Questions about water displacement in wood cells while drying, or oil
soaking snipped...

My understanding is that initial drying is the loss of cell body (inside the
cell) water. this would be where almost all of the shrinkage occurs. Because
the cell bodies are basically boxes of stuff, oil should replace it pretty
well, filling in any voids.

        as a zoologist, Animal cell walls don't have a ton of water in them.
Plant cell walls re a lot thicker and more structural, and may have water,
but a plant biologist could answer that better than I. As far as water
displacement: I don't think an oil would replace any bound (molecules held
in place by chemical or physical properties of the media they are in) water.
water is a pretty small molecule (compared to oils), so a physical
displacement is unlikely. When water is held chemically, its usually because
water is polar (like a magnet), and I'm pretty sure oils aren't, so that
shouldn't displace it either.
        the only water that I think the oil would displace would be "free"
water - water that isn't held in by any particular mechanism other than the
fact that there's stuff around it preventing it from evaporating away.
        My (limited) understanding of how the oil works to help a cracked
plane is as follows:
        When the plane was made, it was (presumably) made of fairly well
seasoned wood, and may have had a surface finish put on. The blade is
fitted, and everything fits nicely. Zoom past N years. The plane has been
used without a lot of geographic moving around. Its well acclimated to where
it is, and any minor shrinkage or expansion has been adjusted for over the
years as the plane has been used.
        Enter the Galoot. The plane is scooped up and probably moved pretty
far away. Across the ocean, US, or whatever. In any case, into an area that
ahs a significantly different hot/cold/humidity environment.
        The surface of the wood adjusts quickly, the center more slowly, and
the plane checks (cracks).It checks because the inside and outside of the
plane have different moisture contents, and so, are different sizes. Enter
the oil. The plane is soaked in oil, and the wood becomes saturated (or
nearly so) with oil. The outside and inside of the plane may have different
moisture content, but he oil content is the same (and probably will remain
the same for more or less ever). As the oil soaks into the wood, there is a
certain amount of expansion, and the cracks (being the path of least
resistance) close up.
        If a polymerizing oil is used, over time, the plane will become a
block of polymerized oil, and will be really stable. If a non-polymerizing
oil is used, it *should* ooze out (but who knows what will really happen?
Stay tuned for more)...
        This technique is more or less what is used by biologists to prepare
tissue microscopy. You replace all of the water with unpolymerized plastic,
polymerize the plastic, and now you've got something that you can slice
really thin (like lightwave thin)...
                        --JD