The Soap Solution - Leif O. Thorvaldson

 Having a reawakening to the pleasures of woodturning after a gap of four
years, I plunged into it with enthusiasm. Joining the South Puget Sound
Chapter AAW, buying books and videos and eagerly reading all the posts on
rec.crafts.woodturning along with visiting every site, both personal and
commercial. I became increasingly discomfited by what I read and learned.
Experienced turners and professional turners were constantly carrying on
about multitudinous ways of "drying" wood so as to avoid cracking. One way
in particular had my hasty heart dismayed when it was described that one
should rough turn the wood, slather it up with various lotions and potions
and let it sit for six months to six years. One was to build an enormous
pile of these objects by constantly adding to the drying rack and, at the
end of the six months (or six years), check to see if the roughed out blank
had cracked or warped so badly as to be unusable. If not, one could then
turn it to completion, finish it and hope that it wouldn't crack thereafter.
Faster methods were suggested: boiling, micro waving, burying in manure
piles, compost heaps, sawdust piles, storing in sealed plastic bags,
unsealed plastic bags, dry paper bags, wet paper bags, immersing or spraying
with WD-40, ad nausea. None of these did what I wanted to do, i.e., pickup
a piece of green wood, turn it, sand it and finish it within a day or two
without unsightly cracks occurring.

One fateful day, browsing on my computer while waiting for the first six
months to elapse, I encountered a very lovely website by Ron Kent
(http://www.ronkent.com/RKgallery.html). He had some beautiful
Norfolk Pine
turnings -- very thin -- and used some unique finishing techniques. All
very nice, but what struck me was a technique he had developed for
stabilizing and conditioning wood. He had tried the expensive route, but
was looking for something under $50 per gallon. To make his story short, he
found that Costco's house brand (Kirkland) liquid dishwashing detergent
mixed with an equal amount of water provided hitherto unavailable qualities
in both conditioning and stabilizing of wood for almost immediate turning
and finishing

I went to Costco and purchased four half gallon containers of the magic
elixir along with a sturdy plastic storage bin of sufficient size to hold
the mixture and some bowl blanks. Upon arrival at home, I emptied the
detergent into the container and added an equal amount of water. From then
on, I would take primarily green wood and rough turn in one day, soak
overnight, and finish the next day. Sometimes I didn't finish it on the
second day and left it mounted on the lathe overnight and sometimes for a
several days. Surprise! They didn't crack! I have since taken green wood,
rough turned it, soaked it about four hours and then finish turned it and
finished it in one day. In the six to eight months I have been using this
technique, I haven't had one bowl crack. A few had a bit of movement, but
it was very slight. I have used the following woods: black walnut, vine
maple, maple, oak (kiln dried), yew, honey locust, fruiting cherry, birch,
plum, apple. I have not tried madrona as I refuse to cut down the only one
I have growing on my property.

Needless to say, I was ecstatic and proceeded to share my "discovery" with
any and all turners I knew (two) and also spread the word on
rec.crafts.woodturning (a regular not-so-little Johnny Appleseed I was!). A
few turners were lured into trying it. Unfortunately, some people can't
follow directions and tried variations on the simple recipe which resulted
in cracking. A few did it correctly and were rewarded with success.

There has been some speculation as to the mechanism behind the process, but
no real scientific investigation has been done. Lyn Mangiameli, John
Nicklin and I have come up with the following theory which John set to
words

”The soap solution sets up an osmotic gradient. Pure water in the wood is in
more abundance than water in the soap solution, so it (the water) tries to
migrate to balance the osmotic pressure. This would cause the specific
gravity of the soap solution to decrease (although possibly not noticeably.)
On the other hand, the concentration of soapy stuff is higher outside the
wood than in, so it tries to migrate into the wood. If it is successful in
migrating into the cells, the soapy solids will get trapped as the wood
dries, preventing the cells from collapsing as they do when wood dries
naturally (or unnaturally for that matter.)

As you point out, the soap solution is slicker than a Teflon banana peel.
This may help the migration of soapy solids into the cells."

An attempt was made by Lyn to conduct a survey to gather details for a study
on the detergent/soap technique. Unfortunately, he received only 11
responses from turners, so feels that no meaningful statement can be made as
to the efficacy of the process.

The only slight drawback to the detergent solution is that the wood should
be drained for a few minutes or longer and wiped with a towel while mounting
it to the headstock. A plastic sheet should be placed over the ways and eye
protection should be worn. Try it! Your hands will be smoother, cleaner
and less subject to cracking as well as your turnings.

Leif O. Thorvaldson
Eatonville, WA
360-832-4352