Laminating

[Barrage]

Ok, I need some opinions.  I've glued reflex into a couple different bows using yellow wood glue (titebond II or equivalent) and to clamp I used rubber bike tubes.  The issue I've had is that as I progress with tillering, there is a bit of a propeller twist in both limbs, in opposite directions.  The only thing I can think of is that when wrapping with the bike tubes, a small amount of twist is induced and glued in (even though there is nothing obvious to the eye at the time).  Then as the bow is drawn the forces held in the glue line become more pronounced and thus the propeller.  At least this is what I think is happening.

So, any ideas?  What method are you guys using to glue up your laminated bows so I can avoid this? 

Thanks

[james parker]

if you are going to continue to use rubber tubes,try wrapping in both directions in criss cross pattern,this way you should not have twist to one side, if you still have twist, check your form with a square and a straight edge ruller,if you still have a twist .lock the bow down in a vise ,heat the limbs with a heat gun and tourqe the limbs the othe way,go past center a little and tie off the limbs,let set over night,this should correct the twist,i have used this method many times,and of late,the other day i took out over 2 inches of twist out of a limb- its dead on now ...good luck ...ps..make sure you heat the limbs suffeciently enough to hold some heat while you correct the limbs............robustus

[Kent D.]

I use that technique as well.  I noticed that happen with my very first glue up I ever did.  To solve the problem, I wrap down the limb (starting at midline of the handle area) one direction, then when I get to the tip of the limb, I keep on wraping and come back down the limb and end where I started.  This will even out the torque.  Ive never had a problem since.

[sailordad]

is your limb thicknes from side to side on one limb the same thicknesses?
if not this will cause twist when tilering,make sure you have even thickness side to side

[Barrage]

Sailordad, yeah, the limbthickness is even across.  I checked, then rechecked, then rechecked again.  I'm 99% sure it's glue up induced.

Robustus and Burnie, thanks for the criss cross idea.  I'll have to try that on the next one.

Robustus, any risk of getting the limb too hot and delaminating (not that I have much to lose at this point )?

[james parker]

heat the limb,but not too hot that you cant hold it...heat it all the way around including the edges,,,let us know how you fair with it...robustus