Fred Hargis· Registered
Oil based finishes have just about an indefinite life, until the can is opened. That allows the start of the curing process and it won't be long until it's, well, cured. That's waht you are seeing. You can do things like Dave suggested (and a few others) to slow it down, but it's best not to expect it to last too long once opened. Keeping it in a refrigerator also helps. For what seems to work best is to either 1: cover the finish with a piece of wax paper cut to fit inside the can, or 2: fill the finish can with something (marbles) until it's full enough to push almost all the air out.