Missed weight

[jsweka]

That's interesting Jess.  You know, that first bow that I got that stack from was my first experiment using 0.040 glass in a straight limbed bow instead of 0.050 glass.  I made a semi-educated guess on the stack, used 4 actionboo lams and ended up at 54# - only a couple pounds less than what I wanted.  That was the only bow I've ever made with all actionboo lams.  Maybe I just got lucky on that first one.  The current bow only uses 2 actionboo lams.

[jess stuart]

John, I can't say how much the .050" vs .040" glass would change things.  I am fairly confident .010" of glass would have a greater gain than .010" of corewood but, can't say from experience.  I have very rarely used .050" glass and it was years ago, .040" works well for the weigth and types of bows I build.  
I never noticed a signifant weight change using other types of corewoods, (Red Elm, Walnut, Maple. Black Locust etc.)  only when I use aboo do I have a weight decrease with the same stack.  I don't know for sure what conclusions to draw from that but I do have some.  Interesting to find out someone had a similar experience.

[Mike Mecredy]

All bamboo lams in the same stack thickness will be less draw than one with wood in the stack of the same thickness.  Plus I've never noticed walnut lams making a lighter bow, but bamboo, action or natural will.

[jsweka]

Thanks Mike.  You've certainly got more experience at this game than me.  Given what you and Jess have said, I guess maybe that's the basic reason for the difference - all actionboo vs. actionboo & walnut.  Won't make that mistake again.

[MoeM]

Wasn`t there a testseries by Kenny that showed nearly no difference beetween several corematerials?
(guess a friend told me about once)

[jsweka]

Moe - Yes.  And there wasn't much difference.

     

[Mike Mecredy]

If a customer insists on me using bamboo or action bamboo as the laminations I generally add .010 to my total stack thickness to get the wieght I need.  I don't addjust for different types of wood (bamboo isn't wood) or different thickness of fiberglass.