Questions on glued in reflex

[GentlemanArcher]

Hi All,

I'm new to making bows.  As an experiment, I thought I'd try gluing in some reflex to a wood bow.  Since I'm sticking with red oak till I feel brave enough to pay more for wood, I used 1/4" thick, 1.5 inch wide pieces from Lowe's.  For the backing, I used poplar in the same dimensions.  Not the best choices of wood, I know, but cheap and available.  Anywho...

72 inches long, 1/2 inch thick riser glued on on belly and 1/4 piece of red oak glued on the front.  I clamped the bow, belly down, and used 3" tall blocks to hold the reflex while the glue set.

The glue set up well and the bow holds its shape nicely (at least eyeballing it).  I used a bandsaw and belt sander to taper the width of the limbs from the rise, down to 1/2 at the tips.  the floor tillering felt ok at this point.

I exercised the bow some and used a long string on my tiller tree.  I'm getting ~20# at 14 inches (with the long string).

Finally we get to the question.  

One limb felt heavier at this point.  Using my spring scale, I pulled each tip down 3" and measured several times. One limb is 9 pounds and the other 10.  Since the thickness of the limbs is the same, I measured the width of the limbs at several points.  The weaker limb is the wider limb....

ok, so now, I'm at the question for real....
Shouldn't the wider limb be the stiffer limb????

Question two:
What can I do to get the bow to the draw length, while keeping the final draw weight at around 30#? (Ultimately I'd like to make a pretty and reasonably fast for it's draw weight wood bow for my wife that's around 25# at 26")

I've read that if I remove would from the belly, I'll increase the reflex (which I understand)...but increasing the reflex will also make it harder to reach the draw length won't it?

I suppose I could narrow both limbs.  And round the corners of the back more.

Maybe all this is a result of the wood choices.  I do have some maple, walnut and a I just got 7 bf of hickory.

Or do I go with Plan SO (SO = Start Over)?  And use 1/8 or 1/16 thick backing.  

Any constructive feedback is appreciated.  And I'll get some pics up when I can.

Thanks
Philip

[Stiks-n-Strings]

I'm kind of looking forward to hearing how the poplar backing holds up. I don't think I would be suprised if she blows.

 You just need to scrape the belly and get it to a low brace on a short string then start tillering it out to full draw. You just have to keep removing wood until get good tiller and reach full draw and desired weight.

 Tiller it in a few pounds heavy because it will drop some during shoot in and final sanding.

 If you got all that hickory you could build a hickory backed hickory. Alot of better choices for backing than poplar and probably just as reasonably priced.

[Art B]

Philip, I think you just discovered what uneven working properties means. Heavier limb is from the trunk end of the tree. That's why when I build a stave bow I "build it as it stands in the tree". Lower limb will show a bit narrower than the uppper but will still be the stronger limb. Bows from sister billets, with closely matched working properties, will show limbs of equal dimensions.

Best way to even things up is to get your permanent string on early in the process and even tiller up from there. Once you have a even tiller, it's a simple matter of reducing limb weight back to your draw length.

[GentlemanArcher]

Yep, a hickory backed hickory bow is already on the project list.  As is a hickory backed walnut bow.  

@Stiks-n-Strings ... I won't be surprised either!  this really was an experiment with the lumber I had laying around.  I'll tiller the heck out of it and see what happens.  Maybe I can get the draw weight low enough that it doesn't break  

I'll work on getting a few 1.5 inch wide pieces of hickory cut.  I'll try to make some thin pieces for backing or even tampers as well.  My shop tools aren't the best or that plentiful.  I'll have to try to use my drill press as a drum sander.

[GentlemanArcher]

the poplar backing cracked when I got to 26: draw with the low brace height.  A piece about 1" long and about 1/4 inch wide lifted about mid limb.  

Since I was experimenting anyway, I glued it back down and then backed the limbs with fabric fiberglass using 2-ton expoxy.  The glass fabric was left over from an old project, so I thought, why not.  Pain to deal with, but now I can draw to 26 inches again and no new cracks.  I've been wearing my bicycle helmet as I tiller and draw it     Good thing I work in a basement shop!

I figure I'll look pretty cool at the range in my "limb protection head gear"  haha

I'll get some pics up soon.
GA

[psychmonky]

How much glass did you use, and did it add much draw weight? I was thinking about backing a board bow with it.

Scott

[monterey]

Did you find one single piece of oak at 1.5 X 72 or did you put two pieces of 1.5 X 36 together with one piece being each limb?

If you used two differnt red oak laths, you have a good chance of having very different characteristics in each limb.  I did this when making a wide pyramid bow with the intent of making a 66" bow.  The two pieces were so out of whack it made no sense to continue.  Instead I went with a 52" bow using a single lath cut in half at the center and with a four inch piece used to fill the gap to make a 52" TTT bow.  The riser wood was glued to the belly side and then a piece of back overlay to help hold it down.  This made an excellent 51" NTN kid bow.  The width was about 2.25 inch.  No wood back, since a kids bow it was backed with 20# bond paper and tb3.

Sorry to go on, but thought my experience with that type of wood might be useful.

[GentlemanArcher]

@psychmonky
I used the lightest fiberglass fabric the hobby store had.  Don't remember the weight.  It's super light.  I put strips of masking tape on the fabric and cut down the tape.  That gave the material some form and keep the fibers from fraying as much. It cost you some fabric of course, but I figured the "waste" was worth fewer fibers floating around and for making it easier to handle.  I used only one layer.  The draw weight didn't change.

The only change I did notice was as I first pulled the bow to my draw length, there was lots of cracking sounds.  Turns out it was the epoxy at the  edges of the bow.  After filing the extra off and sanding down the corners, the crackling noises went away.  

Of course, I'm still wearing my helmet when I draw this thing  

@ Monterey....that makes perfect sense!  I did use two separate pieces.  That could easily explain the difference.  The next experiment is going to be hickory backed hickory, or maybe hickory backed walnut.  I'll get those pieces all from the same 72 inch long boards.

Kia Kaha