John wrote:

One thing that springs to mind, is like most things , failure occurs at
the weakest point.

So as the wood dehydrates, we get shrinkage.

If we then have a weak point, and the forces involved in the shrinkage
are strong enough, we will get a crack, starting at the weak point.

Now if we re-hydrate the wood, the wood will likely return to the shape
it had before, dehydration, hence closing the gap. The adhesive, in the
solution causing the surfaces either side of the crack to bond.

In addition to this the adhesive provides reinforcement for the wood
around the crack, so that as the wood again dehydrates, it is less
likely to crack again, in this location, though it could be that the
forces are strong enough to find a new weakness.

I never tried this trick, but it sounds like the glue/water mixture
soaks into the wood, swelling the crack closed, When the wood again
dehydrates, just the water evaporates leaving the glue to keep the crack
"swelled" shut. I reckon if just the holding power of the glue forced
the crack to stay closed, you would stand a better than even chance the
crack would re-appear there or somewhere else. The glue that remains in
the wood keeps it in a swelled/stable state forever.

In other words, I'm thinking the bonding part is minor compared to the
left over swelling? Just my guess though, not sure.
--
Jack
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