Talked to the owner of Sutherland Wells this morning about polymerization and his finish. If I understood him correctly, they heat the tung oil to a certain temp and hold it there for a specified amount of time. It starts the polymerizing of the oil so it is partially polymerized. So, maybe as Sitka Deer suggested, the term polymerizing might be more appropriate. After application on your project, the polymerization becomes complete much faster than would pure, unheated tung oil. Furthermore, the finish they produce is 50-50 tung oil and solvent. The solvent keeps the oil thin enough to work easily and gasses off after application.
Regardless, I've used the Sutherland Wells product for years on gun stocks for relatively high dollar rifles and shotguns since it yields the proper look. I've also used it on top of poly, lacquer, varnish, and shellac as well as raw wood and it worked well. I apply with my hands and control the sheen by the amount of mineral spirits i add. Generally I don't want a glossy appearance, just a nice warm glow with all the pores filled.
FWIW
Phil
Last edited by TenX; 09/23/20.
