Thursday, February 18, 2010

G8 and G9, and reed relaxation

Wired G8 and G9, the ones I tried to make wide. When I first put on the wire, the reed went onto the mandrel all the way to the handle. After heavy post-tube-formation beveling, and really tightening the wires (2-4) hard, they still fit on the mandrel about 4-5mm past the mark. I suspect that these guys will shrink little when they get soaked, and even if they do, they will still fit far onto the bocal. So, so far, this experiment is a success, in that yes, a wider reed makes a bigger tube. What it'll do to tuning I have no idea -- even if the blade is closer to the rest of the bassoon, its larger internal volume may compensate. I'll find out in awhile, I guess.

Also moved along the next two reeds, these shaped normally. These had been soaking for almost three weeks at this point. I'm not exactly doing two per week, but then, I'm not really consuming two per week either. Besides, letting reeds relax for weeks after forming tubes is commonly recommended. Usually people have mandrel tips for in process reeds to sit on, but I don't, so I'm starting a small collection of wired blanks, just sitting on my desk. I guess the idea is that polymer viscoelasticity allows the stress at constant strain to be gradually reduced over time. Googling led me to a 1954 Nature paper, with the following figure showing the force required to maintain a bend in a beam of hoop pine, under various conditions. Note the time scale: it goes from one minute up to two months. It hasn't stopped changing, but presumably the author got bored after that. But it does demonstrate that yes, it's reasonable for cellulosic material to creep for a period of weeks, so letting the reed sit makes sense.

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