Burlap Backing?

[Arrowind]

I'm a new Bowyer.  I started in November and I think I've found a new hobby....er ah obsession.   

I've used burlap to back two bows using Titebond II on one (Red Oak Board Bow) and Titebond III on the other (Hickory Board Bow).  In both cases I've notice that when the glue dries it seems to induce a bit of set.  If I understand correctly the clue shrinks when it dries so I can see how this could happen but I have to wonder if I'm doing something wrong.

Has anyone else experienced this?  Does anyone have suggestions on how I could avoid this?  I think possible answers could be "use less glue", "use different glue", "water the glue down???", "use a different backing" but I'm just not sure.  I like the nature of burlap and the texture too but I'm not interested in adding set when I'm trying to avoid it.  It seems like it takes a lot of glue to avoid stray fibers sticking out all over the place.....

I would appreciate any suggestions.

Thanks!

[George Tsoukalas]

I like burlap too. I back right after long string tillering and really haven't noticed  any additional set in burlap backed bows. Jawge

[Arrowind]

I've been backing prior to tillering...I'm not sure if that changes things or not. If so please let me know.  What have you used for glue?  I'm sure it's hard to describe but how much?  I've been caking it on pretty good then spreading it smooth.  I put some on the bow, lay the burlap out spread it smooth then put some on top of the burlap and spread it smooth.  Let dry over night.

[half eye]

Arrowind,
       I have backed some bows....both with hemp, burlap, and wood. I use TB II for all of it. What you may be seeing is when you stretch the wet burlab it drys "under tension" then as you remove wood to tiller, the tension is pulling the weaker piece of wood into either reflex or deflex. Where as the wood was too strong in the beginning for the burlap to affect it so it is not noticeable at the beginning.
       Dont know if that's what your experiencing or not, but it is one explanation....JMO
rich

[Arrowind]

Thanks.  Actually what is happening is that both limbs are perfectly straight before I apply the burlap.  When it dries I am getting about a half inch of set.  This is all prior to tiller.  My last one, a Hickory board bow, (yes I backed Hickory. It had two massive splinters on the back that I tried to sand out but they were so deep I started to worry so i decided to back it.) actually had a little set before I backed it because like an idiot I pulled to to 70lbs way too soon.  I was just starting long string tiller... anyway the burlap seemed to increase set.... Maybe I had already weakened it?  At the time of gluing the burlap on I even set each limb up on a block of wood so the bow was off the bench about an inch or two then clamped the handle down to try and induce a bit of reflex as it dried but to no avail. 

I have a lot to learn.   

I may do a test and take before and after pics just to see if I can reproduce it...... 

[sailordad]

nevr used burlap
but i have made many hick board bows backed with camo cotton fabric with tbIII
never noticed it inducing set
i am sure yur letting the glue dry
however are you letting the wood dry also after you glue it ?
the glue may be ading some moisture into the wood
then working the wood to soon after could be causing the set
just a thought,but i am no expert 

[George Tsoukalas]

I used Titebond 2 on burlap.

[Arrowind]

nevr used burlap
but i have made many hick board bows backed with camo cotton fabric with tbIII
never noticed it inducing set
i am sure yur letting the glue dry
however are you letting the wood dry also after you glue it ?
the glue may be ading some moisture into the wood
then working the wood to soon after could be causing the set
just a thought,but i am no expert 

I am using kiln dried lumber...and I live in Arizona.  it's pretty dry here to begin with.   Maybe i should soak the wood a few days before I start?

[sailordad]

yes even kiln dried wood an absorb moisture
even moisture from glues
that is enough moisture to cause set to set in 
wood is hygroscopic
being kild dried does not prevent that
anytime you apply anything wet to wood,the wood is going to suck in some moisture and will need to
dry some before being worked
well atleast thats my belief and what i do when i apply a backing
i never assume that once the glue is dried,that its dried enough

[Arrowind]

You guys are awesome.  Thanks for all the responses.  And so quick.  I really appreciate it.  I am starting to think that maybe I'm imagining all of this....It seems like such an odd thing.

[Arrowind]

yes even kiln dried wood an absorb moisture
even moisture from glues
that is enough moisture to cause set to set in 
wood is hygroscopic
being kild dried does not prevent that
anytime you apply anything wet to wood,the wood is going to suck in some moisture and will need to
dry some before being worked
well atleast thats my belief and what i do when i apply a backing
i never assume that once the glue is dried,that its dried enough

interesting.  Yeah it's so dry here that makes a lot of sense.  It's also one reason i wanted to try Hickory because I read that it is was good for dry climates.  It must also be like a sponge.  Yeah I was'nt thinking that it was too dry for that to happen but the opposite.  It's so dry that any moisture is readily soaked up. Just as youve suggested....

Or maybe i should let it sit for a week before working it.....
Thanks for your help on this.