Sgian Dubh
Established Member
I find it interesting that you describe knowledge of timber technology and the mechanics of wood bending as "trite", but I guess you find it all pretty boring old hat, been there, done that, got the T shirt, etc, ha, ha. Personally I am fascinated by the subject and, having studied it in some depth for the last thirty odd years, I am always taken by how new and interesting I find so many elements of the topic.
Anyway, I didn't say it is well known that high moisture content woods bend more easily, but that paraphrasing of what you said is correct. I said "It’s well known that steam bending is easier to do with green wood, i.e., wood at FSP." I should perhaps have expanded that to say that green wood means in this instance freshly felled wood, which although also wet bends more easily than wood that has been dried and then rewetted back up to FSP, or above.
I went on to say, "wood kilned to 7% MC, the north American standard has become much stiffer and, due to a form of hysteresis, it is quite difficult to make wood soft and pliable again once it has reached this level of dryness and stiffness." What I was trying to say, but perhaps didn't make clear, is that once a piece of wood has dried, hardened and stiffened because of the low moisture content it has reached, eg, 7% MC, that due to a hysteresis effect it will never again be as soft and pliable as it was when freshly felled, even if you get the cells fully loaded with bound water.
If you take a freshly cut slender hazel branch it will free bend and conform to a particular radius. Take another branch as near identical as possible to the first, and instead of bending it green, dry it, rewet it and free bend it. It won't take as tight a bend as the first branch. Granted, you are not likely to find two branches that are exactly the same in every characteristic, so the experiment is not absolutely scientific; but that is my experience and it matches the experience of other woodworkers.
However, your questioning has prompted me to revisit a text I'm working on, from which my responses to you were lifted pretty much verbatim, and do a bit of rephrasing and add a bit more explanation to try and eliminate any misunderstanding of the point I'm making.
Edit. In answer to your ending question, yes, wet wood does transfer and hold heat better than dry wood because the water is there, but it is the stiffness that dried wood develops and never entirely loses even when rewetted that makes it more difficult to bend, not necessarily the dryness itself. I hope I've said that so that my meaning is clear. I guess I'll find out later. Slainte.
Anyway, I didn't say it is well known that high moisture content woods bend more easily, but that paraphrasing of what you said is correct. I said "It’s well known that steam bending is easier to do with green wood, i.e., wood at FSP." I should perhaps have expanded that to say that green wood means in this instance freshly felled wood, which although also wet bends more easily than wood that has been dried and then rewetted back up to FSP, or above.
I went on to say, "wood kilned to 7% MC, the north American standard has become much stiffer and, due to a form of hysteresis, it is quite difficult to make wood soft and pliable again once it has reached this level of dryness and stiffness." What I was trying to say, but perhaps didn't make clear, is that once a piece of wood has dried, hardened and stiffened because of the low moisture content it has reached, eg, 7% MC, that due to a hysteresis effect it will never again be as soft and pliable as it was when freshly felled, even if you get the cells fully loaded with bound water.
If you take a freshly cut slender hazel branch it will free bend and conform to a particular radius. Take another branch as near identical as possible to the first, and instead of bending it green, dry it, rewet it and free bend it. It won't take as tight a bend as the first branch. Granted, you are not likely to find two branches that are exactly the same in every characteristic, so the experiment is not absolutely scientific; but that is my experience and it matches the experience of other woodworkers.
However, your questioning has prompted me to revisit a text I'm working on, from which my responses to you were lifted pretty much verbatim, and do a bit of rephrasing and add a bit more explanation to try and eliminate any misunderstanding of the point I'm making.
Edit. In answer to your ending question, yes, wet wood does transfer and hold heat better than dry wood because the water is there, but it is the stiffness that dried wood develops and never entirely loses even when rewetted that makes it more difficult to bend, not necessarily the dryness itself. I hope I've said that so that my meaning is clear. I guess I'll find out later. Slainte.
