Method and apparatus for retaining an internal coating during article repair

A method for repairing an article including an external coating on an external surface, in which method at least a portion of the external coating is removed by exposure to a coating removal medium, the article including at least one internal passage having a passage opening through the external surface, the passage including an internal coating on a passage wall, comprising the steps of:

• isolating the internal coating from the coating removal medium about the passage opening by providing a masking assembly comprising a masking member and a substantially flexible seal, each of a material substantially inert to the coating removal medium;
• disposing the masking member about the passage opening across a gap between the masking member and the external surface;
• disposing the substantially flexible seal across the gap substantially to seal the gap;
• and then,
• exposing the external coating to the coating removal medium while retaining the internal coating on the passage wall.