Could you please tell me if there is any difference between polyurethane, varethane and urethane? I always thought polyurethane was more durable. Can they be used interchangeably? That is, if there is one coat of polyurethane on the wood, can the second coat be urethane? Also, how come the "Old Masters" polyurethane I used had much more substance i.e. was much thicker, than the Minwax polyurethane? The Minwax polyurethane was almost like water compared to the Old Masters product!
Urethane's urethane, no matter whom the manufacturer is. They are basically the same things. Anything with a "thane" on it is polyurethane. Now some companies have different formulas some thick, some thin, some acrylic and some solvent based. They are all compatible.