ohhhhh! The Carnage!!!

[Easternarcher]

I was in final stages of tillering this Boo backed IPE R/D. The static brace looked real good I thought. 5.5- 6" brace with 1/8" positive on upper limb. Don't have a pic of the unbraced profile but it had 1" deflex with 2" reflex in front of riser.
Had it drawing 50lbs at 25in. on the tree when I thought I heard a tick sound just as I was reaching 25" for the second time... Just as soon as I heard that sound, I heard a bigger BANG! The upper limb let go right thru the middle.(The limb on the right side in the pics).
I thought maybe you more experienced Bowyers could point out a flaw or two? Maybe bad boo, bad IPE? Couldn't see anything myself. Well, this was supposed to be a birthday gift soon enough, just means I'm gonna have a few late nights getting another ready.
Sorry Tony!

[mullet]

 Looks like it broke in the runoffs in the Ipe.

[Easternarcher]

Looks like it broke in the runoffs in the Ipe.

Mullet, I guess that's possible. I looked again just now and in the pic.....in the upper right, there was an section of lighter coloured wood and althought it did run out some, it wasn't as bad as the lower limb run-out. but I guess that works for an explanation. I'll just have to be more careful on the IPE I use from now on.
 The break starts at a run-off but cuts across grain  most of the way.  I didn't think that grain would have made a big problem since it was backed with boo tho.

[Pat B]

I have to agree with Eddie. The grain angle is too sharp, even with a boo backing.

[knightd]

I agree as well.. just out of curiosity is the break right where your clamp was??

[Parnell]

I've had several that did the same but I was starting out and backing with maple.  Probably not the best choice.  The breaks did look the same.  I started getting picky about a better part of my Ipe board (grain) and using hickory backing.  Still trying to figure out how to prepare bamboo...

I know the ominous sound, well.  Ugh!

[medicinewheel]

There are also marks in the bamboo right where it broke, that might indicate some weak spot; maybe that added to the runoff problem.

[Easternarcher]

I agree as well.. just out of curiosity is the break right where your clamp was??

hmmmm, I just checked that Dave....no the clamp was 2 in. farther out. Here's a pic of my form...the break was 12-14" from center. Clamp was either at 16 or 18" from center. Glued up without the riser in place of course.


Is it possible I over-dried the boo in my hotbox or dried it too fast? Would that add to the problem?
Dang...I'm gonna have to shorten that plank and splice the rest together for slats.
More work, but I'm learning. I liked how this was turning out too!

[Marc St Louis]

Looks to me like the Bamboo failed

[Tom Leemans]

just curious, how thick was the boo?

[ShinneryOak]

I posted a few days ago about the same kind of thing. I've tried Ipe a few times (unbacked) and the stuff I had failed like this, where the grain ran off. I just had another one blow up, this one was a backing of ipe on osage, the whole thing broke thru at the handle, but still seemed to follow the runoff. That's why I have my first order of boo in the mail, thought it would solve this!! Marc, do you think the boo "overpowered" his core? 

[Tom Leemans]

That's why I asked how thick the boo was.

[DanaM]

I feel your pain I just broke one today. I'll get pics up when I can

[Easternarcher]

That's why I asked how thick the boo was.

I'll check it when I get home tonite.

[knightd]

Ive made BBI that the boo is thicker than the core and havent had any trouble..