I need to create an arch. I want to bend a piece of wood,
preferably something cheap into an arc. To get an idea of
the radious I need, If I used an 8 foot length of 2x4 the
depth of the arch would be about 10 in, if that makes any
sense. It is a slight bend. I was wondering if this would
work with a flimsy wood like spruce.
Could I build some kind of jig and bend it slowly, or soak
it in something? I do have the ability to clamp it in place
but not under too much stress.
Any replies appreciated.
To e-mail me, remove all of the sevens from my address.
Chris
A 10-inch bend over an 8-foot span is not really severe. More than likely any
wood: hard or soft could be bent to this radius. I don't think you have
indicated the dimensions of the piece to be bent. If in fact it were a 2x4 it
would require a lot of force to bend the wood even if it is steamed.
If however you are bending 3/4 in stock you shouldn't have a lot of trouble.
First I would figure a way to hold the wood in the bent position for an hour or
so. Ideally you should "over bend" the piece a little as it will spring back
some. This jig could be as simple as a 2x6 with a hold down on each end and a
form to bend the wood over in the center (I.e. piece of 2x12 on edge at the
center of the span?).
Second I would soak the wood in water overnight.
Then I would steam the wood for 15 min/quarter inch thickness. The easiest and
quickest method for this might be a steam system I first saw in an article
written by President Carter in Popular Mechanics. Essentially you take a length
of stove pipe as long as your work piece, attach an elbow to the end and place
the elbow into a pot of boiling water. Place the wood in the stovepipe and stop
up the open end of the pipe with a rag. Tilt the assembly so condensed water
runs back to the pot.
Remove the wood after the time period (wear gloves!! DAMHIKT) and QUICKLY put
it in the form and secure it. Let it cool for an hour or so.
Remembering from college: Quarter sawn wood works best for steam bending, White
oak is probably the best native species. Hardwoods out perform softwoods. I
don't remember any research on kiln dried vs. air-dried. The radius that you
are contemplating however should be ok for almost any species.
subject: can kiln dried wood be bent?
>From: chris [email protected]
>Date: 1/17/2004 3:22 PM Eastern Standard Time
>Message-id: <[email protected]>
>
>
>I need to create an arch. I want to bend a piece of wood,
>preferably something cheap into an arc. To get an idea of
>the radious I need, If I used an 8 foot length of 2x4 the
>depth of the arch would be about 10 in, if that makes any
>sense. It is a slight bend. I was wondering if this would
>work with a flimsy wood like spruce.
>
>Could I build some kind of jig and bend it slowly, or soak
>it in something? I do have the ability to clamp it in place
>but not under too much stress.
>
>Any replies appreciated.
>
>
>To e-mail me, remove all of the sevens from my address.
>
>Chris
>
>
>
>
>
>
Hardwood is better for bending than softwood. Use Oak. White Oak, if this
will be in an outdoors application.
Can you kerf cut the wood on the inside of the radius? Otherwise, you
should cut it into strips no thicker than 1/4" and be prepared to bend and
glue up a laminated arch.
Steam bending might work, but you would have to get something that could
contain your 8' board while you steamed the heck out of it for two hours.
You also need a bending strap on the outer radius. Steam bending is quite a
chore ( I have some nice white oak firewood from failed attempts)
"Jon Endres, PE" <[email protected]> wrote in
message news:[email protected]...
> "chris" <[email protected]> wrote in message
> news:[email protected]...
> >
> > I need to create an arch. I want to bend a piece of wood,
> > preferably something cheap into an arc. To get an idea of
> > the radious I need, If I used an 8 foot length of 2x4 the
> > depth of the arch would be about 10 in, if that makes any
> > sense. It is a slight bend. I was wondering if this would
> > work with a flimsy wood like spruce.
> >
> > Could I build some kind of jig and bend it slowly, or soak
> > it in something? I do have the ability to clamp it in place
> > but not under too much stress.
> >
> > Any replies appreciated.
>
> A 2x4 won't bend too easily, unless you can find a pre-bent one at the
Borg.
>
> The way I'd do it is to cut the 2x4 in thin strips, make a jig for the
> proper arch, have plenty of clamps available, and then glue the strips
back
> together in the jig and clamp them until the glue sets. It's a lot of
work,
> but you'll get what you want.
>
> Jon E
>
>
On 18-Jan-2004, [email protected] (Tchswoods) wrote:
> Second I would soak the wood in water overnight.
Soaking dried wood doesn't add any benefit. You want to soak green
wood to keep it from drying, but if it's dry, soaking it will do
almost nothing.
> don't remember any research on kiln dried vs. air-dried.
It is considered that air-dried bends better than kiln-dried.
Mike
On 19-Jan-2004, Andy Dingley <[email protected]> wrote:
> Somewhere I have a big '50s handbook on glulam design (it was a
> popular large-scale architectural technique in those days). I'm sure
> there's a note in there saying that two lams and one glue line is a
> bad idea, as it's prone to twisting.
Don't know why it would twist, but it does put the maximum shear
stress on the glue line.
Mike
"chris" <[email protected]> wrote in message
news:[email protected]...
>
> I need to create an arch. I want to bend a piece of wood,
> preferably something cheap into an arc. To get an idea of
> the radious I need, If I used an 8 foot length of 2x4 the
> depth of the arch would be about 10 in, if that makes any
> sense. It is a slight bend. I was wondering if this would
> work with a flimsy wood like spruce.
>
> Could I build some kind of jig and bend it slowly, or soak
> it in something? I do have the ability to clamp it in place
> but not under too much stress.
>
> Any replies appreciated.
A 2x4 won't bend too easily, unless you can find a pre-bent one at the Borg.
The way I'd do it is to cut the 2x4 in thin strips, make a jig for the
proper arch, have plenty of clamps available, and then glue the strips back
together in the jig and clamp them until the glue sets. It's a lot of work,
but you'll get what you want.
Jon E
I actually thought of that and when I went there there was a
piece of wood that had about the same arc, but not centered.
I guess over time I could find some.
On Mon, 19 Jan 2004 19:05:54 GMT, jo4hn
<[email protected]> wrote:
>Lawrence Wasserman wrote:
>> 10 inch bow in an 8 ft length? Hell, you can probably find one already
>> made at Home Depot.
>
>And Larry is the winner of today's MJG (Make Jo4hn Giggle) award. In
>case of duplicate prizes, we award ties.
>lol.
> mahalo,
> jo4hn
To e-mail me, remove all of the sevens from my address.
Chris
On Sun, 18 Jan 2004 22:22:26 GMT, "Michael Daly"
<[email protected]> wrote:
>It is considered that air-dried bends better than kiln-dried.
For hardwood there's not all that much in it. It's possible that
kiln-dried hardwood might even steam better than _some_ air-dried,
because air-dried is often a lot older and age is also a problem in
steaming.
For resinous softwoods, a hot kiln cycle is used to set the resin. If
it has been kilned like this, then you can really forget steaming it.
My steamed timber is usually ash, but also oak, walnut and I'm about
to do some lime. I try to keep my steamed timber dry and _steam_ it,
not boil it. If you saturate the ends with water, it makes it hard to
steam the center.
--
Die Gotterspammerung - Junkmail of the Gods
I tried to bend a 2x4 this weekend and do not think this
will work too well. lots of force is required for that but
the 1x4 bent surprisingly easy. I think I might just
laminate two of them together. I can bend them but now I
have to find a way to hold them in a sprung state.
Will the wood eventually assume the bent shape, at least
partially, or will I be under tension forever? I think I
will use spruce because it is cheap and I have access to
lots of it.
Also, If I glued the flat side of two 1x4s together in a
bent state and clamped them together, wouldnt it stay bent
after the glue is fully cured?
To e-mail me, remove all of the sevens from my address.
Chris
On Mon, 19 Jan 2004 20:02:42 GMT, "Michael Daly"
<[email protected]> wrote:
>Don't know why it would twist, but it does put the maximum shear
>stress on the glue line.
It's the taco problem. It's not that it wil ltwist on its own, just
that if it does start to twist even slightly, it'll flip all the way.
On Sat, 17 Jan 2004 20:22:01 GMT, chris <[email protected]>
wrote:
>I need to create an arch.
What's it for ? Does it need to be weatherproof ? Does it need to
be square timber ?
>It is a slight bend.
This is an extremely slight bend - a 10' radius You should be able to
do this in a kiln-dried 2x4, provided you can hold it in situ
afterwards.
>Could I build some kind of jig and bend it slowly, or soak
>it in something?
Steam bending green timber is the best way to go, especially for small
radius bending. However it's hard to do in thick sections, and it is
helped by using green, straight-grained hardwood, split by riving
rather than sawing.
Good timbers to use are ash (lovely stuff to bend, not very
weatherproof), oak (a bear to bend, but good once you've done it) or
willow (very well behaved and easy to bend, but you're probably going
to be using roundwood)
For this shape, I'd bandsaw it from a pre-shaped piece of oak that
grew with a curve near this shape - but that's because I have a yard
full of such stuff and it's going for firewood otherwise.
One of your problems with any bending process is managing "springback"
and for such a shallow bend in such thick timber, then that's a
"spring" range that's almost as big as the curve. If this is rough
work, then I'd try just bending the timber by hand and holding the
ends in place.
If I really needed an accurate free-supporting arch like this,
especially if I wanted a load of them, then I'd rip my stock to 1/2"
strips and make a glulam structure, probably from Douglas Fir.
--
Do whales have krillfiles ?
On Mon, 19 Jan 2004 05:03:47 GMT, chris <[email protected]>
wrote:
>lots of force is required for that but
>the 1x4 bent surprisingly easy.
I think it's a square law on the thickness.
>Also, If I glued the flat side of two 1x4s together in a
>bent state and clamped them together, wouldnt it stay bent
>after the glue is fully cured?
If you need this thing to be self-supporting and not needs the ends
clamping, then I think glulam is a good way to do it. But I'd go for
1/2" strips.
Somewhere I have a big '50s handbook on glulam design (it was a
popular large-scale architectural technique in those days). I'm sure
there's a note in there saying that two lams and one glue line is a
bad idea, as it's prone to twisting.
--
Die Gotterspammerung - Junkmail of the Gods
Not sure exactly how this arch is being used(covered with drywall,left
expsoed etc.) but you might be able to use a product called
benderboard. Its a form of 'plywod' specifically made for bending.
Rip a couple strips of that and bend and glue to a prebuilt form. You
can also provide a better exposed surface(across the width) using 1/4
in ply with good surface. If a couple of layers are glued up it will
be quite strong and hold shape v well.
BTW - benderboard(may go by other names depending on where you are)
only bends in one direction and so is made in 2 forms;one to bend
lengthwise and another to bend widthwise.
On Sat, 17 Jan 2004 21:28:23 GMT, "Jon Endres, PE"
<[email protected]> wrote:
>"chris" <[email protected]> wrote in message
>news:[email protected]...
>>
>> I need to create an arch. I want to bend a piece of wood,
>> preferably something cheap into an arc. To get an idea of
>> the radious I need, If I used an 8 foot length of 2x4 the
>> depth of the arch would be about 10 in, if that makes any
>> sense. It is a slight bend. I was wondering if this would
>> work with a flimsy wood like spruce.
>>
>> Could I build some kind of jig and bend it slowly, or soak
>> it in something? I do have the ability to clamp it in place
>> but not under too much stress.
>>
>> Any replies appreciated.
>
>A 2x4 won't bend too easily, unless you can find a pre-bent one at the Borg.
>
>The way I'd do it is to cut the 2x4 in thin strips, make a jig for the
>proper arch, have plenty of clamps available, and then glue the strips back
>together in the jig and clamp them until the glue sets. It's a lot of work,
>but you'll get what you want.
>
>Jon E
>
Make a jig out of a sheet of MDF or plywood, with dowels or other
vertical support member to clamp the lamination to in the curve you
want
John
On Mon, 19 Jan 2004 05:03:47 GMT, chris <[email protected]>
wrote:
>
>I tried to bend a 2x4 this weekend and do not think this
>will work too well. lots of force is required for that but
>the 1x4 bent surprisingly easy. I think I might just
>laminate two of them together. I can bend them but now I
>have to find a way to hold them in a sprung state.
>
>Will the wood eventually assume the bent shape, at least
>partially, or will I be under tension forever? I think I
>will use spruce because it is cheap and I have access to
>lots of it.
>
>Also, If I glued the flat side of two 1x4s together in a
>bent state and clamped them together, wouldnt it stay bent
>after the glue is fully cured?
>
>
>
>
>
>
>To e-mail me, remove all of the sevens from my address.
>
>Chris
In article <[email protected]>,
chris <[email protected]> wrote:
>
>I need to create an arch. I want to bend a piece of wood,
>preferably something cheap into an arc. To get an idea of
>the radious I need, If I used an 8 foot length of 2x4 the
>depth of the arch would be about 10 in, if that makes any
>sense. It is a slight bend. I was wondering if this would
>work with a flimsy wood like spruce.
>
>Could I build some kind of jig and bend it slowly, or soak
>it in something? I do have the ability to clamp it in place
>but not under too much stress.
>
>Any replies appreciated.
>
>
>To e-mail me, remove all of the sevens from my address.
>
>Chris
10 inch bow in an 8 ft length? Hell, you can probably find one already
made at Home Depot.
--
Larry Wasserman Baltimore, Maryland
[email protected]