Coating removal method and guide for use therewith

Abstract

The present invention relates to a method for removing a coating from a defined area of a high pressure turbine part comprising the steps of: securing a guide to said turbine part, said guide both exposing said defined area while protecting adjacent areas; repeatedly inserting and withdrawing a brush through an opening in said guide which directs said brush to impinge said defined area and remove said coating. The invention also relates to a guide used in the aforementioned method.

What is claimed is: 
     
         1 . A method for removing a coating from a defined area of a high pressure turbine part comprising the steps of:
 securing a guide to said turbine part, said guide both exposing said defined area while protecting adjacent areas;   repeatedly inserting and withdrawing a brush through an opening in said guide which directs said brush to impinge said defined area and remove said coating.   
     
     
         2 . The method of  claim 1 , wherein said coating a corrosion-resistant coating. 
     
     
         3 . The method of  claim 2 , comprising painting said corrosion-resistant coating onto said high pressure turbine to form the coating. 
     
     
         4 . The method of  claim 1 , wherein said defined area is a dovetail slot. 
     
     
         5 . The method of  claim 4 , comprising securing said guide in said dovetail slot by inserting and wedging said guide inside the dovetail slot containing the defined coating removal area. 
     
     
         6 . The method of  claim 1 , wherein said guide comprises plastic or metal. 
     
     
         7 . The method of  claim 1 , wherein said brush comprises stainless steel bristles. 
     
     
         8 . The method of  claim 7 , wherein said bristles have a diameter between 1 and 3 mm. 
     
     
         9 . The method of  claim 8 , wherein said bristles have a diameter of 2.5 mm. 
     
     
         10 . The method of  claim 7 , wherein a defined length of said brush bristles impinge on said defined area. 
     
     
         11 . The method of  claim 10 , wherein said defined length is 0.3 to 0.5 mm. 
     
     
         12 . The method of  claim 12 , wherein said defined length is 0.38 mm. 
     
     
         13 . The method of  claim 1 , comprising stroking the brush in and out through the guide at a rate of speed between 30 and 50 inches per minute. 
     
     
         14 . The method of  claim 14 , wherein said brush is cylindrical and indexed by a controlled amount after every stroke. 
     
     
         15 . The method of  claim 15 , wherein the brush is indexed by 36 degrees after each stroke. 
     
     
         16 . The method of  claim 2 , wherein the corrosion-resistant coating is a ceramic coating. 
     
     
         17 . The method of  claim 1 , wherein said high pressure turbine part is a rotor disk. 
     
     
         18 . A guide for removing a coating from a surface of a dovetail joint of a rotor comprising: a contoured side surface adapted to interface with the teeth of a dovetail joint of a rotor; a top surface having a lip adapted to hold the guide in place against one side of the rotor and at least one hole positioned over a guide channel, wherein the guide channel includes at least one opening that exposes a surface of the dovetail joint when the guide is fitted to the rotor. 
     
     
         19 . The guide of  claim 18 , wherein the side surface of the guide includes six cavities adapted to interface with the six teeth in the dovetail joint of the rotor and six guide channels corresponding to each tooth of the rotor. 
     
     
         20 . The guide of  claim 18 , wherein the guide includes a cutout portion of the top surface.