varnish vs polyurethane

[Jim]

What is the primary difference between polyurethane and varnish in use on refinishing the sole? Hardness? Quick drying? other?

 

[patrick]

I think that the main thing

is that polyurethane chemically sets and varnish never does. Varnish is a solvent based coating and when it (the solvent) evaporates, the coating gets hard but never reacts chemically. Thus the varnish is easier to remove and true polyurethane chemically bonds to the substrate. You will have a much harder time removing polyurethane.

 

[Steve O.]

both are varnish

One is polyurethane varnish and the other I assume you are talking about oil base or "Spar" vranish. Poly is harder, a synthetic which chemically sets and hardens, while oil base is organic, usually linseed oil, and as Patrick explained, dries when the solvent spirits evaporate leaving the oil base protectant.