A method of applying an electric conductive layer to selected portions of a foam mount, the method comprising: providing a foam mount, the foam mount in a shape having an enclosed frame surrounding an open area, the frame in cross section having a peripheral surface; an inner surface (41, 42) opposite to the peripheral surface, the inner surface (41, 42) defining the open area; a first side extending from the peripheral surface to first portion of the inner surface, and an opposite second side extending from the peripheral surface to second portion of the inner surface, wherein the inner surface (41, 42) of the foam mount includes open end of a groove and the open end of the groove faces the open area of the foam mount, and the first portion is on one side of the open end of the groove and the second portion is on the other side of the open end of the groove; applying a first electric conductive coating over the inner surface of the groove; inserting the peripheral edge of a substrate in the groove to completely cover the open area of the foam mount to separate the foam mount into a first section and a second section, wherein the first section comprises the first side and the first portion, and the second section comprises the second side, and the second portion; applying a second electric conductive coating over the first section, wherein the coating on the first portion and the coating on the inner surface of the groove contact one another, and applying a non-electric conductive coating over the second section. providing a foam mount, the foam mount in a shape having an enclosed frame surrounding an open area, the frame in cross section having a peripheral surface; an inner surface (41, 42) opposite to the peripheral surface, the inner surface (41, 42) defining the open area; a first side extending from the peripheral surface to first portion of the inner surface, and an opposite second side extending from the peripheral surface to second portion of the inner surface, wherein the inner surface (41, 42) of the foam mount includes open end of a groove and the open end of the groove faces the open area of the foam mount, and the first portion is on one side of the open end of the groove and the second portion is on the other side of the open end of the groove; applying a first electric conductive coating over the inner surface of the groove; inserting the peripheral edge of a substrate in the groove to completely cover the open area of the foam mount to separate the foam mount into a first section and a second section, wherein the first section comprises the first side and the first portion, and the second section comprises the second side, and the second portion; applying a second electric conductive coating over the first section, wherein the coating on the first portion and the coating on the inner surface of the groove contact one another, and applying a non-electric conductive coating over the second section. applying a first electric conductive coating over the inner surface of the groove; inserting the peripheral edge of a substrate in the groove to completely cover the open area of the foam mount to separate the foam mount into a first section and a second section, wherein the first section comprises the first side and the first portion, and the second section comprises the second side, and the second portion; applying a second electric conductive coating over the first section, wherein the coating on the first portion and the coating on the inner surface of the groove contact one another, and applying a non-electric conductive coating over the second section.