Miniwax spar urethane question

[jeremy levine]

I read that it is "tung-modified urethane" does that mean it contains tung-oil ( the real stuff ). Is it true ?

[Jim Becker]

There may be an original ingredient that was (real) tung oil, but remember that once it's cooked into varnish, the individual properties of the oil are no longer there...it's a new substance altogether. The same holds true for BLO or soya oil, the two more popular oils used to make oil-base varnishes these days. (BLO by far is the most common) It's like baking a cake. The eggs, flour, water and other ingredients are no longer distinct once you cook it!

[jeremy levine]

Thanks, I love the color and hue the spar creates but the smell and the viscosity make me crazy. So i was trying to determine what makes it do its thing ( so to speak )

[Steve Schoene]

Viscosity is easily changed--just add thinner. Almost all oil-based varnishes need to have at least 10% additional thinner to brush out well. Manufacturers leave out thinner to lower VOC content and then lie on the label, because if they told you that thinner was needed that would be almost the same to the regulators as including it in the can.

All that said, you can do better than this Minwax product. If you are using this for exterior uses, use a real marine spar varnish that will hold up two or three times longer. If you are using it for furniture you should avoid spar varnish as being too soft for good performance. To get rich amber color try Behlen Rockhard, and for a lighter color try Pratt & Lambert 38. Waterlox also makes three tung based varnishes (but, as Jim says not tung oil now) in Satin, Gloss, and Original/Sealer. These are thinner in consistency, particularly the Original/Sealer which works well as a wipe on varnish.

[jeremy levine]

Thanks. I've used it on my exterior door ( which actually it is protected by a glass door ) looks great ( also endured temps well over 100 degrees) . I will thin it for my next project. I just smells like crap.