Polymerized Tung Oil and Shellac

[Kevin Wilson]

I'm normally a lurker but after reading a thread on Woodweb http://www.woodweb.com/knowledge_bas..._Coatings.html several questions come to mind. If Tung Oil (the real stuff not just a small portion of the formulation) is so wonderful why don't we use it more? Has anyone ever used products from SutherlandWelles http://www.sutherlandwelles.com/ ? Twisp http://www.twispenvironmental.com/ ?

Also in a previous thread about shellac, the topic of premixed vs mix your own was discussed. It was pointed out that shellac degrades as it absorbs moisture once the can is opened. In the above thread at Woodweb, one contributor states that shellac begins to "polymerize" the moment the solvent dissolves the flakes and that even though the can is unopened, its qualities are degrading as the can sits waiting to be purchased by you and me.

Thoughts?

P.S. Now that I've come out of my shop to post I promise to be a better member of the community in the future!

[Fyrman Dave]

Hi Kevin,
I'm new here as well.
Great first post and a question that I have pondered as well. I'll look forward to the responses.
Dave

[Jim Becker]

Tung oil takes a long time to cure and is a lot more sensitive to over coating with other finishes prior to that full cure...it's very easy to ruin a finish if you don't wait long enough. While tung has a slight edge over other oils to moisture resistance after a full cure, it's not significant enough, IMHO, to supplant using garden variety BLO instead. And it's not usually an inexpensive product, either. BLO cures faster, is far less expense. BLO can even be top coated with shellac same-day if you really need to without problems. I've done that a number of times when I needed move a project along from oil to spraying my preferred water borne finishes from Target Coatings. Oil...sit for a bit...wipe...sit a little more...de-waxed shellac...dry 15-20 minutes. Scuff off nubs with 400 grit and then spray 2-3 coats of the top coat. Done in one day.