how do you bend wood into the boat shape?
 

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

how do you bend wood into the boat shape?
 

use a little bit of muscle or a lot of muscle or steam it first as
required

how do you bend wood into the boat shape?
 

On Wed, 3 Mar 2004 23:30:09 +0100, "Marcel"
wrote:

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

that wood's not too thick, so it should bend well with a little muscle
or steaming. I suggest using groups.google.com to search this group's
archives for 'steam bending'. A gentleman whose name escapes me has an
excellent webpage FAQ on steam bending, complete with pictures.

-m

how do you bend wood into the boat shape?
 

On Wed, 3 Mar 2004 22:40:38 UTC, "terry"
wrote:

use a little bit of muscle or a lot of muscle or steam it first as
required

You can also split the ends, say 50-100cm, from the ends to half or
third width, where the bend'n'twist are the worst.
--
steen - menzi.dk
---

how do you bend wood into the boat shape?
 

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

What boat are you building and how are you building it?


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



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

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

Spike....Spike? Hello?

how do you bend wood into the boat shape?
 

When bending 19mm marine ply for the cabin roof of 'Bluefin' I used 'G'
cramps with a large block of wood to spread the load at the gripping point.
Roof beams were 3" x 2" mahogany, 8' long with a 3" rise in centre. ie a 3"
beam cut from a 6" wide section to allow for the curve. Ply was fixed across
3 beams at its centre then cramped to shape and screwed down at 12"
intervals while still under pressure. Fixed 3 sheets that way with no
problems.
Peter
"Old Nick" wrote in message
...
On Wed, 3 Mar 2004 23:30:09 +0100, "Marcel"
vaguely proposed a theory
......and in reply I say!:

What boat are you building and how are you building it?


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



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

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

Spike....Spike? Hello?

how do you bend wood into the boat shape?
 

Max Camirand wrote:
: On Wed, 3 Mar 2004 23:30:09 +0100, "Marcel"
: wrote:

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

: that wood's not too thick, so it should bend well with a little muscle
: or steaming. I suggest using groups.google.com to search this group's
: archives for 'steam bending'. A gentleman whose name escapes me has an
: excellent webpage FAQ on steam bending, complete with pictures.

: -m

Don't know if I'm that person but here's my web page on
steambending:


Steambending FAQ with photos:

http://home.comcast.net/~saville/Steambend.htm


Here's the text:


Steambending FAQ with photos:

http://home.attbi.com/~saville/Steambend.htm

Woodworking (replica navigational instruments) and
boatbuilding webpages:

http://home.attbi.com/~saville/backstaffhome.html
http://home.attbi.com/~saville/SBOATrestore.htm


This FAQ on bending wood is provided courtesy of Gregg Germain. Any
comments would be welcome. Comments should be directed to
.

I've been in the business of steambending wood for about 15 years now.
I've built a variety of steamboxes and tried a number of boiler
systems. What you see written here is a combination of reading and
actual experience. Mostly experience.

All of my steam bending has been with Oak, Mahogany or
Butternut. I've done a little boiling work with thin birch veneer.
I've never tried any other wood as I do this work in my
boatbuilding/restoration. So I cannot comment authoritatively on
bending other woods like cedar, pine, poplar etc.

And if I haven't actually DONE it, I will not comment on it. I will
not state anything here that I have ONLY read out of a book and not
tried.

With that in mind, let's fire up the boiler....

To start with there are several rules of thumb which work quite well.

What you are doing when you are steaming wood for bending, is
softening the hemicelluloses. The celluloses are polymers that
behave the same as thermoplastic resins. [My thanks to John McKenzie
for the last two sentences].

And you need BOTH heat and steam for this. I realize that some people in
Asia "fire" bend their wood but invariably, that wood is quite wet -
typically quite green. The Norse boatbuilders used to get their planks out for
shipbuilding and sink them into a salt water bog to keep them limber until the
time came to use them.

However, we are not always so lucky as to get green
wood for our bending and you can have great success with air dried wood.
It's useful if you have the ability to soak your wood for a few days
so that the moisture content rises - those Vikings knew what they were
doing.

You need heat and you need moisture.

The primary rule is the one for steam time:

One hour of steaming per inch thickness of wood.

I have found that you can OVERSTEAM as well as understeam. If you
steam an inch of wood for an hour, try to bend it, and it cracks,
DO NOT assume that you haven't steamed it enough. There are several
factors involved which could explain the result - but we'll get to
those later. Steaming another piece longer will not help.

It is smart, however, to have a piece of stock in the steam box that
is the same thickness as the piece you wish to bend, and that is
expendable. PREFERABLY a piece taken from the stock itself. Steam that
with the target piece, and after the requisite steaming time, take the
test piece out and try to bend that to the mold. If it snaps, then
give your piece MAYBE 10 minutes more. But no more.

The wood:

Generally it is best if you can get green wood. I know that this
makes the cabinetmakers among us shudder. But the plain fact is that
green wood bends easier than dried wood. I can take a 6 foot
long, one inch thick piece of white oak; clamp one end to the bench
and hand bend the piece to the curvature I need - green wood is THAT
limber. However it won't stay bent, of course, so I steam it anyways.
In boatbuilding, rot is the main evil.

For those of us that have to worry about rot, the act of steaming
green wood removes the tendency of green wood to rot. So no worries
there - boat ribs are typically made from green, steam bent oak and will
not rot in a well cared for boat. And so this also means you can make
your Windsor chair parts by steaming green wood.

But I've done a lot of steaming of air dried oak and it works fine
too.

One thing you want to try to avoid in your selection of wood for
bending is grain runout. This will promote cracking when you bend.


So the rule of thumb in wood moisture is as follows:

1) Green is best.

2) Air dried is a good second choice.

3) Kiln dried is a distant third choice.

If all you have is kiln dried and can't get any other well then I
guess you have no choice. I have made it work.
But if you can get air dried wood that would be much preferable. Just
last week I steambent 7/8" thick Butternut boards for the transom of
my sailboat. The stock had been air dried for several years and the
bending went along just fine.


Steamboxes:

It is not necessary - and is in fact detrimental to the bending
process - to have a steambox that is absolutely airtight. You WANT
steam to be emanating from the box. If you don't get a flow through of
steam you will not be able to bend the wood - it will crack as if you
steamed it for only 5 minutes.

I know - I've created a lot of kindling in this manner.

Steamboxes can come in many shapes and sizes. You want one big enough
so that you can suspend the wood off the surface, and get a good flow
of steam around most of the wood surface. A box made of 2 x 8 pine
boards will work. One suspension method is to drill a hole through the
sides and run a hardwood dowel through. The dowel holds your wood up
and minimizes the amount of wood touching a surface. You don't want
the box to be SO big, however, such that the amount of steam your rig
generates is too small to fill up the box. You want a wet, steamy box
BILLOWING steam. So the box has to be sized to the boiler (or the
boiler sized to the box ;^) ).

I have 2 boxes:

For small stuff like 1 1/2 x 5/8 by 6 foot long oak for ribs, I use a
2 inch diameter piece of PVC. I have it resting on a 2x4 so that it
won't deform under the heat. I've also nailed sides to the 2x4 so that the
tube doesn't flatten. For a boiler I've used a whistling tea kettle
with the whistle and top taken off. A length of radiator hose connects
the kettle to a suitable reduction on the end of the PVC. For a heat
source i use one of those counter top electic burners.

Works great.

When I had to steam bend 17 foot long, 7 inch wide, 3/4 inch thick
mahogany for the new cabin trunk of my boat, I used a steambox built
with 2 x 12 inch pine. For a boiler i had a 20 gallon steel boiler.
Heat source was a propane burner I bought at Ace Hardware Store. This
burner is GREAT because it's convenient and mobile. It generates
45,000 BTU of heat. It's an aluminum
bowl on 3 legs with one burner about 8" in diameter.

Lately, I noticed a 160,000 BTU propane burner in the West Marine
Catalog for $50. I bought it. Now I'll be able to generate enough
steam to bend ribs for the Constitution.

Now when I say "one hour of steaming per one inch of wood" I mean one
hour of SERIOUS steam with NO interruptions. Therefore you have to
pick a boiler whose capacity will be sufficient for the steam time you
are looking for. I have used a 5 gallon UNUSED gasoline can for this
purpose.

NEVER put the wood in the steambox unless you have full steam and the
box is completely filled. Be ABSOLUTELY certain that you don't run out
of water BEFORE the necessary steam time. If you do, and are forced to
add more water give it up...you'll generate kindling. the new cooler
water inhibits the steam generation.

One way of maximizing the water use is to have the box tilted at an
angle so that any condensation within the box runs BACK towards the
boiler. But this requires that the fitting to introduce the steam be
located more towards the back of the box.

Another way is to set up a siphon system so that the boiler is
constantly being refilled at the rate at which water is boiling off.
A crude ascii picture of this follows:


hhhhhhh s Whe b's are the boiler
h h s s's are the steam outgo
| h | h bbbsbbbb l's are a level indicator:
| h | l b b metal tube from side
|wwwwwhw| l bwwwwwwb of boiler with clear
| h | l b b plastic vertical tube
| | llllllllb b h's is water hose from
| | b b auxilliary tank
--------- bbbbbbbb w's are water levels

Aux tank boiler

As the water in the boiler evaporates, the siphon brings more water
from the auxiliary tank. The level gauge is a simple metal tube
extending from the side of the boiler with an elbow pointing up. Over
the elbow you slip a piece of clear plastic. This way you can
observe the level of the water in the boiler. The feeder hose from the
aux tank fits inside the clear plastic level hose so that you can get
inflow and still see the water level.

One important point:

If you find you have to add water to the auxilliary tank, be
sure to add water a LITTLE BIT AT A TIME. Otherwise the flow of cool
water into the boiler will inhibit the boiling and you will get an
interruption in steam generation: not good.

It's also best to begin with a full aux tank to start with so
that you minimize the need to add cool water to the aux tank. I like
to leave a little air space in the boiler when I begin.

Many steam boxes have a door at one end to allow you to slide in
pieces when you want to - and take them out when needed. For example,
in ribbing out a boat - something you'd like to do in a day if you
can, you crank up the boiler and (when steam is up) you put in your
first piece of wood. 15 minutes later you put in the second. Fifteen
minutes later the third and so on. Then, when the first piece is
ready, you yank that out and bend it. This is all supposing that the
process to bend and install the rib takes less than 15 minutes. When
the first rib is in, the second piece of wood is ready..and so on.
This allows you to do a great deal of work while avoiding
oversteaming.

The door serves another important function. And the door doesn't have
to be solid either - on my small steam box I LOOSELY stuff in a rag. I
say loosely because you want steam to be able to come out of the end
(remember you need steam flowthrough). You don't want back pressure
building up which precludes steam entering the box. Besides - there's
nothing so cool as a steambox with steam billowing out of it - the
passersby are fascinated.

The secondary purpose is to preclude cool air from entering the
steambox underneath the suspended wood.

Bending:

Assume you have the wood cooking (it makes a nice smell) and the jig
is ready. Take pains to place everything so that the operation of
removing a piece from the box and bending it is a FAST SMOOTH
operation. Time is CRITICAL.

You have only seconds.

When the wood is ready take it QUICKLY out of the box and bend it.
GET CURVATURE ON THE WOOD!!!!!!!!!!! As fast as humanly possible. If
inserting the wood on the jig is complicated, bend it with your
hands (if possible).

On ribs for my boat - where there is a curve in 2 directions - I
take it out of the box, slip one end into a brace and bend that end
then bend the other end with my hands. Try to bend it MORE than the
amount you need in the jig. But not too much more. Then
slap the wood on the jig.

But I repeat you MUST get curvature on the wood immediately - like
within the first 5 seconds. Every second the wood cools it becomes
less flexible.

Length of wood and curvature at the ends:

There is practically NO WAY you can cut a piece to exact length and
expect to get curvature near the ends. You simply don't have the
strength and you will be thwarted by springback.

By the same token, if all you need is a 3 foot length, and
the wood is greater than, say, 1/4 inch thick, you had better cut the
piece 6 feet long and bend THAT. You can trim the wood to fit later. I
am assuming the lack of some sort of hydraulic press in your shop - i
know I don't have one. Cut the stick overlong remembering that the
shorter the stick the harder it is to bend.

And if you cut it overlong, you'll have more curvature near the final
finished end - the last 6 inches of a 1 inch thick piece of oak will
be dead straight. Depending upon the curvature you need, you may have
to resort to carving the curvature out of the end of the wood and
should size it with that in mind.

Jigs:

When you steam bend apiece of wood, and clamp it to a shape, you wait
24 hours for it to cool thoroughly. When you take it off the jig, that
wood will spring back somewhat. How much depends upon the grain and
the type of wood - it's hard to say. If your stock has a natural curvature
in the required direction to start with (I try to take advantage of this
whenever possible), you will get less springback.

So if you have to get a certain curvature to the final product, make
your jig with greater curvature.

How much?

Tis is the realm of black magick and I can't personally give you a
figure. One thing I DO know is this:

It's infinitely easier to unbend some wood that was overbent,
than it is to put MORE bend in a cool piece of wood (assuming you
don't have incredible leverage).

Once caveat: if you are bending pieces that will be glued together to
form a laminate, be sure that the jig is the exact shape you need at
glue time - I rarely get much springback from well bent, glued wood.

There are an infinite variety of jigs you can build. No matter what
type you choose, you can't go wrong if you own a clamp making factory
- you can never have too many clamps. If you are bending wood greater
than 1/2 inch thick you must see to it that the jig is built extremely
strongly: the amount of stress on it is quite high.

Quite often people will use a metal strap along the outside of the
wood as they bend. This helps to distribute the stesses along the
length of the wood and helps to prevent cracking. This is especially
true if you get grain runout at the outside edges.

Well that's all I can think of now. If I think of more I'll add it to
the FAQ.

Gregg

My woodworking projects:


Replicas of 15th-19th century nautical navigational instruments:

http://people.ne.mediaone.net/savill...staffhome.html

Restoration of my 81 year old Herresoff S-Boat sailboat:

http://people.ne.mediaone.net/saville/SBOATrestore.htm

Steambending FAQ with photos:

http://people.ne.mediaone.net/saville/Steambend.htm




--- Gregg
"Improvise, adapt, overcome."

Smithsonian Center for Astrophysics
Phone: (617) 496-1558

how do you bend wood into the boat shape?
 

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

The way they bent the spoons in "The Matrix".

If the wood won't bend you can split it into thinner pieces all or part
way, make saw cuts on the inside of the bend, or you can try moistening
and optionally heating the wood using steam, hot water, hot wet towels,
etc. A steam box is often preferred because its fast, the wood can be made
to bend more, and the wood does not get saturated with water so can be
worked when it has cooled. Green (freshly cut) wood is moist and will bend
with or without heat more easily. Old dry wood has to soak up moisture
before it can be heated to bend.


--
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how do you bend wood into the boat shape?
 

It all depends on exactly how the wood needs to be when it it done.
How tight is the bend?
There are several ways to bend wood.
1.Flex it into the shape desired and hold in place with screws, nails,
glue or lashings.
2. Steam bend the wood using a form to hold the wood until it is cool.
3. Laminate with glue two or more pieces that are flexible so that they
hold their shape went glue is set.

If you tell us exactly what you are doing we can suggest a way.


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

how do you bend wood into the boat shape?
 

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


7mm is not thick, bending that in a simple curve will not be a problem.

50mm wide will be a different problem if the curves will compound ones - ie
bend in 3 axis. Usually that width will require soaking in water or steaming
to enable bending without splitting the wood.

The internal frame or the mould will enable you to bend the wood and clamp
or staple it in position.

For some good photos and an explanation of various strip methods have a look
at www.oneoceankayaks.com

how do you bend wood into the boat shape?
 

On 4 Mar 2004 08:04:23 -0500, Gregg Germain
wrote:

Max Camirand wrote:
: On Wed, 3 Mar 2004 23:30:09 +0100, "Marcel"
: wrote:

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

: that wood's not too thick, so it should bend well with a little muscle
: or steaming. I suggest using groups.google.com to search this group's
: archives for 'steam bending'. A gentleman whose name escapes me has an
: excellent webpage FAQ on steam bending, complete with pictures.

: -m

Don't know if I'm that person but here's my web page on
steambending:


Steambending FAQ with photos:

http://home.comcast.net/~saville/Steambend.htm




Yep, that's you.

-m

how do you bend wood into the boat shape?
 

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

Gregg Germain had these posted with pics, but the link does not work
so I will direct you to one of his posts on steambending he
http://groups.google.com/groups?hl=e...edu%26rnum%3D5
You will find a lot of info here.
I can put up photos of my steamboxes and setup if you need me to let
me know.
Scotty from SmallBoats.com

how do you bend wood into the boat shape?
 

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

Sorry, just noticed that Greg is still around and still has a working
website, glitch on my end, Scotty
Glitch = user head malfunction...

how do you bend wood into the boat shape?
 

Scotty says:

Glitch = user head malfunction...

We call that a Brain Fart (tm) around here. As opposed to a "Brain Burp",
which is what you take to cure Writer's Block, or get out of the rut, or just
coz you need a break.

Steve

how do you bend wood into the boat shape?
 

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.

how do you bend wood into the boat shape?
 

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.

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how do you bend wood into the boat shape?
 

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.

how do you bend wood into the boat shape?
 

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.

Steve

how do you bend wood into the boat shape?
 

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

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

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how do you bend wood into the boat shape?
 

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.

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

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

Spike....Spike? Hello?

how do you bend wood into the boat shape?
 

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.

how do you bend wood into the boat shape?
 

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

how do you bend wood into the boat shape?
 

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.

how do you bend wood into the boat shape?
 

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.

how do you bend wood into the boat shape?
 

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.

how do you bend wood into the boat shape?
 

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!

how do you bend wood into the boat shape?
 

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

how do you bend wood into the boat shape?
 

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?

how do you bend wood into the boat shape?
 

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?

how do you bend wood into the boat shape?
 

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?

how do you bend wood into the boat shape?
 

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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how do you bend wood into the boat shape?
 

On Sun, 07 Mar 2004 14:53:54 GMT, Brian Whatcott
wrote:

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


I think Old Nick meant to point out that Marcel isn't participating in
the thread. I don't see why that's a problem... the guy asked because
he doesn't know, so he presumably doesn't have anything to contribute.

-m

how do you bend wood into the boat shape?
 

On Sun, 07 Mar 2004 10:08:40 -0500, Max Camirand
vaguely proposed a theory
.......and in reply I say!:


I think Old Nick meant to point out that Marcel isn't participating in
the thread. I don't see why that's a problem... the guy asked because
he doesn't know, so he presumably doesn't have anything to contribute.

-m

How about:

Hey guys, I am listening to the answers that people take time to
provide, at my request?

Thank you?


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

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

Spike....Spike? Hello?

how do you bend wood into the boat shape?
 

On Sun, 07 Mar 2004 14:53:54 GMT, Brian Whatcott
vaguely proposed a theory
.......and in reply I say!:

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?
Easy. I get sick of people who come here and ask questions (and the
question was minimally asked) and then can't be bothered to show an
interest in the efrfort people put into replying.
************************************************** ** sorry

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

Spike....Spike? Hello?

how do you bend wood into the boat shape?
 

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.

how do you bend wood into the boat shape?
 

Old Nick says:

Easy. I get sick of people who come here and ask questions (and the
question was minimally asked) and then can't be bothered to show an
interest in the efrfort people put into replying.

Assuming he's even reading the replies anyway. Most folks with questions like
that just assume they'll be answered by email as we'all have nothing better to
do with our time, being newsgroup junkies 'n'all.

Steve

how do you bend wood into the boat shape?
 

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?

Steam bending reducing rot(was: how do you bend wood into the boatshape?)
 

On a related note, I've always wondered if steam bending increased the
rot resistence of wood. I was thinking that when a tree grows there are
all kinds of mold and fungus spores and bacteria that must be in the
wood just naturally. But when you steam it, these little buggers would
be killed. Sterilized.
Any body ever think of this? I wonder if it would reduce or slow fungus
growth.
Also, I don't mind if people don't follow up their questions when others
give a reply. It is a little rude, but who cares if we all can learn
from the exchange?

Stephen Baker wrote:
Old Nick says:


Easy. I get sick of people who come here and ask questions (and the
question was minimally asked) and then can't be bothered to show an
interest in the efrfort people put into replying.


Assuming he's even reading the replies anyway. Most folks with questions like
that just assume they'll be answered by email as we'all have nothing better to
do with our time, being newsgroup junkies 'n'all.

Steve

how do you bend wood into the boat shape?
 

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

Well you usually would prefer to steambend oak that was freshly cut
down int eh forest because it's moisture content is high. The Vikings
(and others) used to take freshly riven oak stock and submerge them
in a bog to keep them wet until they were used. But there, they were
trying to retain moisture - not add it in.

I dont' see where soaking 20 year old oak is going to make much
difference.


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

Hav eyou ever SEEN this done? With what length of wood? How tight a
knot?

I bend white oak for boat ribs all the time and they never get that
flexible.



--- Gregg

My woodworking projects:


Replicas of 15th-19th century nautical navigational instruments:

http://home.comcast.net/~saville/backstaffhome.html

Restoration of my 82 year old Herreshoff S-Boat sailboat:

http://home.comcast.net/~saville/SBOATrestore.htm

Steambending FAQ with photos:

http://home.comcast.net/~saville/Steambend.htm



"Improvise, adapt, overcome."

Smithsonian Center for Astrophysics
Phone: (617) 496-1558

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Steam bending reducing rot
 

steveJ wrote:
: On a related note, I've always wondered if steam bending increased the
: rot resistence of wood. I was thinking that when a tree grows there are
: all kinds of mold and fungus spores and bacteria that must be in the
: wood just naturally. But when you steam it, these little buggers would
: be killed. Sterilized.
: Any body ever think of this? I wonder if it would reduce or slow fungus
: growth.

I've never heard of that directly. But there's this:

Using green wood is usually a bad idea in boatbuilding as it promotes
rot. Yet you prefer green wood when steambending.
But the steaming eliminated the tendency for the wood to rot due to
it's "greeness".

So in that sense, steaming helps to prevent rot.

--- Gregg

My woodworking projects:


Replicas of 15th-19th century nautical navigational instruments:

http://home.comcast.net/~saville/backstaffhome.html

Restoration of my 82 year old Herreshoff S-Boat sailboat:

http://home.comcast.net/~saville/SBOATrestore.htm

Steambending FAQ with photos:

http://home.comcast.net/~saville/Steambend.htm



"Improvise, adapt, overcome."

Smithsonian Center for Astrophysics
Phone: (617) 496-1558

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