"Leif Thorvaldson" wrote in message
...
======LDD is hydrophilic, has a higher molar weight and in the course of
drawing out the water through the membrane of cell walls, it thins the LDD
solution. I guess that could be called a chemical reaction?

Nope, can't even be called good biology. The cells are empty of cytoplasm
in the part of the tree you save - the wood. They also contain stomata
through which liquid was exchanged. That osmosis halo only counts with
semi-permeable membranes.

Therefore, the
more wood one soaks in LDD solution, the thinner the solution gets. Ergo,
the drop in specific gravity and the need to occasionally add more LDD to
the solution. Rick didn't make any mention of adding more LDD to his 4:1
ratio of solution over time and I would be interested to hear what he does
or doesn't do in this regard. If the solution is so thinned out as to
approach the same molar weight of water in the cells, no water will be
extracted and the solution will essentially be water.

If there were a physical replacement, what did the replacement would
have
to
be regularly replenished.

=====Don't understand the question. Perhaps you could rephrase it?

Strange, because this is the only part which, by analogy to PEG, stands a
chance of being defended. Essentially the argument is that something is
"left behind" in the cellular spaces, as is true with PEG. I believe you
and others suggest it may be the glycerol. Now, having played PEG back in
the days of Moulthrop, and, unlike others, doing some research on it,
prior, I can say that:

a) Soak times quoted for LDD are absolutely inadequate for replacement.
Actually, they vary widely, even among those reporting success. Suggestive?

b) Glycerol, a liquid at normal temperatures, cannot fill cellular spaces as
PEG 1000, a solid (ok, almost solid) does _after the wood is dried_ , with
emphasis for alcohol advocates on the drying. Can't dry anything by soaking
it. Sort of like fighting for peace.

c) The volume replacement schedule you quoted is so low that, unless you're
doing tiny turnings, you can't be replacing anything significant, with PEG
(also in a recommended 50/50 solution by weight) it was not uncommon to have
to add a half pound of the solid after soaking three smallish 8-10" bowls
for the recommended three months to get back to the proper SG. Lot of space
in those empty cells. There's also a dilution, but with the short soak
times and spin while thin, that's going to be fairly small.

Answer you questions?

Hey, if you keep the surface wetted while you're working it, it can't dry
out and crack. The thinner you cut and the harder you spin, the dryer the
piece is when you take it off the lathe, and the less it will change shape,
because, as noted before, all shrinkage, like politics, is local. By
denying a large constituency of adjacent cells to pull together ... well,
red state, blue state, one pulls right, the other left and everything gets
"filibustered" so nothing's done.