Preventing bamboo from cracking (P. n. 'Bory')

[Pondman]

Hi everyone- I am a new member but I have been growing a stand of Bory (tiger) bamboo for about 10 years. I have been recently harvesting and working with it to make trellises, hiking sticks, and flutes. I have just recently started heat treating (torching), drilling out the inner nodes, and using sealers and finishes . I would like to know which technique would result in fewer cracks- heat treating alone or heat treating and drilling out the cores?
Andy

[Mark Meckes]

Hi Andy,
If you have any pics of your bamboo harvest and grove I'd love to see them. Also feel free to show pics of your works and tinkerings in the bamboo crafts gallery (http://www.bamboocraft.net/gallery)

Phyllostachys nigra 'Bory' (http://www.bamboocraft.net/bamboo/showgallery.php?cat=607) is a very pretty bamboo. Unfortunately it has the same reputation of other nigras, especially as diameters get larger, of which a percentage of culms will have a propensity to split.

My first suggestion is to humour the bamboo when working with it, but refrain from performing high class culmedy acts to avoid getting a side splitting reaction of popping laughter. Poor taste jokes like this might actually help the bamboo build up a tolerance to cracking up. ;)

In other words, getting to know the boo's personality can help in understanding or determining a culm's potential to cracking up.
Often events during the life of the boo affects it's characteristic properties.
For example, bamboo culms will bend and sway in the breeze, but high winds and heavy rains, ice and snow loads can cause culms to bend excessively and might result in minute fractures, that are only revealed as a crack during it's after-life as a dried culm.
In this respect, growing your own bamboo and knowing more about each culm during all phases of it's life through to harvesting and processing is very helpful in making decisions on it's suitability for an intended use.

Back to your actual question ...
I would like to know which technique would result in fewer cracks - heat treating alone or heat treating and drilling out the cores?

My thought are that punching out the node stops/diaphragms can produce a more even or consistent drying of the bamboo which could result in a more even distribution, or less concentration of stress points within the bamboo, and less chance of degradation of the natural 'glues' binding the fibers at any given point.
But there are number of various controllable and uncontrollable factors involved. In my limited experience both methods can produce satisfactory or contrary results.

It's been a long time since I've had some Bory to play around with.
I would suggest to try out both methods and keep us tuned in on the results.

Here's another thread that may be of interest:

Black bamboo (Phyllostachys nigra) for making flutes? (http://www.bamboocraft.net/forums/showthread.php?t=2403)

Cheers,
Mark

[Pondman]

Mark - Thanks for the useful info and the humor! Here are some photos of the 'Bory' Grove.

http://www.bamboocraft.net/bamboo/data/607/thumbs/Bory-Grove-01.jpg (http://www.bamboocraft.net/bamboo/showphoto.php?photo=4432&cat=607&ppuser=2542) http://www.bamboocraft.net/bamboo/data/607/thumbs/Bory-02.jpg (http://www.bamboocraft.net/bamboo/showphoto.php?photo=4431&cat=607&ppuser=2542) http://www.bamboocraft.net/bamboo/data/607/thumbs/Bory-03.jpg (http://www.bamboocraft.net/bamboo/showphoto.php?photo=4430&cat=607&ppuser=2542) http://www.bamboocraft.net/bamboo/data/607/thumbs/Bory-04.jpg (http://www.bamboocraft.net/bamboo/showphoto.php?photo=4429&cat=607&ppuser=2542) http://www.bamboocraft.net/bamboo/data/607/thumbs/Bory-05.jpg

(http://www.bamboocraft.net/bamboo/showphoto.php?photo=4428&cat=607&ppuser=2542) http://www.bamboocraft.net/bamboo/data/607/thumbs/Bory-06.jpg (http://www.bamboocraft.net/bamboo/showphoto.php?photo=4427&cat=607&ppuser=2542) http://www.bamboocraft.net/bamboo/data/607/thumbs/Bory-07.jpg (http://www.bamboocraft.net/bamboo/showphoto.php?photo=4426&cat=607&ppuser=2542)

[Mark Meckes]

Hi Andy,
Nice pics! And a great bamboo with lots of character.
Heat tempering it really brings out the contrasting tones, especially when the white waxy surface coating is melted away.
Culms that do split make very attractive splits, and if they only split open in one place they make nice border pieces that split bamboo can be inserted into perpendicularly.

Yes, your cracking reference reminded me of this vain attempt at poetic prose which I managed to dig up from the past ;)

http://www.bamboocraft.net/workshop/data/2/thumbs/1Mvc-183f.jpg (http://www.bamboocraft.net/workshop/showphoto.php?photo=665)
- Aged Moso Splitting open. (Phyllostachys edulis, syn P. pubescens)

POP! PoP! Did you hear that sound?
That's bamboo splitting it's sides open with laughter!
It's releasing tensions acculmulated during life,
and making preparations for the bamboo hereafter!

It's not odd, when a culm splits open,
that it can actually can make bamboo stronger.
Like opening your arms to hug someone,
the `arms' open up, and the back becomes tighter.
So too, bamboo gains renewed strength after splitting,
providing new uses for the crafter to ponder.

At harvest, the life of bamboo is renewed,
full of purpose, applications and uses.
But there culms a time when bamboo can relax,
and return to earth as food for future generations.
Mark

[laowho]

Pondman,
just finished learning how to press my Bori (thx...didn't know what i had!) into four-foot ovals w/o splits or cracks. you must spray w/ room temp water after combing (torch heat f/ bottom to top) until the heated section is muffin-warm. and don't heat to more than untouchable, wh/ is just right. this steaming (combed sections beautifully drink the water) also keeps your dark tones down/lets you choose from more shades.
laowho