Drying Bamboo: Moisture Stains

[Mark Meckes]

Ocassionally, a culm, in the drying process will deveop moisture stains.
http://www.bamboocraft.net/workshop/data/2/thumbs/1Mvc-151f.jpg
In this picture (http://www.bamboocraft.net/workshop/showphoto.php?photo=633) these Phyllostachys aurea poles had been drying upright, outside under the shade of a chinaberry tree during a hot Texas spring/summer for 4 about months.
The culms were not water-filled, which I've never observed in this part of Texas.
Is there a name for this effect? It imparts amazing patterns, which can add beauty to the design of a product.
Up to this stage of drying, they don't seem to diminish in strength, but if they remain in this state for much longer, the surface becomes bumpy, and...
http://www.bamboocraft.net/workshop/data/2/thumbs/1MVC-061F.JPG
the `sesame-seed effect' (http://www.bamboocraft.net/workshop/showphoto.php?photo=544)begins to appear.
Control of humidity, heat and air circulation and drying rate are factors that produce effects, desirable or otherwise.

http://www.bamboocraft.net/workshop/data/2/thumbs/1Mvc-152f.jpg
Patterns on Split Pieces (http://www.bamboocraft.net/workshop/showphoto.php?photo=634)
when I split apart this culm, a misty moisture sprayed out.
The culm interior was still free of any `mildew', though the inner wood had changed from ivory to a tan/beige colour.
After air drying for a few days, the surface patterns lightened slightly.
Mark

[Mark Meckes]

Here's another example of stain, or discoloration of the inner walls of the bamboo - Phyllostachys edulis (aka pubescens)
I might stain or paint or dye the inside of this unfinished roly poly froggy..., maybe even engrave or burn on a design (pyrography).

I usually prefer to leave the bamboo in it's natural color, but if the inside has a stain that is not attractive (to my mind), then it becomes an opportunity
to experiment!

Mark