glue ??

[PatM]

What's your guess...er diagnosis Pat B? 

[Jim Davis]

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.

Vinemaplebows, I must have been correcting my post while you were responding. Epoxy was only used to anchor the root in the sleeve.

[Pat B]

Pat, just as I guessed...the handle riser is on the same plain as the belly. I like to start with a 3/4" board so the riser sits above the belly plain.

[PEARL DRUMS]

Yup. Not the glues fault here.

[Pat B]

Very rarely is the glues fault.

[Jim Davis]

OK, then I want a miracle glue, because I want to use Osage laminations that are not good enough for the back of a bow. I have a lot of Osage that is curly, twisted, and so on that should be fine for bellies, or center laminations, but has no chance as the back.

So, now that we have sung the glib chorus about it not being the glue's fault, does anybody have  a constructive thought about how to make this kind of  lamination work.

Further, people do this with fiberglass/wood laminations all the time. So what glue works for them?

And, ["]the handle riser is on the same plain as the belly.[/"] Please note, the riser did not delaminate. The backing did.

[willie]

lots of shear at mid limb and the limb is bobbed abruptly on account of it being a take down.
might be some sort of stress concentration there.

I usually go to the boat building epoxies resins for challenging joints

[Pat B]

The belly has to be thick enough , even if it is multi-lam, so the riser doesn't sit on the same plain as the belly of the bow. See how Eric's  riser sits above the belly and the fades bring them together. So start out with a 3/4" belly, even if multi-lam, glue your riser to that then shape the side profile of the bow. A  3/4" thick center section will insure that the center of the bow, the handle area, will not bend as the bow is drawn. Your finished limb will be  5/8" to 1/2" at their thickest and maybe less so they will bend without causing the handle area to bend.
 I made a bow that kept popping the handle. I wanted to save the bow so I bought hemp cordage from WalMart, wrapped it tightly and saturated that with thinned 2ton epoxy. BINGO! it still holds. Now, most of my bows have short bulbous handles and the limbs bend right up to the handle so I wrapped the entire handle.
 With FG bows the FG run up the fades on the belly which locks the riser in place.  The fade area, whether FG or wood bow is where most of the stresses occur in a bow because of the leverage of the limbs. If you had improperly ground fades in a FG bow, that is the likely place it would fail. I know this for a fact.     

[PEARL DRUMS]

What's the glib chorus?

[Jim Davis]

Pearly I guess that was my frustrated sarcastic response, after it seemed like everyone was fixating on a "handle separation" when what I have is a backing separation. I've given up now

[lebhuntfish]

Jim do you have any pictures of your delaminated area?

Patrick

[Jim Davis]

see 1st page

[lebhuntfish]

Sorry Jim,  guess I missed that post. 
Im not really sure what would cause that seperation, especially since its inside a take down sleeve. 
Is the sleeve round? Or is it oval or D shape? I could see if there was some play inside the sleeve maybe.  But if im right you said you epoxied it in.  I could see a bit of a problem if the sleeve conection had a little play in it front to back that it could cause a problem.  But not sure it would cause a delam inside the take down sleeve.  Got me.

Patrick

[Jim Davis]

Last night I broke the glue joints in the whole root area to see what the bonds were like. The Titebond II just broke apart leaving both sides coated with cured glue. The wood did not break in that area. Farther out the limb, some of the wood split, leaving the glue line bonded.

[PatM]

That's interesting.  Did you glue the takedown sleeve on shortly after doing the lamination glue-up or leave it for a lengthy curing period first?   Maybe residual moisture from the TB never got out of there due to being encased in epoxy and metal and hampered the ultimate cure strength?