Boo Bow, Tillering Help! Pics

[RT]

Hi all,

I set out to built a two lams boo bow, Raw back and raw belly, both of the two lams has been pre tapered before Glue up. I do my pre tapering using hands tools and a caliper to help me access the gradual taper. I ran into problem when the consistancy when the right limb is not consistant with the left.
If the tapering is not too consistant thus during glue up when i put the limbs into 2 inches of reflex, the left limb bends a little more on the area "5" on the left limb as compared to the right limbs. This area "5" has created a steep reflex area.  Now from the next pic you will see Hinge form on 6 to 7,
And No matter how much I tried to remove wood from 5 and 4 the hinge at area "6 to 7" would just no go away. Yes, I am away I need to alos remove wood on the right limbs to get both limbs bending consistantly. I am very sure that the problem was cause by 2 things.
1) inconsistant tapering before glue up, thus causing in balance bending of the L and R limb. Has this happened to any one of u?

I am really stuck here and any word of advise on how to proceed here much appreciated.


 

 

[John Scifres]

I have not tried a bow like this.  If you can't remove material from the belly, you have to take it from the sides.

Are you exercising it a lot?  After each wood removal, bend it to draw weight at least 30 times.  This is a tough build.  But I have seen it work on other folks bows.  My guess is that the tapering you mention has to be about perfect.  I wish you luck.

[RT]

John,

yes, every time i remove wood, i will either floor tiller it (bend a few time) or pull it at least 12 to 15 time for it to register. what puzzles me as I have describe, no matter how much wood i remove from the area 5, i just cant get that area to bend.

[Mark Smeltzer]

RT,
That has happened to me a couple of times. The glue ups I do are highly reflexed and therefor in my opinion difficult to tiller.  That normally shows up when I move from the long string to a low brace ht. Much more stress on the outer limb.  On a bow that I thought was a total loss I used heat on the weak spot,tempering and bending in some reflex risking messing up the glue joint.  Another one I had to remove wood in the weak spot to prepare for a patch.
Also, removing wood from the right limb may relieve more stress from that hinge on the left limb than you think. I would get the right limb bending more befor I make any more moves on the left.
Just my  opinion.
Mark

[Mark Smeltzer]

TTT,
I'd like to hear someone elses take on it too.

Mark

[RT]

Hi mark,

Took you advise and slighly heated that area 6 and 5 *(where the steep reflex is) then i tried "hand bending" that area that refuse to budge. Succeded to get that "steep Reflex area" to bend eventually but then prior to this, i have stress the hinge area between 7 & 8 too much
thus causing the 7 & 8 to crystalised.
Well , like they always say Failure is a great teacher. I have failed thus time, but I have learn something valuable also. Till the next bow come along, cheers!

[horseapple]

RT, just curious to know if you staggered the nodes from belly to back?

JD

[RT]

evenly, and space outlike laying bricks, ensuring that NO two nodes are at the same place at the same time.

Horseapple , I have seen your built a long on the "How to Resorce section" man........u built some nice bows.......

Take a look at this site, this guys builts boo bow Tri or Quart lams with Raw Boo on back and belly
 http://www.bowsofwood.com/bows.aspx

I strongly believe that Raw boo not only give great tension, it is also can withstand a great deal of Compression (natures fibreglass)