Wood finishing materials

right|thumb|upright=1.4|Some of the many different colors of shellac thumb|right|Shellac in alcohol

yellowish oil obtained from the dried, ripened seeds of the flax plant

thumb|right|Varnish on wood stairs thumb|Varnished oak floor

class=skin-invert-image|thumb|right|Polyurethane synthesis: the urethane groups −NH−(C=O)−O− link the molecular units, resulting in a polymer consisting of an alternating chain of two monomers. thumb|A kitchen sponge made of polyurethane foam

polymer

oil that hardens to a tough, solid film after a period of exposure to air

vegetable oil

oil extracted from English walnuts

preparatory coating put on materials before painting