@#$^& tillering problem...please help!!!

[canshooter]

This is the second bow in a row that this has happened to. This is a Hickory board bow with a bamboo backing. I was aiming for 50lbs@29 inches.

The bow is 72 inches long The Bamboo was reduced to 1/16 thickness. The tillering was coming along perfectly with no hinges  no flat spots and a nice D shape.

I am wondering If I am starting with a bow too wide (1.5 inches) perhaps the boo is overpowering the hickory, and to get down to my weight the hickory is becoming too thinned out.

Any answers?

 

By the way, I worked the bow a lot in between tillering, but never past 45 pounds.

[Pat B]

build a self bow!

[canshooter]

I will when I get some wood that is suitable. Till then its Home Depot Oak boards and Hickory board bows.

[bigcountry]

I bet you answered your question.  Its folding up the hickory.  But take my advsie with a grain of salt.  I am not too knowledgable.  

I would think 1.5" of boo is alot of tension compared to 1.5" of hickory

[Broken Arrows]

I thank you might be over working the bow between tillering try and slow down work the bow to 20 lb not 45lb check the tillering often. Also when you pick a board out for a bow try and cut the bow from a part of the board where the grain dose not run out to the side.

Dave

[John Scifres]

That should be plenty of belly wood and a decent design for a successful bow.  72" is overbuilt which isn't a bad thing right now.  There must have been a problem with the hickory or your tiller was too steep right there.  Do you think you might have rushed it?  I don't know what to suggest other than to try, try again.

[Pat B]

What glue did you use?  If Tite Bond, you can heat it up and the glue will release.

[canshooter]

I used titebond 3, are you suggesting that I re-use the bamboo on a new hickoy board?

[Pat B]

Yep! I've done it a couple of times.  All you need to do is get the glue to 150deg(F) and a bit of prying with set you free!

[Chisler]

I think Broken Arrows is right. The compression fractures (chrysallis??) are the result of too much bending before the wood is ready to bend.  My be the nature of the beast with the boards you are using, but go slow, and don't put too much weight on.  Are you using a scale?

[ChristopherO]

Steam will release TB3, too.
It could be the density of the hickory.  I've used pignut hickory that is very hard and dense.  I, also, used a stave out of a pignut tree that was much lighter.  The static recurve, sinew backed design is much too much for it and the belly is collapsing.  Same species have a lot of variance to them.

[canshooter]

If I get the Boo off would an Oak board bow be a decent option? I might be able to get a piece of Ash
as an alternative

[Jeremy]

Hickory is a much better option than ash or red oak.  red oak is pretty weak in compression.

[Pat B]

With boo backings you want to use a wood that is strong in compression for the belly. A bamboo backing will work on most bow woods if the bowyer is up for the task. If you are trying to learn bow building, find a design and suitable materials for your experience level. No since frustrating yourself by trying to over achieve.

[dutchwarbow]

this happened on a 130# boo backed massaranduba of mine. Perfect tiller, but somehow a huge crysal.

Nick

 

[Jesse Peltan]

Hickory isn't suitable for being backed by bamboo as far as I know. I saw a thread where someone made one but the tiller kept on changing and it eventually broke. I suggest something like ironwood, ipe, or osage. You can get "sample" ipe flooring boards for under a dollar from **** with free shipping. I suggest you buy two "samples" of ipe.

[Hud]

I think these are very good comments, but it is hard to know the cause without being there. If it were me, I'd rethink using kiln dried wood from any lumber yard. Boards are cut for their appearance which is not what we need for a bow. Knowing what you have learned, take the time to do some research. Before you do anything else, read a book like Hunting the Osage Bow by Dean Torges, or the DVD Hunting the Bamboo Backed Bow, also by D.Torges. I think you'll discover the answer to your questions. Glenn St. Charles talks about similar problems in his book Billets to Bows, page 68. Good luck.

[bubby]

build a few unbaced hickory first, go to a hardwood yard and pick through a unit and get a good board. should get several bows 1 3/4 wide from a board. I've built 60# plus bows with 29" draw unbacked. Just go to work on you're bow in a good fram of mind, somthing I learned from Pat B.

[Springbuck]

Frets come from bending wood too far.  That can either mean forcing wood to bend that is too thick, as mentioned, or a THIN spot that bends a lot while other areas are loafing.

Your boo it plenty thin.  

Do you know the trick about never bending the bow to more than target finished draw weight?  Put a scale on the string as you pull  the bow on the tillering tree.  If you want 50 lbs at 29", don't horse it back to 28 or 29 and 140 lbs!  Pull it to 50 at 2".  Then work it, balance it, and pull to 50# at 5", then to 50 at brace height and fix the tiller and stiffness as you go....

  Next time, narrow the bamboo back to 2/3 the width of the belly, then maybe toast the hickory at 1/2" thick or whatever before glue up.

[Roy Steele]

Build a stave bow.