Glass-backed board bow

[KenH]

OK, just for fun...  Let's say I build a board bow from Osage or Red Elm or whatever,and then back it with a regular composite bow fiberglass strip.  

Will that cause any problems?  Will the glass act like sinew and increase the draw weight?

What if you put glass only on the belly?  What would that do to draw weight?

[Pat B]

Why?  There are other better options.
 A couple of years ago a few bowyers tried building bows with just glass backs and the results were less than optimal. Bamboo, hickory or hard maple would give you better results.
 Adding a glass back will increase draw weight but so will the other backings I mentioned and with better results.

[Troy D. Breeding]

Built one like this humpteen years ago and it was a disaster. Shot OK for what it was, but would jolt your teeth out with every shot.

[Wolftrail]

I just finished a takedown bow. In the final stages of applying finsh and tweaking a little. At any rate I built 2 sets of limbs for the riser. 1 set is wood other is same but I backed the limbs with woven glass (just because). They seem perfectly fine so far. 2 layers of glass about total thickness of .050 - .060 thou.
 Both sets of limbs have been shot in about 70 times, the glass backed limbs have taken double the set of the all wood about 1/2".  The all wood limbs are smoother drawing but a little less weight. The glass ones are 65" NTN the other set is 67" NTN. Now there are other variations in the limbs, the glass ones have more reflex near the tips and the fades are a little thicker and the wedge is 8" others are 6".

 They are built entirely from sugar Maple. The wood limbs are backed with one layer of linen.
I like to experiment with backings. So far I tried Linen, Nylon, Denim, Silk, Fiber glass and brown paper bag.
My experience has been good so far with nylon, linen and glass. The others I will never use again.

[mikkekeswick]

Air makes a good backing for osage.  

The problem is that a good wooden bow has balanced tension and compression properties.
Strong in tension/weak in compression = chrysals. Vice versa stronger in compression/weak in tension = bang!
Basically the belly will be forced to compress more than it should by the very resistant to stretch glass resulting in more set.

[JamesV]

I have built a few wood bows backed with glass and everyone failed after some time, the wood was overpowered by the glass. These were in the 45-50# range.

James

[Wolftrail]

Good to know thanks for the heads up.