glue ??

[Jim Davis]

I've had Osage and hickory part company at fades and in glued up handles. I didn't think the handles were flexing, but maybe. Osage glued to Osage has also let go.

I have used both epoxy and Titebond II and both have failed at times. Is there a more dependable glue?

[Mo_coon-catcher]

I’ve always used tb3 with good results. Any time I’ve had it let go is if there is a bad glue line or I didn’t prep the surface properly. For prep I just sand the joint surfaces with 80 grit paper to give it a litttle texture.

Kyle

[Badger]

   Same as Kyle, I never degrease any wood or use grooves. If a bow is less than 3/4" think at the handle and longer than 64" drawing 50# the handle will have some flex, enough to pop the handle anyway. Maybe not right away but over time. This lams on the handle will usually stop this.

[Philipp A]

Did it pull fibre from the other layer when it failed? That would be the clue for you whether you had insufficient surface preparation or not. If it just failed clean then I think you would need to have a rougher surface before glueing.

[Pat B]

Will you post pics? A side view.
 TBII is stronger than TBIII. Did you prep as the glue suggested?

[PatM]

Grain orientation and different wood species create movement through different expansion and contraction rates that weaken a joint.

  Was the Osage to Osage  the same grain configuration?

 Many people mention Urac or Resorcinal as bomb proof for tricky glue-ups.

[Selfbowman]

I've heard the same about urac. I have also had the same problem Jim. Arvin

[kbear]

Preferring to keep everything as organic as possible, I use gelatin glue. 6:1 with straight white vinegar for sizing, and a thicker 3:1 for the glue up. This stuff is strong. Probably not as strong as Titebond et al, and not as waterproof either. I have had handles "pop", ripping chunks of wood from either side, so as extra insurance, I now wrap the section of the handle to be covered with leather, with a high quality linen twine, and gelatin glue that too. Very strong. Haven't had one pop yet with this method, mind, I am fairly new at this obsession.

I think that handle and fade design has a lot to do with it too.......

[lebhuntfish]

   Same as Kyle, I never degrease any wood or use grooves. If a bow is less than 3/4" think at the handle and longer than 64" drawing 50# the handle will have some flex, enough to pop the handle anyway. Maybe not right away but over time. This lams on the handle will usually stop this.

X2
A good clean glue line is a must for any glue up.

Patrick

[Eric Krewson]

I never had a handle pop after I started using urac and lengthening and feathering the fades, no problems with unibond except having it set up in the can. The last I did was with smooth on, no problems so far. That is at least at least 140 glued on handles with no pop offs.

I always matched the mating surfaces where I couldn't see light between the two pieces and roughed both pieces up with a toothing plane.

If my stave is thin I put a couple of pieces of 1/8" thick pieces down first before I put on the bulk of my handle material.

Like this;

[Dances with squirrels]

What kind of epoxy did you use? I had one handle piece come loose almost 20 years ago, and not one since. It was purpleheart on yew, and their differences may have been the cause. Or it could have been a starved glue joint because I did things differently back then.

Anyhow... since then.... I use Smooth On EA-40, mate the pieces together as perfectly as I can, then scrape them with a toothing plane blade that is VERY slightly convex shaped. Since many of these glue ups are with curved/deflexed pieces, I do this without the planer body, while holding just the blade by hand, like a scraper, creating grooves parallel with the full length of both pieces to be glued, until they are the full depth of the teeth. Then glue with Smooth On, clamp, and set a shop light nearby for warmth.

If mixing epoxy, be certain it's adequately mixed. Spend an extra minute.

I have never had anything come loose or separate even the tiniest amount when prepped this way, including pieces that flex... sometimes I purposely flex the wood into the added on dip/handle piece. I leave no pedestal of extra thickness, and use no power lams. I've done this on short, stressed designs, and bows up to 70 lbs. It's worked every time... or maybe I've just been really, really lucky 

[PatM]

I wonder if design differences alter the stresses felt on a glued on riser.  Both Jim and Arvin prefer pyramids and Jeff and Eric the narrower radiused  type.   Perhaps the flatter pyramid feels the poisson effect more at the wider fades and starts degrading there.

[Pat B]

If we could see a side view of the riser area we could diagnose the problem. Guessing is fun but not very productive usually.

[Jim Davis]

Here's a pix. Back layer is hickory. Belly and handle riser are Osage. This was a limb in one of my sleeve take-downs. I used Titebond II on the whole limb. The stub was epoxied into the sleeve with no room to flex. The fade area held, but the root apparently failed in shear?

I have other bows glued the same way that have not let go--yet. The other limb of this bow did not fail. I treated both limbs the same way. Glued up in slight reflex, which they lost.

Strung image is a different bow,  but design is the same.

[vinemaplebows]

NEVER use 5- minute epoxy on limbs, way too brittle. If you want to use a store brand, I strongly suggest Devcon 30 minute set epoxy. As mentioned above mix, and mix some more. I personally only use Devcon on splices, never had a failure there, do not over clamp.