Need help! please! limb thickness and taper for recurve

[Rob Brown]

Hi there I am building my first fibre glass recurve bow and need help. I am making the limbs with materials in order fibreglass, bamboo, purple heart, bamboo and then fibreglass again. I am first going to glue the wood lams to the risor using the form and then tiller it and once I am satisfied then glue the glass on using the form again. My problem is I don't know what thickness and taper to make the limbs before applying the fibre glass and my wood is all self sourced, cut and thicknessed which is less predictable than precut wood slats from a bow shop. could somebody please recomend a thickness for the limbs. I am wanting it come out 45#-50#. Any help would be much appreciated

[Robertfishes]

Rob, I recently started building some simple but good shooting recurves using a DVD instructional video and a blueprint purchased from  www.binghamprojects.com    Their web site and  instructions include a thickness chart for weight estimation.   I slightly modified their design by adding a little more hook (1/8") and tapering from the fades (1 3/4")to tip ( 5/8"). this is a picture of one of the 58" recurves I built off of their plans and instructions.  

[Robertfishes]

Rob, I used .040 glass, .032 veneers and .110 red elm core with .002/in taper. for a total stack of .254 and the bow came out at 51 lbs @ 28 "

[Robertfishes]

Rob, here's another. I made a lower wrist grip on this one.  I used a .103 red elm core with .002/in taper, .041 glass and .030 veneers for a total stack of .245, the bow pulls arround 44 lbs @ 28"  

[Rob Brown]

Hey there Robert thanks so much for the input I had a look at the chart and I think I'll try make my limbs 58"length and 6.4mm width which works out to about 0.252". I am using a 24hour glue(resorcinol) which cures without heat and am using bicycle tubes to apply pressure instead of clamps do you think this could effect the finished bow?

By the way those bows look realy good!  

Oh an I was wondering what would be beter because I can use either bamboo or hickory?

[Robertfishes]

I don t think  resorcinol will work well in fiberglass to wood applications. Something like Smooth on or Versamid would be a good choice. When you say bamboo are you talking about laminated actionboo? Maybe the hickory would be a good choice, I am wanting to try some stained hickory as the taper and parallel in a future build. Lots of guys use the rubber intertubes with great success, I use the fire hose method with 65 psi of air pressure. Use the search function and you can find a lot of good information.

[Rob Brown]

Ah ok yeah I fogot about the glass to wood for that I have a south african epoxy simular to smooth-on it works quite well. The only prob with the hickory is that it was quite a wavey piece and isnt as uniform as the bamboo. The bamboo i actualy got from flooring and is suprisingly quite decent stuff. I was contemplating making a form that uses a hose but i dont get that much opportunity to work on bows. But again thanx a lot for the info I think what i must do is just build the thing and stop changing ideas. Practice makes perfect haha. Thanks Robert.