Last night I was tillering a birch board bow and it was looking great. I had used the long and short tillering strings and it had great shape and I was getting really good limb movement. I went to brace the bow and without warning it came apart on me.
I'm guessing I was just going a bit too fast and my string may have been too short for that initial brace, but I know I had more limb movement on the tillering tree than what that string was asking of it. :confused:
What most likely went wrong? Is white birch (paper birch) a decent wood for a bow? It looked promising while I was working on it. The wood was native Alaskan birch and was kiln dried. I'm thinking about starting another, but if it is a problem with the wood, I won't waste my time.
What method were you using to brace the bow? If the push/pull, you may have put uneven pressure and overstressed the bow. Birch isn't a very strong in tension wood so over stressing one area could result in a break.
You have to educate the wood and early in the process, uneducated wood can cause problems if pushed.
That is probably what happened. I wasn't using my stringer since it was moving really well and I hadn't worked on the tips yet...Lessons learned.
I got another piece of the same board today to give it another try. I usually flex the bow about 30 times every time I remove wood while tillering but I will definitely spend more time working the wood before I go to brace it.
How is the grain on your board. You may want to back it as insurance. Silk, linen or rawhide will work for a backing.
I say 98% of board bows need to be backed.
A properly chosen, straight grained board need not be backed because it is a board. A backing is suggested for beginners though and if the grain is not good. It's about the angle of violations and the draw weight wanted. There's more on my site. Jawge