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Main Boards => The Bowyer's Bench => Topic started by: wood carver 2 on May 16, 2015, 06:44:00 PM

Title: Bent bow
Post by: wood carver 2 on May 16, 2015, 06:44:00 PM

I know this has been asked before, but I don't remember the fix. The lower limb on a bamboo/maple/bamboo tri-lam I'm working on has begun to deflect off to one side. there is no twist, just a sideways deflection.
Which side do I work on to counter this?
Thanks!
Dave.

Title: Re: Bent bow
Post by: LittleBen on May 16, 2015, 07:42:00 PM

Did you glue up with titebond? If not what glue did you use?

Title: Re: Bent bow
Post by: wood carver 2 on May 16, 2015, 09:00:00 PM

I used TB3. Never had a problem with this glue.
Dave.

Title: Re: Bent bow
Post by: LittleBen on May 16, 2015, 09:52:00 PM

I only ask because I had some problems with TBIII introducing too much moisture into some multi-lam bows. In terms of strength it's awesome, I just was having trouble with stuff like you're talking abut using it.

It adds a bunch of moisture, and when the bow dries after glue up all sorts of weird stuff was happening.

As far as tilering, I think you're supposed to remove wood from the side away from the side the tip is bending towards. But then again I always check the drawing first ...

Title: Re: Bent bow
Post by: wood carver 2 on May 16, 2015, 10:15:00 PM

I was afraid that was what happened. The bow sat for a few days after being cut to profile and sanded, during which time the humidity rose quite a bit. I should have printed that drawing for reference. I wasn't sure which side to scrape.
Thanks Ben.
Dave.

Title: Re: Bent bow
Post by: Roy from Pa on May 17, 2015, 09:58:00 AM

 (http://i47.photobucket.com/albums/f165/ROY-CHRIS/Photobucket%20Desktop%20-%20ROYPAINTER-PC/String%20Tracking/limbalignment.jpg) (http://s47.photobucket.com/user/ROY-CHRIS/media/Photobucket%20Desktop%20-%20ROYPAINTER-PC/String%20Tracking/limbalignment.jpg.html)

Title: Re: Bent bow
Post by: fujimo on May 17, 2015, 11:16:00 AM

can always trust the ol' fella to save out butts!
i think that this should be put up top as a "sticky"- so its easy to find!

thanks roy- we all wait for this picture to be re posted everytime.
yer ok i guess!!

Title: Re: Bent bow
Post by: Roy from Pa on May 17, 2015, 11:38:00 AM

You girls need to take printer class 101..   :)

Title: Re: Bent bow
Post by: wood carver 2 on May 17, 2015, 05:57:00 PM

Thanks Roy. You're OK!    :bigsmyl:  
Dave.

Title: Re: Bent bow
Post by: mikkekeswick on May 19, 2015, 03:32:00 AM

It could also be natural 'grown in' tension in the wood relaxing.

Title: Re: Bent bow
Post by: wood carver 2 on May 19, 2015, 05:01:00 PM

I did some work on it yesterday and it's coming back to being straight now.
Thanks guys.
Dave.

Title: Re: Bent bow
Post by: Roy from Pa on May 20, 2015, 06:34:00 AM

Make sure the edges of the limbs are the same thickness. If one edge is thicker, that will cause the twist also.

Title: Re: Bent bow
Post by: wood carver 2 on May 20, 2015, 05:22:00 PM

I checked the thickness and sure enough, one side was a bit thicker than the other. I got it straight now. That bamboo can be tough to get even.
Dave.