Dave,
I do not know of any way to prevent the bamboo from lousing the green color but here is a couple of ways to stain the culms. From the TBS group emails.
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The Roy Rogers way:
I've spent a lot of time trying to figure out how to stain bamboo culms.
The basic problem is that the culms are very resistant to absorbing any
moisture, which means that the tint/stain won't penetrate the culms. I've
tried various liquid solutions, such as alcohol, bleach, stripper etc, but
nothing worked that was easy and simple to do.
The only effective way I've found to get the culms to absorb tint/stain,
but not an easy way, is to sand, sand, and more sanding. If you don't sand
enough, then the tint/stain doesn't really absorb into the culm and you can
easily scrape it off with your finger nail.
I use an electric sander, but the flat sander surface and the round culms
make for a lot of long tedious sanding time. I tried a 3D sander, but it
didn't work well and the wheels kept coming off.
Once I've sanded, sanded, and more sanding, I apply tint/stain, once a day,
over a 4 or 5 day period. Once tinted/stained, then I put about 3 coats of
Wipe On Poly, which takes about another 3 days. This is definitely
something I would not make and try to sell. Labor and time intensive.
I'm working to see if heat will have any real effect on the process. I cut
7 B. v. Buddha's Belly 3 inch culms into 15 internode sections, without the
nodes on either end. The sections were mostly, but not completely dry. I
put them in the kitchen oven for about 5 hours at 170 F degrees. Then I
gradually moved the temperature up to 250 F degrees over the next 5 hours.
I'll start this weekend to see if I can figure out any positive effects
from the heating process. If there is a positve effect, then the next
thing is to figure out how I can get a 6 foot culm into the kitchen stove.
Roy Rogers
Tampa, Fl
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The Carole Meckes way:
If you take an older naturally weathered piece of bamboo that does not have
much "skin" left on it and stand it upright in a container that has some 'oil'
in it and let it stand for a period of time, adding more oil when needed, the
oil will travel up the culm and transform and stain it - it will also add some
weight to the culm.
I've tried this inside the house, where I can monitor the results easier and
have been fascinated by watching the color of the culm change over a 6 week
period as the oil gets absorbed and travels up the culm. I usually squeeze
some cocounut suntan oil into a yogart container and lean the bamboo culm
again a wall on top of counter so that I can monitor it periocially and have
to add more oil several times as it gets absorbed by the bamboo. Rhizomes are
also fascinating to do this with.
(no sanding needed - but it does require time!)
Carole
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You can see some of Roy's culms at
http://www.bambooweb.info/images/crafts ... s_rack.jpg
Bill