Abstract: An improved method for determining that coating has been removed from an article surface is provided for use in a method of removing a selected coating from an article surface having a composition different from the coating by impacting the coating with abrasive particles. The improved method includes selecting from the light spectrum a color which provides a color contrast between light emitted from the coating and light reflected from the article surface during coating removal in an impact intensity range using the abrasive particles. Provided is the selected color light environment in which the coated article surface is placed and then impacted with abrasive particles in the impact intensity range to create the color contrast and to remove coating from the article surface, the impact would be conducted until the color contrast disappears.

Abstract: A method and apparatus for masking from treatment selected surfaces of a turbine blade. The blade is positioned in an apparatus which includes a holder enclosing the airfoil section of the blade and a distinct spaced apart mask member elastically secured to the holder and having a deformable surface covering a surface of the blade spaced from the airfoil.