re: Lets Talk "oil finishes"

Modified in oils can mean a couple things. For example, I have part of the last gallon of pure tung oil I bought. I has nothing added, but is modified by that it has been somewhat polymerized to speed its hardening. With it, I bought the heavy metal additives that cause it to polymerize more quickly.

Boiled linseed oil is just flax seed that, also, has had some of the polymerization process done in advance, to speed drying. It’s not actually boiled. Rather, the name came from the bubbling that resulted from blowing air throw it, since oxygen polymerizes the flax seed. It has heavy metals added to speed hardening too.

Oil based polyurethanes are just mixes of hardening oils, solvents and resin. The common stuff is boiled linseed oil based and the high end stuff is tung oil based.