True tung oil comes from the nuts of a tree in China. A product that is a true tung oil will have a label that says either "pure" or "100%". If it doesn't say that on the label, IT ISN'T TRUE TUNG OIL . Forget about all the other baloney and look for one of those two words if you want to use a true tung oil. If the label contains any other chemicals, except a thinner, you are not getting a true tung oil. True tung oil takes about 3-4 months to fully cure and will emit an odor for that time.
"Tung Oil Finish" is a marketing name for products that the manufacturer thinks will result in a finish like the finish you get from a true tung oil. These "Tung Oil Finishes" may contain some true tung oil, but most do not. Their only claim to the use of the word "tung" is that it claims to give you the appearence of finish that results from true tung oil. When you buy a "tung oil finish", you are getting a "faux tung oil finish".
There are two types of "tung oil finishes". One is mixture of varnish, boiled linseed oil and mineral spirits (called an oil/varnish). The exact mixtures are proprietary but 1/3, 1/3, and 1/3 will get you real close. Some manufacturers add a dollop of drier to speed up the drying. This same mixture is frequently also called "Danish Oil" because it gives a finish that resembles the finish used on much of the "danish style" teak furniture imported in the 50's and 60's. It closely mimics a true oil finish but the addition of the varnish resins gives it more durability and protection.
Here are some oil/varnish mixtures
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Watco Danish Oil
Deft Danish Oil
Behlen Danish Oil
Maloof Finish
Behr Scandinavian Tung Oil Finish
Minwax Tung Oil Finish
Minwax Antique Oil Finish
Velvit Oil
The second "tung oil finish" is one made from varnish and mineral spirits. The approximate ratio is 1:1. This is really just a thinned varnish just like the stuff sold as "wiping varnish". When one two or three coats are applied, it also mimics the finish produced by a true oil but it is harder than the oil/varnish above because it does not have as much oil. It is slightly more protective than the oil/varnish type or tung oil finish. For all intents and purposes it is a varnish finish.
Here are some thinned varnishes
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Formby's Tung Oil Finish
Zar Wipe-on Tung Oil
Val-Oil
Hope's Tung Oil Varnish
Gillespie Tung Oil
Waterlox
General Finishes' Sealacell
General Finishes' Arm R Seal
Jasco Tung Oil
One way to tell whether the product is an oil/varnish or a wiping varnish is to read the application instuctions. Oil/varnishes are applied, then given some time to set, then wiped dry. Wiping varnish products are wiped on an left to dry (no wiping off).
For either of the above, you can mix your own using your own proportions, can it and sell it as "My Greatest Tung Oil Finish". Then announce a new product with slightly different proportion and call it "My Greatest Danish Oil Finish". We're not talking rocket science here.
Finally, I'm not saying that any of these products are not good. They are what they are and can give you a good finish when properly applied.
(*) Thanks to Bob Flexner "Understanding Wood Finishes"