I wonder if the idea of soaking wood before steam bending comes from
trying to bend kiln dried wood by introducing some moisture back into
it. Certainly green wood bends easier than kiln dried. But I agree, it's
the heat, not the water that allows wood to bend. I've seen dry wood
bent with only heat. Water was used only to keep the wood from scorching.

Brian Nystrom wrote:


William R. Watt wrote:

Brian Nystrom ) writes:

William R. Watt wrote:


Old dry wood has to soak up moisture before it can be heated to bend.


Not in my experience. I've seen no difference in bending between dry
stock and the same stock that's been soaked in water for days or even
weeks. It's the heat that makes the wood bend-able, not the moisture.
Steaming is simply a way of heating the wood rapidly to the correct
temperature for bending, which - luckily for us - happens to be
around the boiling point of water.



I have no experience. Just quoting what I've read, eg. TF Jones who soaks
old wood before steam bending.


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.

On 7 Mar 2004 00:01:32 GMT, (William R.
Watt) wrote:


A 1"x1" piece of clear oak properly steamed can be tied in a knot. Not
something I've ever tried.

I'll try it sometime, and post pictures :-)

-m

Stephen Baker wrote:

Brian Nystrom says:

Soaking didn't seem to make any difference in the bend-ability of
the wood.

The old man always used to soak white oak before bending (24 hrs in the
bathtub), whether to see if it had a natural inclination to bend in a
particular direction, to help with bending, or some other reason I am not sure.
He was the builder, and I didn't question it.
He bent a lot of white oak ribs in his day.

If you're interested, try this test. Take a strip of whatever wood you
want to bend and soak it for 24 hours. Then, take a plane and see how
many strokes it takes on the surface to get down to dry wood. I scarf
thin stock for kayak coamings and the most penetration I've seen in red
oak or white ash is ~.010" on the sides and edges after soaking for 24
hours, with perhaps 1/4" penetration at the ends. I find it very
difficult to believe that this could possibly make any difference in the
bend-ability of the wood, since steaming alone will create similar
penetration in only a few minutes. As I mentioned previously, I found no
difference in bending between soaked stock and dry stock from the same
board, so I don't bother with soaking any longer. It strikes me as one
of those things that seems intuitively correct, but really doesn't help.

William R. Watt wrote:

Brian Nystrom ) writes:


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.


softwoods would have more of a tendancy to swell.

True. Before I knew any better, I tried steam bending a pine breasthook
(my first attempt at steaming anything. It sort of bent (it didn't need
much bend) and I was so excited that I immediately pegged it in place
and and planed it to shape. It looked great. The next morning, I came
down and to my dismay, it had shrunk ~1/8" in width (it was only 2"
wide) and ~ 1/16" in length (over 8 inches).

TF Jones writes that a
nice piece of 15-20 year old oak needs soaking before steam bending.

I haven't worked with anything that old, but I fail to see where age
would make any difference. Once the wood equilibrates to the humidity of
its environment, it's not going to get any drier. If it bends well at a
given moisture content, what difference would age make?

A 1"x1" piece of clear oak properly steamed can be tied in a knot. Not
something I've ever tried.

Me neither, nor have I seen anyone do it. Having worked with green,
clear oak that I've carefully cut from a log myself, I have to wonder
what the success rate of such an endeavor is? I suspect that it's only
possible with wood that has been split, rather than sawn.

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.

steveJ wrote:

I wonder if the idea of soaking wood before steam bending comes from
trying to bend kiln dried wood by introducing some moisture back into
it.

I suspect so, but it's largely futile for that, too. Aside from the fact
that it doesn't really raise the moisture content, the reason that kiln
dried wood doesn't bend well is because the lignin has be altered by the
heat of the drying process.

Certainly green wood bends easier than kiln dried.

You bet! I haven't noticed too much difference between green and air
dried wood from the same log. They both bend well, though the green wood
seems to require a bit less steaming time to achieve the same result. I
suspect that the extra moisture in the wood transfers the heat more
efficiently to the center of the workpiece (water transfers heat 25x
faster than air).

But I agree, it's
the heat, not the water that allows wood to bend. I've seen dry wood
bent with only heat. Water was used only to keep the wood from scorching.

I know people who've done a lot of dry bending, but I haven't tried it
myself. Compared to steaming, it's harder to achieve an even heat, with
scorching being a common result. I know of one guy who dry bent kiln
dried poplar! While he did manage to get it to bend, the bent parts were
terribly uneven quite charred on the outside. I think he must have been
seriously masochistic!

Brian N says:

It strikes me as one
of those things that seems intuitively correct, but really doesn't help.


I dunno. Dad had (at the tme I last saw him soaking oak) bee nbuilding,
designing and restoring boats for some 30-odd years. I know he wasn't a type
"A" personality, so can't imagine him wasting time or effort on something that
wasn't necessary to produce the perfect product.
Sadly, he died in '83, so I can't ask him to find out. I'll see if I can track
down his last apprentice and see what she has to say.
Steve

On Wed, 3 Mar 2004 23:30:09 +0100, "Marcel"
vaguely proposed a theory
.......and in reply I say!:

The problem is how do you bend wood on a yet to built boat.
I am using wood 7mm thick and 50mm wide.




Hey jerk!

You are getting some real insights here!

WTF are _you_?

************************************************** ** sorry

..........no I'm not!
remove ns from my header address to reply via email

Spike....Spike? Hello?

On Sun, 07 Mar 2004 03:29:04 GMT, steveJ vaguely
proposed a theory
.......and in reply I say!:

I wonder if the idea of soaking wood before steam bending comes from
trying to bend kiln dried wood by introducing some moisture back into
it. Certainly green wood bends easier than kiln dried. But I agree, it's
the heat, not the water that allows wood to bend. I've seen dry wood
bent with only heat. Water was used only to keep the wood from scorching.

Woah! New! I have seen "fire bending" of wood. But it was always
associated with Asian/African boats etc, where green wood was used
anyway. The idea of fire bending really dry timber, with water to
prevent scorching only, is a new "twist" G
************************************************** ** sorry

..........no I'm not!
remove ns from my header address to reply via email

Spike....Spike? Hello?

I picked up on this note. The tone was ugly. So I looked back on the
thread to see how Marcel had transgressed.
I didn't see it. So it looks kinda irrational.
Can someone explain please?

Brian W


On Sun, 07 Mar 2004 22:28:04 +0800, Old Nick
wrote:

On Wed, 3 Mar 2004 23:30:09 +0100, "Marcel"
vaguely proposed a theory
......and in reply I say!:

The problem is how do you bend wood on a yet to built boat.
I am using wood 7mm thick and 50mm wide.




Hey jerk!

You are getting some real insights here!

WTF are _you_?

************************************************* *** sorry

.........no I'm not!
remove ns from my header address to reply via email

Spike....Spike? Hello?