Abstract: A portable system is provide for spraying viscous materials to form a truck bed liner. Tanks of coating materials that include an activator and resin are contained in a heated, portable cart which also houses a motor driving two pumps to pump the coating materials through air lines to a spray gun at a rate that can be varied by an operator. A high volume, low pressure air compressor is also mounted on the cart and in fluid communication with the air gun. The coating materials are forced through a mixing tube and out of a nozzle tip where it is atomized by the high volume air for spraying to coat the truck bed liner. A pressurized flush tank is activated immediately after spraying in order to clear the coating materials from the spray gun. A modified, dual component caulking gun containing a preselected, second colored resin and activator can be attached to the nozzle tip for decorative coloring or texturing.