Estimate the Weight for this Layup...

[Dick in Seattle]

Well, I'm stuck in the snow and cold with cabin fever, ready to build my next bow, and nothing I can do for the moment but worry over just how to lay it up.

My last bow was .050 glass, .110 yew, .120 yew, .110 yew and .050 glass.  All three yew lams were .002 taper. Riser was 11" total to ends of fades and bow ended up 64" and 38# @ 25" (45@28) but very stiff at the end of the draw.  There is no power "curve"... draw weight increases in a straight line progression from beginning of draw to anchor.

I've got a lot of stuff changing at once on this next one... I want it to come out lighter, but with shorter limbs and a longer riser, (looking for some speed increase)and with a tip wedge where the previous one didn't have one. It’s clearly going to be a kind of "by guess and by God" proposition... but once this one comes out, I'll be better able to judge the next, and so on.

What I’m looking at is .040 or .045 glass and two wood lams  (I could conceivably use .040 on the back and .045 on the belly)... One parallel osage lam of .120 and one tapered osage .090, with a tip wedge. I plan to extend the riser to 14" and I''m shooting for a 62" bow. These ideas have been changing constantly, but I have to just buckle down and do something as soon as I can get back into the shop.

What I'm looking at would be either .010 or .020 less glass (depending on which set of glass I use) and .130 less wood.  That obviously represents less draw weight in the bow.  However, the shorter planned length, the longer riser and the tip wedge represent an increase in draw weight.   Yikes!  

I plan to layup and nock initially for about 66", and if it comes out light shorten to taste, hopefully down to the desired 62"... If it comes out heavy, I'm in trouble. I can come out as light as 28# and be a happy camper, or as heavy as 35# if the draw is better than I got the last time.

I know it's a crapshoot the first time, but what I'm hoping is that someone with experience could make a guess at what weight the suggested layup will produce with the longer riser and shorter limb?  Limbs will be between 1 1/2 and 1 3/4 wide flatbow, like the pic...  

 

[TNstickn]

I sure could'nt guess, but it's fun tryin to figure it out!! Best of luck.   :D

[Bob Sarrels]

Dont know what your final weight might be but I bet its gonna stack with that many tapers.  Bob

[Dick in Seattle]

Thanks, Bob.... that's the kind of input I need.   Probably why my last one doesn't ease up for me.  Still mulling this.... I was at Rockler's today looking at some maple... should have bought it... may go back in the morning.  I could make a couple of maple parallels...