A method of masking part of a surface of a wall of a gas turbine component including at least one area having cooling holes defined therein, the method including applying a viscous curable masking compound to the part of the surface over an entirety of each of the at least one area, including blocking access to the cooling holes from the surface by applying the masking compound over the cooling holes without completely filling the cooling holes with the masking compound, and forming a respective solid masking element completely covering each of the at least one area and the cooling holes defined therein by curing the masking compound.