Sherwin Incorporated are one of two Pratt and Whitney approved manufacturers of the “Penetrant System Monitoring Panel” which provides a quick means of determining the continued serviceability of liquid penetrant inspection systems: fluorescent or visible; water-washable; post-emulsifiable, or pre-wash.
Sherwin Incorporated manufactures each PSM-5 panel to P&WA specifications. A stainless steel panel, 0.090″ thick and measuring 4 x 6 inches. A chrome or grit plated strip runs the length of one side of the panel. Five cracked starbursts are evenly spaced in the chrome or grit plating in order of magnitude; the largest is readily visible with low sensitivity penetrants, while the smallest is difficult to observe even with high sensitivity materials.