Mujitsu and Tairaku's Shakuhachi BBQ

I just got a new batch of bamboo and most of the pieces are great and I thought that I would try my hand at bending, just to see what happens.  I have been reading Elmer Takeo Kudo's kinko making book and am following the process described in the book, and after I have heated the bamboo I go to bend the stock on the apparatus..... nothing.  I have put all my weight on the stock, reheated time after time and still..... nothing.  I can't seem to figure out the problem.  Could the bamboo just be resistant to bending?  I am at a loss, and help would be greatly appreciated

Ben