I am not a scientist. I think that the scientific method is one of the great achievements of mankind, but, I would never claim that I'd worked it thoroughly enough to deserve the designation. But I do want to know more about what I do, so the experiments march on.
Lately I've been thinking about bending. Perhaps it was having to bend some walnut after a recent bad experience that got the juices flowing. I read literature that remarked on the moisture content of steam as it related to wood bending and the concept that steam piped into a box might be lacking moisture. Of course, heat is the primary element in bending wood, but moisture is the conductor. As I understand the concept, the moisture can drop out of suspension in the steam en route to the box and what ends up making it into the box could be heat, but not as wet as it could be.
So to see if my steam needed wetting or if there was any difference in my bends, I attached a reservoir below my steamer that the hose from the steamer runs to so that the heat must pass through water as it enters the box, ensuring that the moisture content was at it's highest.
When I start up the steamer, the steam boils the water in the jar. So far, the results have been positive enough to warrant further testing.
Here are two bends. The same wood, air dried walnut, steamed for the same amount of time, 90 minutes. The piece that bent didn't raise a single fiber even though the fibers ran out the side more dramatically than the failed bend. And yes, the only difference was that one was steamed with the reservoir and one without. Of course, the successful bend was with the reservoir, and as far as free bending walnut, it's the tightest bend that I've done.
I've done other samples and gotten similar results. One factor that interests me is how this effects long steam times. Imagine that the steam isn't adding enough moisture, this may never be an issue with green wood or short steam times, but for working air dried or even kiln dried, this could make a difference.
Like I said, I'm no scientist, and I'd love to here from you about your ideas or experience. I am planning some tests with kiln dried white oak that I'll post soon.