I started with a stave of Red Oak. A pyramid bow, 42 mm wide at the center, and just under 1/2 thick. It should have been a doddle. 90 minutes after starting, I did indeed have a shooting bow. Problem was, it was only 19 lb at 28 inches, and all I'd really done was remove the saw marks from the bandsaw to tiller. Obviously, this particular piece was nowhere near as stiff as other bits of Red Oak I've used.
I thought I'd try something new. So I backed it with a bit of Elm and glued it into 2 inches of reflex, cooking it for two hours. It kept one inch of this and I left it for the rest of the afternoon and overnight to relax. I backed it to increase the thickness. I glued in reflex to increase the stiffness-per-thickness. Doing both of these things would allow me to begin again with a thicker stave that I could tiller down to a more respectable draw weight.
Things were going well. I even dusted off the spokeshave, which I can't typically use with the usual Spotted Gum and Ironbark. It was a delight to be removing curls of wood instead of dust.
I'd just progressed from 20 inches of draw and was going to measure the draw weight at 22 (This is at 20, and I had fixed the tiller before progressing, but hadn't photographed it).
All of a sudden there was an enormous bang. A something hit me on the back, and there was a clatter about the workshop as fragments rained down.
It was the limb on the left in the above picture that broke.
Now...this is a classic tension failure. I had not expected this. If anything, I would've guessed that the tension-strong Elm would cause the sub-standard Red Oak to collapse. Yet, this catastrophic failure happened. At a guess, I'd say either the cooking yesterday dried the Elm too much (shouldn't have) or there was an unseen flaw in the backing. Which is a pain if that's the case, because the grain was straight with no visible flaws. Which makes repeat offences nigh impossible to predict/avoid.
As an aside, my right shoulder, wrist and elbow were horrendously jarred by the explosion. At first I couldn't understand why, as the draw force was only about 30 lb. But then I thought if someone wolloped me in a bony joint with a wood mallet with 30 lb of force, that'd probably feel pretty unpleasant too.
It's pretty disheartening to break a bow, especially when it should be so easy. Keep plugging on though, eh?
