As the name suggests, Reverse Fill Machines are used to push coating into a substrate, thus filling the open spaces. Similar to a roll coater, a low viscosity finish is pumped or gravity fed in between the application and doctor roller. If coating is very thick the roller will run in forward to maximize coating transfer.  Once applied, the fill roller pushes the coating into the open space, levelling out the flat surface.  Available in many widths, reverse fill machines are essential for certain high build looks and high traffic environments.