Primitive Archer
Main Discussion Area => Bows => Topic started by: brian_restivo on August 25, 2010, 02:13:54 am
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Anyone had a tip overlay come off?? I just had my second one come off while breaking in one for this season. Ya... I know I'm running late but times a premium. Last year I had one come off after a hundred shots or better. Luckally I found the damn thing, drilled about an 1/8th inch into each side of the glue joint and stuck a 1/4 chunk of nail in on the reglue. A little sanding and true oil good as new. That joint was hit with acetone 2 to 3 times each side and epoxied (ace hardware 5 min). Also well grooved with hacksaw blade. I thought I sovled the problem with a stronger epoxy. That and I studed all tips from then until now with that 1/4 inch peace of nail, just in case. Until this bow. I hit into the stud on the belly side of the tip. More than a little ticked off, I took a half inch of both sides and retipped it. This time with no stud, thinking the better epoxy was the answer. Nope.... Both failures where buffalo horn on osage. Both treated the same as far as multiple dousings of acetone. Both well surfaced with hacksaw blade. Both perfectly flat joints. If done the same thing with several other buffalo horn osage tips with no problem, but at this failure rate I'm afraid to carry any of them in the field. Im at a loss. Anyone have any Ideas. New glue??
I just checked. The new epoxy I was using is devcon 2 ton high strength rated to 2,500 lbs per inch. Surface on the tip that failed is 1/4 by about an inch. I took pictures on my phone but they where'nt very clear. The failure went though a bit of the horn. If the narrow tip is to fault, a wider tip would give a safety factor of any confidence. Again if any one has had isues like this, help a brother out. Next time I post I'll make sure its something positive. Maybe one on parabolic curves on limb layout
Brian
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I would skip the step where you rough it with a hacksaw blade and just sand it to take the shine off.
I have never degreased osage except when I first started. I think the hacksaw blade may be cutting down on the surface area you are matching up. Steve
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I'll have to try that but to tell you the truth... I'm about done with the overlays. If I can't trust them... Good thing I'm about done with a 100% primitive material bow for this season. It will have sinew/rawhide wraped knocks.
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Do you have full draw photo of that bow? Just curious if you have the bend spread too far into the tips.
gmc
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I'm with gmc - if the tip bends into the overlay you've got problems...
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Hmmmm... I've never had a tip overlay come off. Some pics would be good.
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nope... tips stiff for four inches. Positive thats not it, still have lines snapped and sprayed down the sides. I try to leave them right to the end. Lets me see where its taking the set. Its a little late for pictures of the bend, but this might be just the excuse I need to pick up a camera. At least I could get pics of both tips.
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I have found the 5 minute and two ton epoxies are not designed for bow work, very brittle and don't withstand shock well.
Try super glue gel. Most people that use horn for overlays use it as a glue. Acetone degreasing is unnecessary and too rough a surface is a minus, especially with super glue.
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I'll have to try that. It makes sense that its the epoxy. The one that came off last year I'm pretty sure it was the epoxy. The joint was good and tight until one day it turned white.
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on my heavy bows and recurves i have had super glue fail, devcon fail, but never titebond 3 just a light coat, clamp and a couple hours dry time and never had one come off. They call it wood glue for a reason. if nothing else give the tb3 a try. good luck to you- Ryan
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I'm with Ryan. Even my first bows that were less than refined, had rough looking glue jobs on the overlays have never failed using TB3. Gotta be it.
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I've had a tip overlay come off with the 5 min epoxy. (Happened at the Tenn. Classic last year when I bumped the tip end on my truck.) I Re-glued it with some super glue I borrowed from someone there. I shot the practice course with it and it didn't come back off. I haven't used the 5 min epoxy since. None of the ones I have glued on with super glue, tite bond, or Urac have failed but I definitely won't be using the 5 min epoxy again. I think it dries too brittle to handle the shock of the string return when shooting. :)
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Anyone tried "Kwick-It Blue" out of the 3Rivers catalog??
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Easiest solution would be to forget overlays on knocks. Unless maybe you're using a very soft wood, you don't really need them. I never put overlays on anything.
CP
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most all epoxies 5 min. or even long cure are very crystalline in nature and don't like to move at all. same with superglue but it seems to work. (don't know why)
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I have to use something for nocks. Tips are too narrow to notch. I could use a wrapped nock, but that would look a little out of place on this one. I'm probably gunna switch glues and go back to studding them. I'll have to keep it marked out better so I don't hit one again. Tho im not to fond of metal in my bows.
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I had a failure once with 5-min epox, came off in the shaping process.
Use superglue most of the time now, would give TB3 a chance, too, if it was wood, but not for horn overlays.
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I've put a bunch of overlays on with two-ton epoxy over the years and never had one come off. I never scored it with a hacksaw blade, though. I don't trust five-minute epoxy too far. The only overlay I ever had come off was purpleheart overlay on ipe glued with TBIII. The string broke on the bow at full draw, and it vibrated hard enough to crack and craze the finish all over the bow. About a month later, one of the overlays popped loose.
Cacatch, the main reason people use overlays isn't to protect the wood in most cases, it's to allow you to build skinny little tips that increase th bow's speed and performance.
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As in this case... I was trying to get some pics up with my new camera but the pics where to big and I'm done screw'n with it for today. I just ordered some kwick-it blue from 3rivers. They said thats what the use on there tomahawks so I've got my hopes up for it. I'll post how well it works in a week or 2.
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Yeah I know. What I was getting at though is that unless the wood is very soft and likely to be damaged by the string, you don't absolutely HAVE TO use overlays, there is a simple solution which is not to use them, (i.e. don't make the tips so pencil thin). The first few bows I made I made with the pencil-thin idea in mind too, and quickly found out that I flat out didn't like overlays and started to wonder why I was even doing them. Just because so many other guys did and it seemed like the thing to do? I decided to go my own way and quit the overlay pencil-thin obsession. If a guy likes overlays and all that, great. I just meant to point out that there is another option too.
CP
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You do have a point. Tho i've been going in the opposite direction. My tips keep getting narrower. I've only finished 7 or 8 bows (and maybe twice that in "learning experences"). I started using wood overlays on white wood with no problems and moved on to buffalo horn last year. I'm more drawn to the looks than anything else, that and trying different things.
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I have used titebond, super glue, two ton epoxy, and five minute epoxy. I have only ever had a tip come off with five minute epoxy I don't use it anymore.
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Easiest solution would be to forget overlays on knocks. Unless maybe you're using a very soft wood, you don't really need them. I never put overlays on anything.
CP
There's a lot of wisdom in these words.
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Yep... I think we have a consensus here. Don't use 5 min epoxy. Hopefully someone is saved from running out of cuss words.
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As Eric said, epoxies are too brittle and it's the shock that gets to them. Unfortunately I have also found that superglues are much the same, they seem to be acceptable when used on horn though. TB3 seems to work on everything.
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Brian, I have had the same problem in the past. I now use smooth on Epoxy and heat to dry. Since you have sealed the wood from previous glue attempts, it will be hard to re-glue. I would soak a horn tip in boiling water and super( glue as ryan) has said. Or make a tip with a split down the middle and splize on the tip with super glue. I have done the latter with success. Good Luck Denny
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Looks like Im going to be trying out a couple of glues and turning my head as I shoot.... Just in case. The guy I talked to at 3Rivers said Kwick-It is basically a super glue but for what ever reason takes the shock. 17 dollars for super glue, it better. I might rig up a test with scrap wood and some horn. Then drop increasing amounts of weights from it. That might give me a better idea of which glue to use.