Kirk,
Old form
Butt wedge 5/16-0 in 11.5"
Tip wedge .050-0 in 6"
Laminations 30" (Usually trimming off 1.5"-2" of the tip)
Typical stack (.245) for 45@28-62" at 13.5" on a 18"riser:
Clr G .040
Ven .020
A-boo .060 PAR
A-boo .073-.001 TAP
SC .012
BG .040
New form (These heavy limbs)
Butt wedge 5/16-0 in 11.5"
Tip wedge .030-0 in 9" (wanted the tip wedge to thicken the base of the curve a little more for stability)
28" laminations
This stack (.235) came in at 75@28-61" on a 17" riser
Clr G .040
Ven .020
F-boo .055 PAR
F-boo .068-.001 TAP
SC .012
BG .040
The new limb profile sitting above the old limb design in pic.
I'm just realizing in writing this out how much I shortened the working limb from 12.5" to 7.5". This may have been a factor
I do need to get a string tension measuring system going. I've heard you talk about that since I've started, and it make sense to me. These limbs have a crap ton of tension as I've never had a bow so hard to string and have such a high note when the string is plucked.
I think you may be right about this fossilized bamboo having shorter woven fibers vs vertical grain with elongated fibers...... But..... Under glass this stuff has proven to be excellent material so far and has decent test results vs the action boo i've used for so long.
That makes me wonder if your limb didn't let go on the Belly as there wasn't any glass holding it down from buckling under compression. I think the glass spreads out the pressure over a longer surface area and won't allow a pinpoint fracture or failure.