hinge repair?

[macbow]

I had finished a bamboo backed bullet wood longbow. it was 50# at 27 inches. Everything was good till i decided to measure it at 28 inches. It devoped a severe hinge, didn't crack, on one limb just behind the stiff portion of the limb tip. maybe 7 inches in from the tip.

I know it's shot for my draw weight. I'd like to reduce the weight and try to salvage it for a fiends daughter.

Should I just reduce the wood everywhere but the hinge or is there another solution, like a patch?
No picture available right now.
Ron

[Springbuck]

That is a problem spot on R/D bows.

  If the hinge was sudden, then something went, even if you can't see a crack.  So first look at it closely and flex/twist/backbend it slightly with your hand.  Look it over for cracks, laminatins that have separated, etc.  SOMETHING failed suddenly, so try to find out what.

  From here, I have seen a gazzillion fixes, both successful and not.

  If the bamboo lifted off the belly, I've seen people saw or cut aling the glue line and then glue in a thin tapered wedge.  You'd have to go past the hinge a bit and 7" is a bit long.

  It is possible to cut out a section on the belly like a shingle and glue in a small slat of bulletwood, then re-tiller.  Royal pain and often not successful.

  If the belly is sound, you could glue on a long, tip-stiffening overlay on the belly side. There is a guy on this site I've seen that does this, I wish I could pull ouyt a name for you.  His bows have won the Primitive Archer monthlybow contest before. These are pretty, but if the wood hinged for some underlying reason, it might not be strong enough.

  If the hinge has a cause you can see, like a crack or a lam separation, you can often work glue into it and cure it over the form again.

  Regardless, before you reduce the weight, find out WHY it folded up on you.

[dutchwarbow]

I had a similar thing happening on a boo-backed bulletwood 130# WARBOW. It got one huge crysal, but the tiller was spot-on before.

 

bulletwood is some weird stuff...

Nick

[John Scifres]

Hinges are almost always compression failures.  It stands to reason that if you add something to take the compression load, they can be band-aided.  I have added a patch before.  Get a drum sander like the kind you use on a drill press.  Trace and cut the radius of the drum out of the same material your belly is made of.  Then use the drum sander to remove the compression failure being careful to maintain the same radius that you cut from your patch.  Use a really good epoxy or Urac 185 as an adhesive.  Dean Torges taught me this.  He used to have an article called "Patching a Bow Limb" on his site to show it but I see it isn't working right now.  You can email him and maybe he can bring it back.   http://bowyersedge.com/

[Tom Leemans]

If I were to salvage it for me, I'd do as John said. My next option would be to cut the tips off and reduce the whole thing to a kids bow.

p.s. if you patch it like Dean's article shows with Urac, don't clamp the patch into place. The glue will suck it in just fine. Maybe a piece or two of tape to hold it still.

[macbow]

Thanks everyone, good info.
I acted before John posted. I did cut out about 5 inches of the bullet wood. I now have a patch glued in but the edges are ragged. I may use the drum sander to fix the edges.
I didn't know what a crysal was but that's what I have.
Ron