Takedown tenon keeps lossening.

[Salsify]

Hey all,
seeking some advice on a little problem I’ve been having.

I recently completed an osage bow with a fiberglass takedown handle, and I cant get the fit to stay tight for more then a month at a time!
 I was able to temporarily fix it by putting on a thick layer of polyurethane, letting it just set up(but still tacky) then shoved it firmly into the socket and removed it. Worked great, until a few weeks later when I noticed it had loosened again.

I repeated the procedure again, and here I am a month later, once again I’m looking at a limb that will simply fall right out of the socket if turned upside down unstrung. Anyone have a permanent fix for this?

That is, a fix that preferably doesn't involve tearing out and redoing the handle of an already complete and shooting bow =x
I had this problem once before, and I tried spreading a little resin mixed with some micro fiber filler dust(for strength I hoped) on the tenon with a release agent. Of coarse it somehow bonded the two pieces together and I had to redo the handle on that one. I could try again, but I’m still worried all I will have done is added a very brittle layer of resin that will break off at some point.

Thoughts?

[Pat B]

Is this a commercially available fiberglass takedown system or one you made up yourself? If a commercial I would contact who you got it from for advise unless someone here has advice. Will you post pics of the handle together and apart so we can get a better picture of the problem?

[stuckinthemud]

Is the problem that the sleeve is stretching? Not something I have experience with, but if so maybe try wrapping  with a non-stretch material like linen thread and bonding that on as a re-enforcement?

[PatM]

Are you sure your billets were dry?

[Salsify]

Pat B: Nope, this is a hand made, big Jim style fiberglass deal.

Pat M: Yes, they sat for two years in billet form at a humidity and temperature range that would have put them at an optimal MC. I have been moving about with the bow the last few months, from a humid environment to desert. But at this point the tenon has far more sealant then I’ve ever put on a bow, so I would be surprised if it was adjusting to a lower MC and shrinking that much that quickly, as it would be a 2-3% change at most anyway.

[PatM]

I think that's the answer though.

[bownarra]

Your billets were still holding on to moisture. 100%
The glass cannot move, the wood is the only thing that can move.
It doesn't matter how long wood has sat (especially in stave form) when you reduce it and expose it to lower r.h it WILL shrink....
The only way to sort this out is to remove the sleeve and make another....it won't move this time! I would even gently heat the exposed wood before wrapping again. It won't come loose again! You want the wood for a socket to be at 6% - no more.

[Salsify]

To clarify, it was exposed to lower RH AFTER it was already completed, like months after the finished bow had been sealed. But if memory serves the mc was coming in around 8-9%, so if 6% is the ideal… could it really have lost moisture that noticeably and quickly when already sealed?

Is the suggestion of redoing the handle too make a tighter fit to the wood tenon? Couldn't I just add a void filler of some sort? I’ve had ti Strip and redo a handle once before, it’s an awful lot of extra work it seems..

[Salsify]

Here are some pics of the handle if that helps, thought I uploaded then last night but they didn't go thru

[Hamish]

 Does the looseness effect the shooting of the bow?

[bownarra]

Well unless you wrapped it loosely then something moved....it cannot be the glass wrap so the wood had to have shrunk.
I used to make custom glass bows too with fancy risers - lots of different woods laminated togther....you might be surprised how much wood can move....and how long it can sit...and still move.
your wood shrunk - trust me! Finish or not makes no difference really. No finish stops moisture transfer - they only slow the rate of transfer.
The aim of sizing is to prodcue a smooth thin layer of dried glue so that you cannot starve the joint. If your parts fit well you don't really need clamps on splices. Just hold until it is gelled. The glue pulls the parts together as it dries.

[Kidder]

Have you considered sanding the tenon down a little and adding a thin fiberglass wrap and then sanding that to fit?