Primitive Archer
Main Discussion Area => Bows => Topic started by: cool_98_555 on July 17, 2018, 03:17:45 pm
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Hi guys,
I am having an issue here. I recently glued up a quad lam bow, put in a bit of reflex in the handle, and did my best to align the tips once the glue was dried. I have been tillering a little, and I noticed that the tips are about 1/2" away from center. The tips are at their final width right now, so I don't have any room to move the alignment of the tips. I could cut the nocks deeper, but im not sure how much correction that will allow. The string still tracks through the handle, but like I said, it is 1/2" off of center. It is really bugging me because whenever I pull it on the tree I can feel it want to twist in my hand a little. I haven't braced it up yet, but knowing these issues early on it doesn't seem like the string will track through the center when I brace it up. Any thoughts? I would love to heat it back into alignment, but being a laminated bow, that would be a really bad idea. I guess that's the advantage of working with staves; you can heat-correct anything you want. Anyway, what do you guys think? This is driving me crazy!
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The R/D I just finished had a twist in one limb. It has a Maple back epoxied on so I was shy of heat. I clamped it in my vice and twisted it quite a bit past where I wanted it and left it for an hour. It had moved a bit so I checked it again after two hours. It had moved a bit more so I left it overnight. Next day it was spot on and that was a week ago. it's still good. :) I was taking out twist and what you have may behave differently but it may be worth a shot
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Couple of options,aposing side nocks.it a!so takes very little heat on the belly to make a adjustment!I mentioned to do a mock up pic for another gent on here a while back,maybe I will do it now.
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Even one minute with a heat gun may work?here's my set up,right angle jig with a c and bar clamp.i place a wet cloth rag at the right angle to prevent the back being toasted!most expoxies are rated for 200f ,not nearly that much heat is needed from what I've seen.that being said I'm not a glue bow pro!
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I'd be careful with the heat gun. In my limited experience, even just a tad is enough to compromise the integrity of a joint.
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I would also be careful with heat & the Glue paticularly if its room temp cured , if you have enought width you could run a weighted string line down the center and re profile the front view or you could cut your handle more towards the string and beff up your handle wood with a added lam epoxy glues can be sensitive to heat even if you managed to move it you could compromise the joint just my 2 cents !
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Heat still scares me so I don’t think ill try that. However, i have it clamped past where it would line up through the center right now. I’m not sure if it will hold in the new position like yours did DC, but im trying it. I used titebond 3, not an epoxy. We will see...im crossing my fingers!
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Ok, that was my first question, which glue did you use? Titebond... I wouldn't do it. But just for future reference....
I use Smooth On epoxy and have made dozens of heat corrections with a heat gun, sometimes multiple times on the same limb and haven't had a single one fail YET. This includes corrections made to bows that were cured in my hot box with a 185 degree thermostat, and to bows cured at room temperature.
You don't want to get it too hot, try to effect to much bend in an isolated area, or force it if it isn't ready to give. For the type of correction you're talking about, I put the bow in the bench vise, held near the handle area, hang a weight off the tip, usually about 7 or 8 lbs, measure from the tip to the floor, then gradually heat the limb all around until it moves 'on its own' the desired amount. It usually takes about 10 minutes perhaps? Leave it there to cool.
I've also used the heat gun to correct limb twist in factory made full recurves, some vintage... a few that were twisted so badly that the string wouldn't stay on them. Corrections made with adequate heat stay put.
This heat correction option alone is enough reason for me to choose Smooth On over Titebond.
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I do heat corrections on my bamboo laminated bows all the time. I use smooth on. Not sure how well Tite Bond will hold up to the heat.
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Tite Bond will release at 150deg(F).
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Well I tried to bend it past where it needed to be, and it seemed to hold for a little bit, but soon after it went back to the original out-of-line shape :-K Maybe I will try my heat gun on the lowest setting....I don't know how else to align the tips.
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Are you allowing it to cool completely before stressing it?
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Do you have pics of the belly side of the bow?
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When i bent it I didn’t apply any heat, just let it sot for a few hours
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I had to let mine sit overnight but I'm thinking a twist might come out easier than a bend. It was worth a shot. You may have to try a little heat.
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Is the thickness even across the limb near the tips? You may be able to tiller the twist out.
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I would give it a quick blast on high so it affects the wood,not on low where it will penetrate to the glue line.also a small correction at the handle tranlates to a ton at the tips.
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I haven't braced it up yet,
I just noticed this. I wouldn't be chasing a 1/2" misalignment until I've got it to full brace.