with 48-hour application and assembly time for large, complex aircraft structures. Like the other Class C grades, it cures 70 percent faster than traditional interfay sealants at ambient conditions, reducing cycle time to offer aircraft manufacturers and maintainers the potential for cost savings.

“PR-2870 Class C sealant provides the long work life and assembly time required for structural assembly, but then it achieves cure in less than half the time of older-technology sealants,” Keller said. “This will radically enhance production line efficiency.”

The proprietary PPG chrome-free corrosion-inhibiting sealant will soon be available for spray application that will enable coverage of wide areas for self-leveling fairing over countersunk fasteners and as a flexible primer under paint in areas such as wheel wheels to protect against stone chip impact.

Rapid-curing sealants enable customers to seal parts faster and move them through the process more quickly. Lighter weight sealants also improve operating efficiencies of aircraft, Keller said.

PPG has qualified PR-2870 sealant in viscosities for application by brush (Class A), extrusion (Class B) and roller (Class C), with half-hour and two-hour work times for Classes A and B and 12-hour and 24-hour options as well as a new 48-hour option for Class C. PR-2870 sealant also is qualified to U.S. Military Specification MIL-PRF-81733.  It is supplied in a two-part SEMKIT package or premixed and frozen cartridge.

A replacement option for PRO-SEAL 870 sealant, PR-2870 sealant uses PPG-patented technologies to inhibit corrosion on metal in aerodynamic smoothing, structural surface sealing, fay sealing and pressure fuselage sealing aircraft applications.

“For more than 50 years, Pro-Seal 870 sealant was the standard for corrosion-inhibiting aerospace sealants,” Keller said. “PR-2870 sealant maintains superior corrosion protection in a chrome-free formulation that complies with European Union REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) regulation.”