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kudzu9
5th October 2003, 01:40 PM
I'd appreciate getting input from anyone who has had success bending bamboo. I'm mainly interested in small stuff -- up to 1/2" diameter -- for use as handles for objects like pitchers, teapots, and purses. I've done a little work with a heat gun, but always seem to get scorching, crimping on the underside, or collapse/failure. I've drilled out the septums so as to avoid pressure buildup.
I know that an old-fashioned method is to use the flame from a kerosene lamp, and I may try this. However, any tips or tricks would be appreciated. I have had a little luck bending green culms into shape and then waiting for them to dry, but I'd like something that takes less time.

Mark Meckes
5th October 2003, 05:35 PM
Hiya Kudzu,
Do you have any pics? I bet you've come up with some neat ideas! I love working with smaller pieces, branches and rhizomes included, but the crucial element, (having time) has been in scarcity of late...oh well...
This is a really interesting subject, because it reveals an extraordinary potential of bamboo... that it can be shaped into a myirad of different forms!

I'll be demonstrating this capability at an upcoming workshop, and so your question provides me with an opportunity to outline a few thoughts...so here goes...

Bamboo grows like a skyscraper, shooting fast and reaching high into the sky in a couple of months. Growing no larger, or thicker walled, it must begin it's life utilizing inherited capabilities (oh yeah, each bamboo is different), to resist breakage and collapse, while remaining flexible enough to cope with the added weight caused by heavy rains, snow, and ice, topped off with high winds.
There is good reason why bamboo doesn't produce leaves immediately upon shooting, because when leaves get wet, bamboo bends. It needs to get up there and toughen up a little, first.
It's interesting though, that a healthy bamboo contains all the fibers and structural mechanisms it needs at this early stage, which is why some of the finest bamboo paper is made from shoots after they have grown, and before they have leafed out.
Bamboo spends the remainder of it's life translocating liquid `sugary' nutrients which in turn become lignified and glue-like upon drying.
As the bamboo becomes older it becomes less flexible, (just like people), and, though stouter in character, can be more prone to breakage, (and splitting), under great pressure.
This is why basket weavers prefer younger culms (no older then middle age) for fine textured weaving.

There are many different types of bamboo bending procedures...
There's bending in the `round', bending split pieces, and bending laminated bamboo.
Then there's bending of green bamboo, bending dry bamboo, and bending partially dried bamboo (which I enjoy doing the most).
There's cold bending, heat bending, which includes dry heat, solar, gas-flame, and steam bending.
Then there's soak and bend procedures, and various combinations of the above.
The basic component of a successful bend is one in which no breakage has occurred.
The key to doing this is to increase the plasticity of the bamboo and then to utilize various jigs, devices and timing procedures to help diffuse the concentration of pressure at one point.

Success has a lot to do with getting the feel of it, and turning feel into a skill.
But it also has a great deal to do proper selection of materials, which also means...knowing the limits of what bamboo can do for you... This is why wood-benders always allow for a margin of errors and failures, which increases with the complexity of their work.

Hope these thoughts are a help.
Mark
PS Unless you want your work to be blackened, I wouldn't use kerosene... it'll be coated with soot.

bambooda
7th October 2003, 06:28 PM
Hi!

In regards to bending bamboo in tight radiuses for teapots, etc. - the ones you ususally see on Japanese teapots are actually the rhizomes of the bamboo and are solid or nearly so - they will not collapse on bending and will bend in a much tighter radius than the culm - they look like bamboo culms with the nodes, but with much closer spacing. Charley Chaplin's bamboo cane was actually made from the rhizome.

-Cal

bambooda
7th October 2003, 10:01 PM
Hi Again,

I have to qualify what I said about the rhizomes in regards to tight radius bends. I do not have a lot of experience with differant kinds of rhizomes. The ones I am familiar with are of the phyllostachys family and I usually find them in rocky soil when the rhizome runs into a rock and actually comes out of the soil and arches over the obstruction into exposure - this is how I find the ones that I use. The diameter of the rhizome depends on the variety and maturity of the bamboo clump.

- Cal

kudzu9
7th October 2003, 11:08 PM
Bambooda-
Do you have to do anything special as far as drying, etc. with the rhizomes before you can work with them?

bambooda
8th October 2003, 02:01 PM
Hello Kudzu,

I didn't track the storage time on the rhizomes, but I would advise about two to three months. If they are completely dry they are harder to bend - they need around 20% moisture content when heated for the most reliable results. If you use enough heat judiciously you may be able to process them fresh as the heat acts as sort of a speeded up drying process in itself and tempers the fibers at the same time - give it a try... By the way, these handles can be purchased ready made out of pottery supply catelogues or basket weaving catelogues.

- Cal

Tatty
15th June 2004, 10:54 PM
Does anybody know how to bend the bamboo for purse hangers? is it green bamboo and let it dry?

tom cramer
18th July 2004, 11:46 AM
Does anybody know how to bend the bamboo for purse hangers? is it green bamboo and let it dry?

Mark Meckes
18th July 2004, 02:41 PM
Hiya Tatty and Tom!
The bamboo purse handles and bent rhizome pieces are usually bent using a gas flame or oven. Often there is evidence of some scorching, or burn marks, This can be very appealing if applied with skill.
Heat bending may also have been done during a stage of the drying process of the bamboo

There are a lot of ways to bend bamboo!
... cold bending, green bending, heat bending, dry heat bending - open fire, alcohol wick-flame/gas (propane)flame, electric oven, heat gun... , steam bending, pre-soaking etc...

This subject really intrigues me because I do a lot of bending, contorting and expanding to my bamboo sculptures... very experimental.

The primary way to make to make multiple bent pieces of the same shape is to make moulds or jigs for the shapes you want to bend.
You can do it by hand too, and with lots of practice can make different shapes.

In this picture ...
http://www.bamboocraft.net/workshop/data/508/thumbs/1MVC-104F.JPG
Bending green bamboo (http://www.bamboocraft.net/workshop/showphoto.php?photo=907) - Phyllostachys aurea
This is a Phyllostachys aurea 1 3/4" dia. pole that was harvested about a month prior to bending.
In this experiment, after cutting out the strip at the top of the pole, I shaved off some of the inside of the culm, then bent the strip into a u-shape. This was done without applying heat.
Gradually working on the bend, up and down the strip helps prevent kinks, abrupt bends or breakage
After bending, the strip was inserted inside the culm and allowed to dry.
I have pulled the strip out for this pic, which also demonstrates the amount of spring-back the bent piece contains.
If I had applied a source of heat to the bend, the spring-back would be much less. This is because the extra heat would have further `plasticized' the strip, making it more supple, and upon cooling, the bamboo hardens and retains the bent shape.

Here's a picture of
http://www.bamboocraft.net/workshop/data/508/thumbs/809031009-851.JPG
`Bending bamboo rhizomes in a can' (http://www.bamboocraft.net/workshop/showphoto.php?photo=419) provided by Mary Len Chambers

Here's a pic of
http://www.bamboocraft.net/workshop/data/508/thumbs/1BendingBoo-770.JPG
`Bending bamboo culm tops' (http://www.bamboocraft.net/workshop/showphoto.php?photo=116)
As shown, a string can be used to hold the shape in place till it dries or sets. Allow for spring-back.

http://www.bamboocraft.net/workshop/data/508/thumbs/1BendingBoo-822.JPG
In this photo (http://www.bamboocraft.net/workshop/showphoto.php?photo=117) one of the branches couldn't take the pressure and collapsed.

Mark

Bamboofount
18th July 2004, 11:43 PM
How to bend P.aurea? Green? Or dried? Who can help?

Mark Meckes
7th October 2004, 11:46 PM
Hey all, how's your bamboo bending going on?
One thing I've been wanting to try out is to fill up a bamboo pole with sand, then heat up the bamboo using a propane gas torch, and try bending it.

I'd like to try it out on 1-2 inch (about 2 1/2 to 5 cm) diameter bamboo, of Phyllostachys aurea, on green and dried material.

Will put it on my Things To Do list.

Mark

ampcapo
17th November 2004, 11:42 AM
i am wanting to bend a piece of bamboo that will go in an outdoor water sculpture.
the sculpture will basically be a cross, with the cross piece curved upwards like a smile. it will be able to fit through a 4" bamboo pole (hollowed out).
can anyone guide me on how i should get started with this bent piece i need to make ?

Tatty
21st January 2005, 10:02 PM
I have some bamboo branches I would like to use for a bamboo purse hanger and it's kind of a headache for me trying to make them bend can anybody tell me what can I do to bend it..Thank you!

paulineisaachsen
30th January 2005, 07:54 PM
Hello This is my first introduction to this site. All the information I give is based on experience from our nursery and the craft we have been asked to produce over the years or friends who have specialised in the field in Japan. If there are more high tech methods that produce the same results please excuse my ignorance.
Pauline

Bamboo can be bent even straightened using heat. The application of a gas gun held about 300mm from the swiveling culm aiming somewhat below the node can effect sufficient softness to allow/remove some curvature.
For a thick handle select bamboo with close nodes. Apply the same treatment to each area near the node on the desired curve. Gently pull the ends together. Wait to cool before attempting the next section. Experiment first

Tatty
31st January 2005, 08:56 PM
Thank you pauline I'll try that, how much time should I let it stand in the heat before I start bending?

Mark Meckes
1st February 2005, 09:40 AM
Reference to 2 other threads in this forum.

http://www.bamboocraft.net/workshop/data/508/thumbs/1Mvc-141f.jpg
Strength of Bamboo: (http://www.bamboocraft.net/workshop/showphoto.php?photo=624) Branch Bending Test: Phyllostachys aurea
The branch sample (top), with the fibers showing, is the stronger piece.
The branch sample (below), was easily bent, showing
minimal fiber development.
See the article... Strength of Bamboo: Branch Bending Test (http://www.bamboocraft.net/forums/showthread.php?t=476)

------------------------------------
Here is an article in reference to Bending bamboo rhizomes into a circle (http://www.bamboocraft.net/forums/showpost.php?p=2757&postcount=2)
http://www.bamboocraft.net/workshop/data/508/thumbs/809050128-29RzmeBraclt.JPG
Rhizome Bracelet - Photo #1 of 4) (http://www.bamboocraft.net/workshop/showphoto.php?photo=1036)

Cheers,
Mark

paulineisaachsen
9th February 2005, 04:44 PM
Thank you pauline I'll try that, how much time should I let it stand in the heat before I start bending?
Sorry Tatty for the slow reponse - I got lost.
The bamboo will indicate when it is ready to bend, apply a bit of pressure from the length. Don't expect that the one node will bend the whole curve. When cooled, work on other nodes on the curve. I'm sure you have already discovered this. Damping helps if the heat looks likely to cause the fibres to separate. Of course the best handles are made from trained rhizome. For large diameter bends it has been better to split the pole then replace each bent slat (in order) onto a guide form, such as bent polyethylene pipe e.g. koetsuji fence. The Japanese fence specialist Fiona George taught me that one.