Sapling -- I sure wouldn't make it my first choice for a sapling bow, though. I'd prefer just about anything else. I just did it for this contest. It's quite soft, so you need very sharp tools. Having a sharply cambered back makes it even harder, and I really didn't think this was going to work out.
Some tips: This second time around I didn't hollow it. I now think hollowing of this wood just concentrates the strain at the edges and over-flexes them. Second time around, the bottom was just tillered flat.
Heat tempering and forming seems to work with Eastern cottonwood.
Length is tied to draw weight on this wood and sapling dia, and there's probably a limit to it. Might even be close to 40#. I started out with a longer stave, but once I got it bending I was only getting about 1 lb/inch draw.
Leaving the wood thicker would have created set or fretting. Incrementally piking gradually increased the force/draw to closer to 2 lb/in, without seriously increasing stack, or set, and I finally settled on 63" and 41# @ 28". On the other hand, I think if I'd gone much farther with piking, set would probably negate any increase in draw weight. I think I pretty much got the most I could out of this particular cottonwood sapling. If you call that a sweet spot, I think I hit it.
Anyway, it's a good challenge, if you take it on, and a stave from a bigger tree would probably be easier. Certainly teaches a lot to work with a marginal wood.
