|Forum topic by daveingva||posted 05-26-2011 03:24 PM||5600 views||0 times favorited||8 replies|
05-26-2011 03:24 PM
I have a query about Lee Valley Tools polymerized tung oil. I’ve used it as my preferred finish – usually as a medium luster (1 part Sealer to 2 parts High Luster) – for many years.
This January I was unusually for me using the tung oil straight as a High Luster finish on a pear wood coffee table I was making for a friend. I was on my 4th and final coat, after having given 24 hours between coats. When I came out to my garage to check on my final coat I was shocked to see the finish had dried in a “clouded” fashion, with streaks of very matte type finish interspersed with the rest which was a brilliant gloss. I put that down to a rapid temperature drop and my workshop garage being unheated. It meant stripping the table and redoing the finish. One thing I did notice was the high luster tung oil I was using was the dregs of a can that had been opened for some time (perhaps even as long as 2 years) and which had congealed a skin across the top which I had poked through and worked with the uncured oil underneath.
Anyway, I had thought the January episode was a one off bit of bad luck related mostly to cold weather that dropped my workshop temp from 12C to around 4C and perhaps was also somehow related to using “old” tung oil which had skinned over.
Fast forward to today, where I have been applying some touch up maintenance coats of medium luster polymerized tung oil to a coffee table I’ve built and which sits in our living room. The tung has been drawn from a jar of a medium luster mix which I made back in January or so. I cannot remember if I was mixing sealer and high luster from cans that had been open a long time but as I live in Switzerland I have tended to buy things like tung on one off shipments and I cannot remember buying tung from LVT in the last 4 years. So probably whatever I am mixing up has been in the can for a good few years, although at least initially the stuff has never been exposed to air. So anyway, the medium luster mix would have been made in January but then had been sitting in a glass jar at a half full level and I started using it for my living room coffee table about 4 days ago. Once more I have been applying the tung with a cheesecloth and 24 hours between coats. The first 3 coats went on well, and last night I put on the 4th coat. I was surprised and very depressed this morning to find the 4th coat had again cured in a cloudy, matte fashion over approximately half the table surface.
This time the table was in our heated home, so a temperature drop is not the culprit. I have noted that in the jar I have been using there has been some congealing of some of the tung oil around the edges so that seems to be the only common factor between the two episodes. Is it possible that my entire stock of tung oil is simply out of date? Has anyone else seen this kind of thing? Does anyone have an explanation for what has happened? And is there any way I can salvage my table without stripping it all off and refinishing?
The followin photos show the sad story.
Thanks for your comments and advice.