WHAT IS SPAR VARNISH?
A spar varnish historically was a type of varnish used to coat the spars, or masts, of wooden sailing ships. The marine environment is viewed as the one that is the toughest on coatings, so a marine spar varnish has to be tough. Traditionally spar varnishes were made from a hard resin cooked into a vegetable oil. The most successful combination was phenolic resin cooked into chinawood, or tung oil. Linseed oil is sometimes substituted for tung oil because of its superior drying properties. These varnishes, while tough and flexible for a while, weather poorly in the sun, and become dark and brittle, requiring frequent maintenance. Over time, coating manufacturers updated these products in two significant ways. One, to keep the toughness and flexibility characteristic of a traditional spar varnish, we use polyurethane polymers in place of the tung oil. And two, we add compounds which make the varnish, and the wood beneath it, more resistant to degradation from the sun. These are called U
A spar varnish historically was a type of varnish used to coat the spars, or masts, of wooden sailing ships. The marine environment is viewed as the one that is the toughest on coatings, so a marine spar varnish has to be tough. Traditionally spar varnishes were made from a hard resin cooked into a vegetable oil. The most successful combination was phenolic resin cooked into chinawood, or tung oil. Linseed oil is sometimes substituted for tung oil because of its superior drying properties. These varnishes, while tough and flexible for a while, weather poorly in the sun, and become dark and brittle, requiring frequent maintenance. Over time, coating manufacturers updated these products in two significant ways. One, to keep the toughness and flexibility characteristic of a traditional spar varnish, we use polyurethane polymers in place of the tung oil. And two, we add compounds which make the varnish, and the wood beneath it, more resistant to degradation from the sun. These are called U
