Abstract: A method and apparatus for applying a coating of thermoplastic resin to the surface of low grade plywood panels so as to form smooth surface suitable for use in concrete forms or the like is described. Polyamides or like resins are applied to the surface of a panel and the panel passed beneath an extruder or doctor blade provided with upwardly inclined surface that accumulates a puddle of resin on the upstream side of the extruder blade. The panel leaves the extruder with a coating of resin which fills knot holes and other surface defects. The coated panel is passed through an oven heating only the top side of the panel thereby allowing a bottom portion of the resin layer which is nearest the wood to solidify while a top portion remains liquid. The panel may then either be covered with a layer of paper and compressed between nip rollers or passed beneath a smoothing device, such as a reverse wiping roll or a doctor blade, to smooth the upper portion of the resin layer.