On Sat, 06 Mar 2004 14:58:04 GMT, Brian Nystrom
vaguely proposed a theory
.......and in reply I say!:

I have only done it once, to bend a piece of wood. But I understood
that if you met your sort of trouble, you soaked/steamed, then placed
the wood either in situ, but not installed, or on a former. Getting
the wood close to its final shape is enough. You then at worst need a
bit of force to finish it off.

When I've soaked wood, all it did was make is swell so it no longer fit
where it was supposed to, such as in a mortise. Either that, or if it
was trimmed to fit after steaming, it shrank as it dried and became
loose. Soaking didn't seem to make any difference in the bend-ability of
the wood.

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..........no I'm not!
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Spike....Spike? Hello?

Old Nick wrote:

On Sat, 06 Mar 2004 14:58:04 GMT, Brian Nystrom
vaguely proposed a theory
......and in reply I say!:

I have only done it once, to bend a piece of wood. But I understood
that if you met your sort of trouble, you soaked/steamed, then placed
the wood either in situ, but not installed, or on a former. Getting
the wood close to its final shape is enough. You then at worst need a
bit of force to finish it off.

Absolutely. However, If I steam bend the parts in question (kayak ribs)
without soaking, they fit without any trimming and the fit is maintained
when they dry.

When I've soaked wood, all it did was make is swell so it no longer fit
where it was supposed to, such as in a mortise. Either that, or if it
was trimmed to fit after steaming, it shrank as it dried and became
loose. Soaking didn't seem to make any difference in the bend-ability of
the wood.

I saw the photo of the 1x1 oak tied in a knot in one of the boatbuilding
books at the library, probably L Frances Herreshoff(?)

as for moisture content of wood, it does change quite a bit. We've read
here before about the importance of getting the moisture content down to
12% to prevent warping and rot. I even leave my wood cross country skis
outside for a few days before applying pine tar to the base, just to make
sure the wood is not too dry to be springy when I'm using them. I'm sure
if wood only needed to be heated to bend then for centuries boatbuilders
would have been using dry ovens instead of more complicated steam boxes
for bending. And natives would have left wood in the sun to warm up prior
to bending rather than soaking canoe ribs and planks without heat to make
them easier to bend. Anybody who wants to try a comparsion can heat wood
in an oven or microwave dry or wet and test the difference. What we don't
have in this, and many discussions, is any experimental data.

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William R. Watt wrote:

I'm sure
if wood only needed to be heated to bend then for centuries boatbuilders
would have been using dry ovens instead of more complicated steam boxes
for bending.

The advantage of steam is that it produces the proper degree of heat
repeatedly and reliably. It's by far the simplest way to do so, since no
thermostats or circulation fans are required. The heat retention of the
water vapor helps assure that the heat is evenly distributed in the box
and it transfers heat 25x faster to the wood than air does. You
certainly could use dry ovens, but on thick stock, you'd end up with a
very dry outside layer by the time the inside heated up enough to bend.

And natives would have left wood in the sun to warm up prior
to bending rather than soaking canoe ribs and planks without heat to make
them easier to bend.

No, because sunlight wouldn't produce nearly enough heat. You're making
some pretty illogical assumptions here.

Anybody who wants to try a comparsion can heat wood
in an oven or microwave dry or wet and test the difference. What we don't
have in this, and many discussions, is any experimental data.

Agreed. The closest I've come is to take pieces from the same plank,
soak some and not others, then bend them. I found no difference in
bending ability, but the tests were hardly scientific.