Pre-forming all wood bow?

[Zradix]

Hey guys.
Couple weeks ago I was playing around with my bow jig.
Just moving around the posts, changing height of the posts etc.

Each time I made a change I'd clamp down a slat to see how it looked.

Anyway, once I was satisfied with the layout, I ended up leaving the slat clamped in the jig for the last couple weeks.

Went to look at it last night and the slat kept most of the curves when removed from the jig.

So it got me thinking...What if I kept a dry run/practice run of a tri lam clamped up for a couple weeks before I put glue to it.
...or for those with heat boxes you could even "heat treat" it for a bit.

Seems that if the wood was pre curved before gluing it would reduce stress on the glue, reduce "bounce back" after gluing, and might even prestress the wood into holding it's unbraced shape better which in theory could lead to reduced thickness in limbs ie..more speed and less vibes.

Any thoughts/experiences?

[bowhunter15]

I've wondered the same thing. Curious as to what others think.

[Pat B]

I think for sharp curves like recurves
pre-shaping the tips first is a good idea but for mild bends like in a R/D design I think you get better performance by forcing the shape at glue-up by clamping the lams to the form and letting the glue hold the shape once it is off the form. I get this thought from Perry reflexing, gluing in the reflex rather than pre-forming the shape before glue-up.

[Roy from Pa]

I doubt if you would gain much of anything. Without the glue holding the shape, it would straighten right out when tillered. But I do reflex my tips prior to glue up. I dunno know why, just some dumb thing I do.. Right Bowjunkie? LOL..  

[Mad Max]

"some dumb thing I (you) do"

you said it not me  

[Roy from Pa]

Shouldn't you be out in the swamp hunten gators or frogs or weeding your flower garden, boy?    

[KenH]

I pre-shape the wood lams for my Scythian style bows -- both glassed back & belly and all wood typs.  I hot water soak the lams for 4-6 hours at 105F or more, then clamp them into my open-top rubberband jig, starting in the center and working out to the tips.  Then I let them sit for a week to dry in place.  

When it's time to glue-up I'm not trying to force all that springiness into that extreme reflex/deflex/recurved shape at the same time.  Works A LOT better for me!  WIthout pre-shaping it literally takes 3 good men to hold things in place while clamping up the shape.

[monterey]

I pre bend the lam that runs up the ramps of my glass lam ASL builds.  That is the spot with the greatest potential for a poor glue joint and also a point of considerable stress.

[Mad Max]

I knowed I forgot sompin

[mikkekeswick]

No it's not a great idea. Pat is correct about perry reflex.

[Zradix]

Thanks for the comments Gents.    

[Roy from Pa]

You darn engineers... The wheel was already invented too, John..       LOL

[Zradix]

I know...I know...but so have been carbon fiber, fiberglass, and railguns...but here we are trying to glue a few pieces of wood together and expect it to bend over and over again....        
...also..just gluing a r/d bow up all at once isn't really quite what Perry reflex is all about..just sayin.

[Roy from Pa]

I don't worry about Perry reflex. I just worry about Roys reflex..  

[Mark R]

The pre-forming helps me to keep the glue up a little easier on steeper belly ramps for instance, performance wise I really don't know for sure, but anything that helps the glue up to be easier with less glue line foul ups will help performance, emo different materials will have different results I really am not interested in researching it but would gladly appreciate knowing the results from someone who has.