I've got the bamboo backing blues

[DCM4]

These all natural bows are fickle lak wimmen, and occasionally will torment you just to make sure you remember why this game is so interesting.

That said, I do stay off the nodes when finishing boo.  But I've had it fail with the rind and nodes still untouched.  I'd chalk it up to bad luck, natural variation in the material, and perhaps a bit of treading too close to the edge. 

I've used URAC as old as 2 years or more Rich.  But I keep it sealed in the fridge and only take out small quantities at a time to work from.  Be mindful of how old the product may have been before it found it's way to your hands.

[Rich Saffold]

David, I couldn't agree more, nothing is ever a guarantee with these bows, and it does keep things interesting.  If we were all afraid of failure we would just make pipe straight selfbows with a hide backing

Marc, I have plenty of bows out there with the rinds scraped and sanded off.  I don't take rind removal as an absolute cause at all, but as you can read here many others have experienced the same problem. I don't think these problems arise from the back fibers being violated as much as just getting exposed, and this may be fine for some bamboos and not for others. Which is what I found. So I just don't bother with it, and most of what I get to cut has enough markings to make it a unique bow.  I have seen more than one thoughly sealed bow get very dry in the desert so I never view any finish as a remedy to the conditions it may encounter. Like the super dry air in the cabin of a jet going halfway around the planet .
 

Getting bad bamboo is the worst scenario since nothing can be done to rectify this, and why I cut poles from as many locations as I can just to avoid this situation.


Rich-"midnight bamboo supply"

[dragonman]

Gordon,  you said you used bamboo planks, I'm interested what are these? Also , was the bamboo extremely dry (low moisture content) ? this might account for it?? I beleive its best to leave rind and nodes alone , the rind gives added protection and the nodes look good, why risk it just for looks??

[zenmonkeyman]

I'm a noob and know zero about bamboo, but I think I'm seeing something here, possibly.  If it's always the upper limb that splinters, and the bottom of the bamboo is on the lower limb of the bow, and I'm going out on a limb here, but I'm guessing the splinters always point in the same direction?  This would suggest to me that the bamboo should always be spliced with the bottom end of each piece at the nocks.  Does that make sense to anybody?  Like the bamboo is stronger if the bottom is pulled towards the top rather than vice versa.

[Gordon]

Dragonman,

The planks are actually called Bamboo Slats. The ones that I purchase are made of large diameter Moso bamboo and are milled flat on 3 sides so they can be screwed or nailed onto a surface such as a ceiling, bar, or counter top. I don't believe lack of moisture is an issue because it is quite humid where I live in the winter and bamboo readily absorbs moisture.

Zenmonkeyman,

The splinters were all in the same direction, but I do not know if that is just a coincidence. I think your theory is worth testing though.

BTW, I am attempting to repair the latest splinter.  My plan is to super-glue the splinter down and wrap the area with a sheer silk strap that is saturated in TB3. I will then glue a thin patch of rawhide over the end of the splinter that rose and wrap that with serving thread. I'll make a matching wrap on the other limb for looks. I don't know if this will work, but I have nothing to lose.

[Gordon]

The repair seems to be working. I had to retiller the bow and lost 5#, but it's holding together. I can't say I care much for the look of the patch, but at least I salvaged the bow. I'll probably paint this one all black to obscure the patch and use it as a field bow.

[Gordon]

Well, the patch is holding fine, but now the bamboo on the other limb lifted a splinter. I give up...

[adb]

You know, Gordon... I feel your pain. I went throught the same thing with bamboo about a year ago, and as a result, I just don't use it anymore. Lifting splinters, cracking, checking, blah, blah, blah... it's just too dry here for it, and it cracks into bits. I even had a tri-lam ELB with bamboo as the core material, and it cracked and checked too!
I've been using ash, maple, hickory, elm, rawhide and sinew as backing material, with no issues. No more bamboo for me... it's too frustrating, and too labour intensive ta boot. Blaaagh 

[Rich Saffold]

I'd pop the backing off and back it with a slat of Ipe about 3/16th's-1/4" thick, and get it shooting again.. Gordon I hope you try it because it was this same bamboo scenario which made me try it the first time, and it was an epiphany of sorts from how easy it was to how the bow performed.. And shaping the backing to fit is kinda enjoyable as well.


Rich-

[Gordon]

adb,

I'm about ready to chuck my stash of bamboo into the dumpster - I would have never guessed that bamboo could be so fragile.

Rich,

That's a really good idea - no sense wasting a perfectly good core and belly.

[adb]

adb,

I'm about ready to chuck my stash of bamboo into the dumpster - I would have never guessed that bamboo could be so fragile.

Well, I gave it up. I'm not saying you should, but it doesn't work for me.

[Gordon]

I'm not going to give it up entirely - I have too much yew lumber in my garage to do that. But I am going to discard my current cache of bamboo. I don't trust it anymore.

[Dean Marlow]

Gordon I was wondering if there is any way you can do a bend test on your remaing boo slats to compare one slat from another batch? Dean

[PatM]

It is worth pointing out that Moso is notorious for being the weakest bamboo, particularly at the nodes. This is the same thing that Dean Torges described before he switched to superior types of bamboo.

[Gordon]

It is worth pointing out that Moso is notorious for being the weakest bamboo, particularly at the nodes.

It's interesting to note that only one out of the 4 failures that I experienced actually happened on a node. This last one is particularly vexing. The splinter started midway between two nodes, there were no obvious nicks on the back and the backing was not particularly thin at that point. And it happened after previoulsy putting at least 100 arrows through the bow. I'm beginning to wonder if these failures might be related to the method I am employing to heat cure.  With this last bow I put on a thin coat of Tru-Oil directly on the wood to seal it not realizing that the oils in Ipe would inhibit the finish from drying properly. So I kept the bow in front of my fireplace for the better part of a day until eventually the finish cured enough to handle. The backing failed promptly after that.

I had one more bow in the queue so I glued it up this morning and carefully wrapped it in plastic film to prevent moisture from escaping as I cure it in front of the fire. I hope that's it because if I wreak one more bow I think I'm going to break down and cry