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.

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!

On Sun, 07 Mar 2004 13:05:27 GMT, Brian Nystrom
wrote:


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!

Luthiers normally dry bend over a heated pipe. A man I knew who
hotbent lute staves (about 1 mm thick) would put them outside
overnight if they got totally dessicated.

He never soaked anything, even though wood that thin might have wet
through. One reason was that he used curly maple. If he soaked that
after thinning it it would get all ripply. Violins often have curly
maple, so the same would apply.

On a separate but related matter, Flemish harpsichord makers of the
16th and 17th centuries hot-bent the curved bentside of their
instruments. These were made of limewood or European poplar (populus
spp) not tulip poplar as we have in the US.

This did char as they bent it. They scraped the charcoal off so they
could paint afterwards, which accounts for the side being thinner at
the point of sharpest curvature. As far as anyone knows, this practice
continued from circa 1500 to ca 1700. I don't believe they wasted any
time doing it.




Rodney Myrvaagnes J36 Gjo/a

Smoking in a bar is like peeing in a punchbowl.

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?

Well Nick, I must admit that where I saw this was not on a boat.
Musical instrument makers have been doing this for centuries to bend the
sides of guitars and such. Though the wood was thin, I've seen a guitar
maker bend honduran mahogany using a two inch iron pipe that was set up
on a stand with a propane torch burning in the middle of the pipe.
water was sprayed on the surface of the wood to prevent burning. Worked
very well. I wonder if this concept/tool cold be used for larger pieces
for bending ribs on small boats. I see no reason why it wouldn't work
when making small ribs like for a kayak or something.

Old Nick wrote:
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?

steveJ wrote:

Well Nick, I must admit that where I saw this was not on a boat.
Musical instrument makers have been doing this for centuries to bend the
sides of guitars and such. Though the wood was thin, I've seen a guitar
maker bend honduran mahogany using a two inch iron pipe that was set up
on a stand with a propane torch burning in the middle of the pipe.
water was sprayed on the surface of the wood to prevent burning. Worked
very well. I wonder if this concept/tool cold be used for larger pieces
for bending ribs on small boats. I see no reason why it wouldn't work
when making small ribs like for a kayak or something.

I suspect that it would be difficult to get even heating of a 1/4" thick
kayak rib, but it might be worth a try. However, steam bending is so
easy that I'm not sure if the experiment would be worth the effort.

On Thu, 11 Mar 2004 15:34:31 GMT, Brian Nystrom
wrote:

steveJ wrote:

Well Nick, I must admit that where I saw this was not on a boat.
Musical instrument makers have been doing this for centuries to bend the
sides of guitars and such. Though the wood was thin, I've seen a guitar
maker bend honduran mahogany using a two inch iron pipe that was set up
on a stand with a propane torch burning in the middle of the pipe.
water was sprayed on the surface of the wood to prevent burning. Worked
very well. I wonder if this concept/tool cold be used for larger pieces
for bending ribs on small boats. I see no reason why it wouldn't work
when making small ribs like for a kayak or something.

I suspect that it would be difficult to get even heating of a 1/4" thick
kayak rib, but it might be worth a try. However, steam bending is so
easy that I'm not sure if the experiment would be worth the effort.

How even does it have to be? As I posted earlier, the curved sides of
Flemish harpsichords were bent over a hot iron, probably the top of
the shop stove, for about 2 centuries. The bent side started over 1/2
in thick. It is a little thinner at the area of greatest curvature
because they had to scrape the charcoal off before they could paint
it.


Rodney Myrvaagnes J36 Gjo/a

Smoking in a bar is like peeing in a punchbowl.

Rodney Myrvaagnes wrote:

I suspect that it would be difficult to get even heating of a 1/4" thick
kayak rib, but it might be worth a try. However, steam bending is so
easy that I'm not sure if the experiment would be worth the effort.


How even does it have to be? As I posted earlier, the curved sides of
Flemish harpsichords were bent over a hot iron, probably the top of
the shop stove, for about 2 centuries. The bent side started over 1/2
in thick. It is a little thinner at the area of greatest curvature
because they had to scrape the charcoal off before they could paint
it.

Well, I wouldn't want to be scraping any charocal off a rib that's only
1/4" thick to start with. Burning the outside in order to get the inside
hot enough to bend seems pretty ridiculous when you can steam the part
and have it bend with no damage. Perhaps the harpsicord makers couldn't
do this for some reason or perhaps there is something about the wood
they used that precluded it?

On Fri, 12 Mar 2004 18:49:00 GMT, Brian Nystrom
wrote:

Rodney Myrvaagnes wrote:

I suspect that it would be difficult to get even heating of a 1/4" thick
kayak rib, but it might be worth a try. However, steam bending is so
easy that I'm not sure if the experiment would be worth the effort.


How even does it have to be? As I posted earlier, the curved sides of
Flemish harpsichords were bent over a hot iron, probably the top of
the shop stove, for about 2 centuries. The bent side started over 1/2
in thick. It is a little thinner at the area of greatest curvature
because they had to scrape the charcoal off before they could paint
it.

Well, I wouldn't want to be scraping any charocal off a rib that's only
1/4" thick to start with. Burning the outside in order to get the inside
hot enough to bend seems pretty ridiculous when you can steam the part
and have it bend with no damage. Perhaps the harpsicord makers couldn't
do this for some reason or perhaps there is something about the wood
they used that precluded it?

First, they started with it thick enough to end up as desired. Second,
the iron was on the inside of the curve (which is the outside of the
harpsichord. Third, what they did was probably the fastest way to do
it. They were not into spending a lot of time savoring the process.


Rodney Myrvaagnes J36 Gjo/a

Smoking in a bar is like peeing in a punchbowl.