Primitive Archer
Main Discussion Area => Bows => Topic started by: Apex Predator on May 19, 2008, 09:25:01 pm
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I have been having trouble with my glue lines on tips and handles. The fit is always good or I won't glue it up. I have had this problem with TB III on handles and epoxy on tip overlays. When the bow is finished and shot I notice the seams seem to expand or something. Nothing has let loose yet, but it looks bad. I started using CA gel for all my tips and have had no more troubles. All my grips start to do this though. Even with power lams, or good built up islands under my handles. My limbs are fine. These joints are all but invisible until have finished the bow and shoot them quite a bit. Maybe I should shoot them more before final sanding, and these will be sanded out? Check out this photo and tell me what you think my problem could be.
(http://i121.photobucket.com/albums/o203/Apex-Predator/Apex%20bows/Handleglueline.jpg)
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Looks to me like the limbs are bending into the fades.
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It would be really nice to see how thick the handle is from the side. I actually wonder if it is slipping or just changing colors. What does the fade look like on the other limb. It might be that your finish is soaking into the water based TB and causing it to expand right on the edge. Justin
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That usually means the fades are bending slightly - it doesn't take much.
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This is only happening in my ipe-ipe joints, and in areas that aren't bending. Only appears after finishing and shooting. You can feel the joint. All my other joints are fine, including ipe-boo, ipe-red oak, ipe-mahogany, and ipe-hickory.
(http://i121.photobucket.com/albums/o203/Apex-Predator/Apex%20bows/Handleglueline-2.jpg)
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Are you using TBIII for the entire glue up or just the handle?
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TB III for all except overlays, which I have started using CA Gel. I have had tip overlays do the same thing with epoxy.
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You should feel the same kinda creep or glue line at the other glue lines too then, Not real sure but I think it's moisture, I used to get the same thing In Illinois with a HBO I built, didn't affect the bow any just felt like the glue was squezing out. Out here where the humidity is just above 10% today that same bow is fine, you can't feel a thing.
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I agree with the eraly answers, it is just bending into the fade and the ipe is just too rigid to bend with it. Steve
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As much thicker as it is, and with a power lam, I cant hardly imagine it bending there. How long did youlet the glue cure and how hot was it when you were shooting. Justin
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I never stress TB 3 joints for at least 24 hours, and usually 48. It has been mid 80s during the day.
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I would say you wood wasnt quite at the same moisture level when you glued it up. Wood expands and contracts with the humidity/moisture level.
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I'd say if it is only happening with Ipe/Ipe joints, that the oils are coming out with the humidity and pushing the glue out. I've had TB3 have a fine skim that was trapped without air actually not set up when glueing oily wood that wasn't degreased real good.
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I have had the same thing happen in non bending areas on a bow and on a knife handle. It turned out to be a bad batch of epoxy. Have not had it with t b yet.
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I'm gonna try to de-grease the next ipe I use.
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Marty, If you look at handle you will see the glue is bulging out at the ends and not on the sides of the glued on section..This is from the bow limb bending into the handle. If this was a humidity or grease problem it would be on all sides of the grip, and not just where the ipe limb meets the ipe grip...
This can actually be a good indicator of when you need to get the limbs working a bit more, usually just outside the grip..Especially if you see this before putting the finish on...
Rich
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Rich's answer is good enough for me. I was flying by the seat of my pants with another option. ;D
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I don't really have a clue either Eddie. That is why I was asking questions. ;D It seems awful thick in the fades to be bending though since it has hardly started to narrow up. I thought the glue joint might just appear to be wider because it is cut on an angle there. ??? Tap the riser with a hammer. You should be able to tell from the sound if the glue is compromised. If it has been slipping like that it will probably pop right off. Justin
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This is not just visual folks. You can feel it. I would think that any glue would have set up by now! I would guess that its several thousandths of an inch bulging out. I have checked all my joints, and the ipe-ipe are the only ones doing this. I'm talking two different batches of ipe as well, which are quite different in color, if nothing else. Nothing has come loose yet, and I have several hundred shots through three different bows showing this problem. Handles glued with TB 3, and tip overlays glued with 2 ton epoxy. I really appreciate all that are helping on this one.
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Apex, because it is ipe to ipe the glued on piece is not flexing with the main part of the bow, just a very slight flex is all that is needed to cause this. Even on very thick modern risers they have some detectable flex. Sometimes a very thin slat glued on between the two like an accent stripe will stop this. Steve
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I see what you mean Steve. I never thought of that. That's why you and Rich get paid the Big Bucks ! I learned something.
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I learned something too Eddie. I guess I never had an issue like this because I always put something in there for color if Im building up a handle. Nice to have the big $$$$ boys around eh. Justin
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I glued one up the other day and the handle popped loose on me today. I used a jatoba strip between omy osage belly slat and the osage grip, not flexable enough I guess. Anytime I start with a 3/4" thick slat and the bow is close to 72" long and about 70# I find it real hard to keep a riser stiff. I think in the future I will glue a power lam between the boo and the osage riser on these longer bows. I know better but do it anyway?? Go figure? Steve
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I always glue on a power lam between the backing and core that extends to just past the handle when the core is a bit thin. This always cures any flexing problem
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The five highlighted qualities of urea based glues noted in this article scream, "BOW GLUE!". Read and see if you agree with me that Titebond, while convenient and readily available, may not be the best choice for laminated bow glue-ups. If you haven't heard of or considered it, Urac 185 is inexpensive and available through Neslon Paints website.
http://www.djmarks.com/pdf/ureaglue.pdf
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The glue I had let go on this handle was very strong epoxy. Used for high stress modern bow designs. If a handle is going to flex the glue won't help it much, maybe a little .
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Adam, I understand your view, but there's many glues which work for bows.and even Urac can't keep a glued on handle down if the tiller bends through the grip..no glue can.. If something goes wrong with a bow glued up with Urac, say the string splits the nock on the arrow and the bow dry fires, with urac the failure will take part of the backing with it. With titebond 3 it will most likely shed part or all of the backing cleanly, and you can glue it back on..I have done it a few times with great success..
Add in the high "net" cost of Urac, because of its short shelf life , plus you have to order and wait for it. Not to mention getting it on anything but the glue line creates a problem...I did well over 50 laminate bows with Urac, and since I have found several glues I like better, Titebond being one of them. The last batch of Urac I had went bad in less than 3 months, I called them up, and they wouldn't even give me the time of day... It was all I needed to hear...
Rich-
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I successfully repaired this bow with tightbond3. I shortened it a couple of inches to relieve some pressure off the handle and dropped the weight to 60#. Steve
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How thick should a powerlam be?
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I always glue on a power lam between the backing and core that extends to just past the handle when the core is a bit thin. This always cures any flexing problem
Marc, I always put one in too. This is why I am so confused on this. Look at the second picture. He clearly has a fairly thick power lam in that bow. That is why I cant imagine it bending. Justin
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Justin, I went back and looked and it does appear that the riser should be pretty rigid. I normally like my riser to be at least 30% thicker than where it starts into the fade and his appears more than that. I wonder if the shelf cut in might be allowing some flex. More than once I have tillered out bows and then cut in my shelf, then the handle popped or did what apex's did.
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I've really enjoyed the discussion folks. There is so much to learn from you guys with bunches of bows under your belts.
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Steve, that was all I could figure. Justin
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Yeah, I would agree with others about your bow bending into the fades.
However, Titebond does creep, I have noticed this with my raw boo belly bows.
I would always have problems with the fades sliding up and popping off.
It works excellent on other things such as backings and handles though,
I just think I will not use for fade glue ups, especially in my climate.
I just started using urac and I find it great to work with but it is more tedious to prepare...
Nonetheless, both glues works very good, just some are suited for different circumstances.
Alex
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I've had the same problem with TB3,glueing horn overlays.
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Eddie, Superglue is for overlays ;D let them dry for at least a half hour before working on them...
Rich-Loctite in the .18oz container
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Marc, I always put one in too. This is why I am so confused on this. Look at the second picture. He clearly has a fairly thick power lam in that bow. That is why I cant imagine it bending. Justin
I still suspect flexing Justin
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Try a thin veneer layer of something like maple in between the ipe layers. Sometimes that really seems to help the creep problem. I think that the veneer both hides the glue line and helps to buffer the rigidity of some of the harder woods.
Dan