Within a period of a few month, my friend Chris who's double curve bamboo back and belly won Bow of the Year in 2007 had bamboo failure on some 4 or 5 bows! Chris is an experienced bowyer, he works with bamboo since years and has made lots of bamboo backed bows.
Some of the bows were new, others had already been shot for two years.
None of the bows were highly stressed, some reflex/deflex (bbo, bb ipé) others dbl.curves (bamboo back & belly); one bamboo backed ipé 68" ntn failed when a guy with a short draw pulled it.
The bamboo used was from various sources but all high quality with no problems visible, Madake and Moso (I guess).
The backing stripes were mildly tempered.
All failure happened in the nodes, the nodes were not worked down, just sanded.
Two of these bows were permanetly stored in rooms with no Winter heating at all.
As far as known, all bows broke during the pulling, not after release.
All bows were shot with 16 strand fast flight flemish strings.
Does anyone have any idea of what the problem could be??
Thanks for all replies!