bamboo backing question

[ravenbeak]

Hey guys,
I am looking for some insights to an issue i am having with some bamboo backing, I know there is a lot of experience on here

The bamboo is cracking vertically down the center of the bamboo, it has happened on several bows now.  The glue ups had been tillered and oiled and then these cracks show up.
I am wondering if it is a moisture issue with the bamboo being too wet (stored outside) or drying oil too close to the woodstove,  or is the bamboo more sensitive with the rind scraped down

Looking forward to figuring this one out, thanks for the help

[Gordon]

I've never had that happen and I always scrap off the rind. Like you I suspect its a moisture issue.

[wizardgoat]

jamie, I've heard that bamboo can soak up moisture and should be stored inside.
Probably the rapid drying from your wood stove is causing the checks, that would be my guess

[mikekeswick]

Moisture content is the problem. It can be very frustrating....it will check much easier than the average backing wood for sure. The only way round it is to store your boo inside and keep it's moisture content under 9 - 10 %.

[sleek]

If I rapid dry osage it does the exact same thing to me.

[Pat B]

The good part of this is it shouldn't affect the performance of the bow unless, like with a wood backing the check(s) run off the bow. Other than that it is probably just cosmetic.

[Trapper Rob]

I had one do the same thing I put super glue in the cracks.

[adb]

Bamboo is great backing material, but for the reason you describe, I don't use it anymore. Vertical drying checks are just cosmetic, but I've had people freak out because "there bow is broken!"
Bamboo is very hygroscopic, and will release and gain moisture at a much faster rate than the wood it's laminated to... hence the checks. I've also found over the years that bamboo can be very unpredictable. Perfect bow, perfect design, perfect tiller, but the bamboo just fails... and usually in dramatic fashion. It's also labour intensive. Starting with something that's round and having to make it flat for laminating is extra work. Long story short, bamboo gets little use in my shop anymore. Maple and yew are a match made in heaven IMO.

[ravenbeak]

Thanks everyone for the feedback,

I believe it to be a moisture issue,  I have since moved the bamboo stack into the shop to keep moisture levels lower.   I also don't believe them to affect performance,  but I can't stand looking at them.

cheers, 

[DC]

Hi Jamie
You should have left them out until this cold snap passes through. Some nice dry (cold)air out there.
Don