Stack Question for the Boyz ?

[Forwardhandle]

I have been missing my stack calculations 8-12 lb lately ,I'm doing some figuring this morning and I want to drop the glass by .020 so my question is does dropping the glass thickness have the same effect as dropping the core thickness in your guys exsperience ??

[Roy from Pa]

I would say dropping the glass thickness will drop more weight than dropping the core thickness.

But heck I don't make gwass bows:)

[Forwardhandle]

Well I dont know but here is my known stack

68" D/R
Wood .235
Carbon .020
Glass.  .080

Total stack = .335 = 52lb @31
Including SL in stack

This is my re calculation for 64" D/R

New D/R 2 Design 64" 50lb@31"
Wood lams .225
Glass.          .060
Carbon.       .020
Stable core .015
                  T=0.320
Including SL in stack

[Roy from Pa]

Hang on till old Sticky-pops crawls out of bed, he will know...

[Crooked Stic]

Ok I am up now Elroy.  My experence has been reducing glass is gonna be more than the wood. But not much. Design factors in to

[Roy from Pa]

Morning Pops..

[Forwardhandle]

Ok thanks Mike all things considered I'm dropping total stack .325 that's about a 5 lb drop on thickness less what ever the glass differential is even if it was 3 to 8 lb it should put me in 42 to 50lb range and that's ok for what I'm looking for begers can't be choosy when trying new materials 

[Bvas]

Ok thanks Mike all things considered I'm dropping total stack .325 that's about a 5 lb drop on thickness less what ever the glass differential is even if it was 3 to 8 lb it should put me in 42 to 50lb range and that's ok for what I'm looking for begers can't be choosy when trying new materials 

How much are you dropping the stack?

[Forwardhandle]

Thanks Brad I'm actually bumping up .005 from my previous stack calc for a total of 0.325  decreasing .010 from the 68" stack if my math is right !

[Bvas]

On my 56-60” d/r form, .005 equates to about 5#. Im guessing a little less on the longer bows like you are building, but probably still about 4# per .005.
So I’ll say 8# plus an additional 2# for thinner glass for a total of 10# drop.

Then I’ll guess you should gain about 4# for every 2” shorter. So you will gain 8# back with the 64”.

My guess is you’ll hit 50# with the .325 stack. Final answer. lol

But what do I know, I missed weight by about 10# on my last build. 
But I also think switching from Gordon’s to bear paw glass had something to do with that

[Forwardhandle]

Well this one drops 5lb per .010 according to Kenny's blue prints using .040 glass & no carbon so I'm guessing I'm in the ball park give or take 10lb  the real question is how much of a drop using the .030 glass but I guess only one way to find out 

[Mark R]

I'm thinking your performance may lack with the thinner glass. Plus your adding another glue line with the stabil core, but really can't be sure until its tried, good luck and let us know.

[jess stuart]

I glued up a 54" statistic recurve so not the same thing.  It came out 56 rough and finished up at 51.  I then glued another set of limbs exact same overall stack thickness but .010 less glass on the back.  It will be next week before I get it profiled so, we might learn something.

[jess stuart]

That's a static danger auto correct.