An apparatus and method for modifying an aspect of an exterior polymer material or polymer type material of a linear substrate with a fluid. The apparatus include a variable exposure gap within which the linear substrate is exposed to the fluid. The width of the exposure gap is varied with the speed of the linear substrate traversing the exposure gap to maintain a constant exposure time of the linear substrate with the modifying fluid.

An apparatus and method for modifying an aspect of an exterior polymer material or polymer type material of a linear substrate with a fluid. The apparatus include a variable exposure gap within which the linear substrate is exposed to the fluid. The width of the exposure gap is varied with the speed of the linear substrate traversing the exposure gap to maintain a constant exposure time of the linear substrate with the modifying fluid.

An apparatus and method for modifying an aspect of an exterior polymer material or polymer type material of a linear substrate with a fluid. The apparatus include a variable exposure gap within which the linear substrate is exposed to the fluid. The width of the exposure gap is varied with the speed of the linear substrate traversing the exposure gap to maintain a constant exposure time of the linear substrate with the modifying fluid.

An apparatus and method for modifying an aspect of an exterior polymer material or polymer type material of a linear substrate with a fluid. The apparatus include a variable exposure gap within which the linear substrate is exposed to the fluid. The width of the exposure gap is varied with the speed of the linear substrate traversing the exposure gap to maintain a constant exposure time of the linear substrate with the modifying fluid.