A study was conducted to develop and validate a Pressurized Water Stripping (PWS) process for use on aircraft and aircraft components to allow selective removal of the topcoat. By design, the process incorporates a barrier coating to encapsulate either the epoxy (MIL-P-23377) or polyurethane (TT-P-2760) primer used on military aircraft today. Then a water-only stripping process is used to remove the MIL-C-85285 polyurethane topcoat leaving the primer and barrier coatings intact.
This system includes an inexpensive method for removing and reapplying the topcoat without disturbing the underlying primer or substrate. The barrier coating is designed to be resistant to moisture and erosion damage by the Pressurized Water Stripping process. The benefits include the preservation of the corrosion protection provided by the chromates in the primer, the encapsulation of most of the hazardous materials (alodine and primer), and the elimination of material substrate damage to the aircraft structure. In addition, there is considerable material and manpower savings in (1) surface preparation, (2) primer application, (3) subsequent depaint stages of aircraft coatings maintenance. For example, at Warner Robins Air Logistic Center (WR-ALC) it is estimated that implementation of this system will save between $5,000,000 to $8,000,000 per year.
The barrier coating is currently planned to be flight tested on cargo and fighter size aircraft starting in FY99. Flight testing will begin with non-flight critical aircraft parts with full aircraft testing commencing six months to one year after.