[Greenbuilding] tung oil

[JOHN SALMEN]

I have always been a bit grumpy about packaged finishes. It is like coffee.
I don't want to buy Nescafe I just want beans from some identifiable origin
roasted locally with as few middle people generating profit at the expense
of quality and flavour. I got really grumpy when german low voc oil finishes
got trendy. Emulsified balsam oils with water and a bunch of stuff -
engineered and packaged nicely and shipped across the ocean. Instructions
were so complex that failure (like a Volkswagen) was unclear as to whether
it was application stupidity or just ridiculous engineering. When it comes
down to it most products are engineered to produce profit so the chemistry
engineering is really to compensate for the low cost and quality of
ingredients. 

Tung oil is basic but a very high quality product - i.e it is a finish that
has stood on its own for centuries and is not compromised by additives. It
comes from seeds from the tung tree. A deciduous tree primarily native to
china. There used to be successful plantations that were set up on the
American gulf coast but they got wiped out during some typhoon. I buy it raw
in 5 gallon quantities and have it shipped from quebec. They get it from
some wholesaler in ny who buys it from china and sells it in 50 gallon
quantities at about a 1/3 the cost and imports directly at probably 1/100 of
the cost - but at least it is a direct line to the village collecting the
seeds.

We have added thinners, colours, and waxes and occasionally have added
borates and zinc to enhance its preservative qualities for risky exterior
work. In direct sun exposure for exterior work raw oil applications (3
coats) will last 2-3 years before needing an oil wipe - beyond that the wood
will be exposed to deterioration which then subsequently requires more
frequent maintenance. In more protected exterior areas it has done well over
5 years without recoat. That is about as good as it gets for any finish.
Bona Kemi finishes are not even a contender in that regard even with the
loaded toxicity.

I have an interesting house that we have done progressive designs for
renovations. The first involved a local maple floor finished with a Bona
Kemi water based polyurethane which at the time was the only decent no voc
poly out there. I wasn't happy with the finish for a large number of reason
so the second renovation on maple and fir flooring used tung oil. A
subsequent disaster (flood) reno on another portion of the house used a
german balsam oil product. So we are looking at 15-10 and 8 years for the
various products. The Bona Kemi finish is tired and needs renewal which is a
bit of a pain, the tung oil is basically still a nice even protective finish
and some worn areas simply need a little more oil that will blend in. The
balsam oil looks quite splotchy and am unsure how additional finishing will
blend.

-----Original Message-----
From: greenbuilding-bounces at lists.bioenergylists.org
[mailto:greenbuilding-bounces at lists.bioenergylists.org] On Behalf Of Chris
Koehn
Sent: November-04-11 6:14 PM
To: greenbuilding at lists.bioenergylists.org
Subject: Re: [Greenbuilding] tung oil

Check out Land Ark products:
<http://www.landarknw.com/SearchResults.asp?Cat=18> Their finishing oils are
largely a mixture of the materials you've been asking about, and even if you
don't use their product, the info on it's use may be useful to you. 
We use their oils on timber frames with good result. We tried a finishing
oil on a walnut floor a few years ago, but had problems. I'm told Land Ark
was putting a UV inhibitor into their oils that was causing the oil not to
cure properly. I understand that problem has been solved now.

Chris Koehn
TimberGuides Design & Build
Vancouver Island
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