Trad Gang
Main Boards => The Bowyer's Bench => Topic started by: bowhntineverythingnh03743 on May 12, 2015, 05:31:00 AM
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Hey guys-
Been forever since I've been on the site posting due to work schedule changing and turkey season being upon us. Anyways, I am going to be crafting a short recurve like our ol' buddy Trux does. I have made the form and started to shape the riser for glue up. I spliced my taper lams together to start and fit it before glue up. I want to makes sure that everything is tight and I have no glue lines.
The problem I am having is that my spliced taper lam is popping apart at the glue joint. Trux instructed me to make a longer splice which I will do but was wondering could I heat the lams up with a heat gun to help settle them into the bends. I figured since I pre shape osage billets for a tri lam could it work with this issue as well. My lams are maple by the way if that makes a difference and the but end is .080.
I'll put up some pictures as I go along with this build.
Thanks
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Do I know you? :)
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When I built my shorty -- similar to but not the same as Trux's, I actually hot water soaked the wood lams and dried them on my (Open top rubber band style)form before glue up.
You can also try using more, thinner lams. Anything thicker than about .040 can have problems making extreme bends (I also build wood-glass composite Scythian bows with extreme setbacks and recurves).
(http://i21.photobucket.com/albums/b282/kenhulme/TwoBows_zps5bf772f5.jpg)
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i bhad the same problem, when i way laying up my short static recurce.
so i did 2 things:
1.i made a short- about 6" longer than the riser( 3 each side) mock up stack( just the back stack- not the stack on the belly.
so same lams, tapers, and a piece of 030 wood to simulate the glass thickness. and i glued it all together down into the form- so i now had a simulated back stack, that was the right shape( well it did spring back marginally- but was good.
so now i had a proper shape profile that i could squeeze down into the form, while dry fitting the riser- and doing the final touch ups- lam splices werent stressed a hundred times, and it was an exact fit!
2.when i came to do the glue up- i use the wooden dowell /toothpick technique- (gotta ask your new friend- the ol' fella. hes gettin on- and every day he wakes up with his wife, he fuggers its a whole new romance all over agin! :laughing: )
so i pin all the lams and glass- then right over that pinned area- / center of the riser /lam splice area,
i taped the lams to the riser, so that would stop them flexing away from the riser as i was squeezing them in- cos for me, that was what kept breaking my splices- just too radical of a bend on those shorties- unlike the longer bows.
i really pulled it down hard with the tape and got it really tight and snug- messy job- glue everywhere- but stopped it from breaking.
does that make sense?
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Can you use a single piece lam? This is how I make all of mine now to both avoid the look of the splice and make it easier for glue up.
(You may need to make a barrell tappered sled, but that is not all that difficult)
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Brad, would it be practical to do a one piece lam by tapering each end separately?
This question coming from a guy who has yet to build a tapering device!
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yup, you just need a long sled, as brad said- it will have a kinda "barrel taper"
do you have any taper sleds mike, and a drum sander- or some way to grind your lams.
its real easy to make the sled Brad is talking about.
one of us could talk you thru it , if its the way you want to go. :)
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too answer your question Mike- never tried that- but i would think it would be do-able!
just take twice as long, but time is not the real issue. only thing i would watch, is that the "un sledded lam, is not touched by the sanding drum at all- which is kinda obvious- and sure you had that figgured out :D
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Longer splice and better glue. Splice yur lams with smooth-on and they won't come apart. No need to heat cure for that. Just give them a day or two.
I've used 5min epoxy for splicing and that works well too.
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Are you attempting to splice the tapered lams together? I use the parallel on the back of the bow on my shorty and put the tapers on the belly side. I haven't had any problems so far with the lam popping apart. Probably just jinxed myself.
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Well... This all sounds fine and dandy, but us less experienced part timers need some pics! Lol. Could you more seasoned vets illustrate?
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Thanks guys... Not sure what to do here as I have the lams already made. I guess I could order a new set of lams for the tapers and cut the thickness in half for each set and have three instead of two. I will ponder this and see what I come up with. I need to start hammering some bows out because it has been a while since I have built anything and I don't even have a single bow of my own.
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Originally posted by LittleBen:
Longer splice and better glue. Splice yur lams with smooth-on and they won't come apart. No need to heat cure for that. Just give them a day or two.
Ben nailed it, Smooth-on....
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Thanks for the endorsement Thad.
I've had this problem also because I use all spliced lams in ,y tri-lam builds, and the backing might be as thick as .150" at the butt end where it's spliced. Bending that over a forward riser handle can be tricky. Like I said I use epoxy to splice, and I also use a 1/8" oak pressure strip, and place a clamp (or two) directly over the splice that way it doesn't pop open ... Just like you're trying to prevent splintering. If you're using a hose for, this might not be helpful.
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i agree Ben, i have moved away from CA glue, to smooth on as well!
takes a bit longer, but it doesnt pull apart!