glue/tip overlay problem

[Newindian]

Have a bow that had the tips broken off three times, decided to replace them entirely with a more exotic lamination, bow some how managed to crush the middle wood lamination. I tried to regule it back on three or four times each time the glue line would fail sooner , leaving the bottom bone layer behind, the last time I just pushed it off with my thumb (I think the surfaces became impregnated with the glue, I've been using tb3). Finally replaced the entire thing with a single piece of purple heart, shot it 50 times held up well, started to work on finishing up the bow, string it and four seconds later it fails at the glue line. Uuuuuuuuuhhhhhhhhhh. This bow is heavier than what I normally make ,60#, but I wouldn't think that would be much of a problem same glue is working fine on a 50#, I'm thinking I need to try a different glue though. Any thoughts appreciated.

[Danzn Bar]

I have had good luck with CA or Loctite super glue.  Some woods are very oily and need wiping with acetone and a thin sizing coat of glue before clamping together.
DBar

[4dog]

Have you tried staples? 

[Pat B]

I doubt it is a glue problem. Probably impropper prep or other human error. Will you take pics so we can see how the overlay was attached?

[Newindian]

Once the end of the bow have been rounded I have a hard time using clamps,what I'll do is when the surfaces match I'll go over them with the rough side of my rasp (Shinto) cover them In glue, press them as hard as I can to the other surface and let the suction hold it. I've used this method a dozen times with no problems before. First pic is of the failed tip, which I've already prepped for the next try, the bow still needs to be cleaned up some, second pic shows the surfaces pressed together, third is the opposite tip.

[HickoryHick]

Don't rasp the tip, the glue won't adhere as well. (TBB Vol1 page 195) the glue needs to soak into the wood, roughing it up gives you less contact, therefore a weaker joint. Sand the surfaces smooth, make sure all the dust is gone, degrease, size the surfaces with a little glue first, then add more and clamp. You can "starve" the glue joint if you don't let a layer soak in first.

HH

[Newindian]

The surface left behind by the rasp is equivalent to what sandpaper leaves behind, forgot to mention that I take a file to it after the rasp

[soy]

Back nocks make me nervous out of the gate especially short narrow ones....maybe a bit more length for more gluing  surface and d grease with  denatured alcohol I am too have had problems with gluing Horn and bone wood just seems to adhere better

[mikekeswick]

Use the best quality slow setting superglue you can find.
Never roughen up surfaces when using TB -trust me not even a little bit. For a good bond the gluing surfaces must be flawless. DO NOT ROUGHEN.
TB is a water based glue that soaks into the surface, use it once - fine. Try to reuse it on the same piece and it won't work because the glue has already soaked into the gaps (microscopic gaps).
I've never had to worry about degreasing with correctly mating surfaces and good quality CA glue. I've done plenty of tests with it and even gluing ebony and lignum vitae the bond was very strong with the wood failing first (no degreasing).
Forget the TB it takes a day to dry! CA give it one hour and you are good to go.

[Del the cat]

I had it hapen once, I think moisture got into the endgrain of the wood after a wet days shooting.
Here's my fix.
http://bowyersdiary.blogspot.co.uk/2012/07/equipment-malfunctions.html
I made a virtue of necessity.
I do notice that the overlay is V thin at the groove, I wonder if it is flexing at that point a tad and loosening it?
Del

[Newindian]

I do notice that the overlay is V thin at the groove, I wonder if it is flexing at that point a tad and loosening it?
Del

I thought of the same same thing but the previous overlay would leave the bottom lamination, this one is a little longer than that one though, I'm going to give loctite superglue a try.

[PEARL DRUMS]

Use a GOOD ca glue and never look back.

[Thesquirrelslinger]

epoxy? Its more tolerant of gaps than any other glue to my knowledge.

[PEARL DRUMS]

The bonus with good ca glue is it will adhere to anything. Some epoxy glues and such wont grab unto horn or oily woods like ca glue does. And, as Mike noted it dries in 10 minutes and you can continue on.

[osage outlaw]

I use several rubber bands to hold the overlay on when I glue it.