Application of Clear Urethanes, Varnishes
Common Painting Problems
t is essential to use urethanes only over a clean, smooth surface, as imperfections are easily noticed. New wood should be sanded smooth, dust removed and wiped clean with paint thinner before varnishing the dry surface. The first coat will always dry slightly gritty and must be sanded and washed. All subsequent coats should be lightly sanded and washed before recoating. The surface should be dust free as any particles will “dimple” the finish.
Urethanes are for interior use only – varnishes are to be used outside. it must be understood that all varnishes break down quite quickly because there is no pigment to protect the surface from the suns’ ultra-violet rays*. They must be recoated regularly if the varnish layer has cracked or peeled it must be stripped to bare and then re-coated with three to five coats. If the area has been left unprotected too long, any water stains may be permanent.
There are some specialty varnish or urethane products that do contain some pigment that will, to a degree, protect the surface from ultra violet light. Please discuss these products with your Operator.