Primitive Archer
Main Discussion Area => Bows => Topic started by: Knoll on August 22, 2014, 12:04:06 am
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Few pics of first effort to achieve Perry Reflex.
Supported tips using couple garden edging blocks.
(http://i884.photobucket.com/albums/ac48/knolltop314/Bow%20building/Perry%20reflex/100_2688.jpg?t=1408734990)
Eye screws placed into workbench, threaded string through those screws and over handle, and then used eye screws & string to pull bow handle almost down to surface of workbench.
(http://i884.photobucket.com/albums/ac48/knolltop314/Bow%20building/Perry%20reflex/100_2690-1.jpg)
'Bout 3" of reflex.
Spring clamps used to clamp backing to limb at tips.
(http://i884.photobucket.com/albums/ac48/knolltop314/Bow%20building/Perry%20reflex/100_2695-1.jpg)
Titebond II is adhesive. Used ace bandage as wrap to clamp along length of backing/limb.
(http://i884.photobucket.com/albums/ac48/knolltop314/Bow%20building/Perry%20reflex/100_2696-1.jpg)
Now to wait 24 hours, which seems like eternity for impatient person. Got my fingers crossed!
Michael
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Looks like you've got good reflex in it. Looking good, Michael.
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"Used ace bandage as wrap to clamp along length of backing/limb."
Hm......that's the first time I see this method. I doubt the bandage would apply enough pressure to clamp the two laminations together. What glue did you use? It may work with an epoxy, which tolerates small gaps. But a glue like Titebond really needs thinner glue lines. Why didn't you use inner tubes for clamping? That's a proven method which is able to apply more pressure.
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Was able to wait 22 out of the 24 that had promised self. After unwrapping, unclamping, and untying there was 1 1/2" of reflex retained.
(http://i884.photobucket.com/albums/ac48/knolltop314/Bow%20building/Perry%20reflex/100_2701.jpg)
(http://i884.photobucket.com/albums/ac48/knolltop314/Bow%20building/Perry%20reflex/100_2700.jpg)
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I was under the impression you were to tiller the bow to an even bend to around brace height, then glue up the backing in reflex. Otherwise the reflex achieved is not evenly spread throughout the limb.
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As long as you don't have big gaps along the edge of your glue line, I think it will be fine, especially for your first try. You'll come up with ways to make the next ones better and better. I do mine with the 30 C-clamps and Unibond, but I know of quite a few guys who use Titebond 3 and also use other methods for keeping pressure on the slats. I just used TB3 and an Ace bandage wrap to glue cherry bark to the back of an elm bow and it worked beautifully.
I could have put more reflex in the first bamboo backed osage I made as well. I left the belly lam too thick and was afraid it would crack if I put anymore pressure on it. It still turned out to be a good shooter and holds about 3/4" of reflex. Bottom line is, you wanted to put reflex into it and you did it. Now the real fun begins; you get to tiller it. ;)
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I am a little concerned the handle might pop off, I usually start with a 3/4" thick board at the handle.
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I am a little concerned the handle might pop off, I usually start with a 3/4" thick board at the handle.
I'm more than a little concerned. :-[
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well at least you are started,, what does not work can be refined,,,maybe if the bow was very light the handle might work,,,but badger has a good point,, also make the tiller bend more mid limb out,, with not much bend in the middle,, :)
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Badger's right; it's best to leave as much thickness in the handle area as you can so you can rasp into the belly wood at the handle fades. Sometime you don't need much though. On one of my tri-lams I'm into the belly lam less than 1/8" and the handle didn't pop off. It will help if you make the taper of your handle fades as long as possible. You only need 4" in the middle for your hand. I've found that it's easier to cut the taper on the handle block before I glue it to the belly. Start tillering that bow! :D
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Start tillering that bow! :D
It's too d@*& hot/humid!
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It is by me too. Last little bit of advice and then I won't bug you anymore. :)
You might be better off waiting for awhile and keeping your bow in a dry (like air conditioned) spot in your house before you start tillering it. Glues like Titebond must have a lot of water in them which raises the moisture content of the wood. The MC on my cherry bark backed bow went from 9% to 14% from the TB3 I used. And that's after putting it in a drying box for a day and a half.
Good luck with your bow.
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Will do. Thanks!
Btw, in case (when) handle pops on this one, there's another (albeit with properly designed limb/fade intersection) waiting in the wings. Wraps will come off it tomorrow eve.
Ya'll stay safe,
Michael
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Remove the wraps now. No need to wait longer than 24 hours to leaves any glue clamped. If you remove the wraps, the wood will lose excess moisture more easily as well.
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Remove the wraps now. No need to wait longer than 24 hours to leaves any glue clamped. If you remove the wraps, the wood will lose excess moisture more easily as well.
Got it. 24 hrs is approx how long 1st bow was wrapped. On unwrapping, glue lines looked good. So am using same ace bandage wrap technique for 2nd Perry reflexed bow and it'll be unwrapped sometime this eve.
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Been waiting for the temps/humidity to moderate. But since that doesn't seem to be happening anytime soon, couldn't wait any longer. Time to tiller!
Glued-up stick seemed to be sufficiently floor tillered.
Put on long string and, after a bunch of scrapes with rasps, seemed to be ready for low brace.
Here is shot immediately after bracing. Ntn distance is 52". Brace height is 2 1/4". Drawn to 12" & 24 lb.
(http://i884.photobucket.com/albums/ac48/knolltop314/100_2713.jpg)
My take is that right limb looks comparatively good while left needs work outer 2/3's, particularly middle third.
What's your take?
Thanks!
Michael
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Arm chair tillering here we go!
I think your seeing it right. But I would add this: (1) as you suggested start with a few more scraps from mid limb to the tip of the left limb, (2) once the left outer limbs is even with the right (and they're close already), continue to work BOTH outer limbs. Stay off the inner 1/3 of both limbs for a little while. The inners are bending pretty well (although a very few scraps on the inner right might be appropriate) and inner limb set is a cast robber. Looking good man!
Gabe
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More arm chair tillering, 'cause I know you enjoy the challenge!
This bow is 53" ntn with 1 5/8" fades and maintaining this width 4" and then tapering to 1/2" tips.
Objective is 25lb @24".
Reflex is down to 5/8".
Now at 4 1/16" brace height.
(https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-xpa1/v/t1.0-9/10606020_4505408049335_5791105581117964296_n.jpg?oh=fc70f2f538e4642260c81ecd31b3726e&oe=547EC7E1&__gda__=1416071011_0badb471d71384ca45aee79b0c0246b9)
4 1/16" brace height, 17" draw, 27 lb draw weight.
(https://scontent-a-ord.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/10620545_4505407889331_342499814791630113_n.jpg?oh=5492f5dc53b760fa2a121377b46aff88&oe=547D4ACB)
Michael
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The bend is not looking too shabby ;)
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It's looking really nice. Outer limbs are looking better. I think the whole right limb is a little stiff now, but perhaps the inner third more than the outer third. I would go super slow at this point. Rock on.
Gabe
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It's bending a little too much near the fades. The right limb is stiff tipward too.
Make your self a tillering gizmo.
For your glue-up next time either use a form and innertubes or tiller your lams to have a good bend before glue-up. The way you did the glue-up you were very lucky not to induce twist and those bandages are best suited to backing with rawhide not a hard backing.
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Made it to 18" draw with 4" brace and 24 lb draw weight . . . before . . . BANG!
Broke almost exactly mid-limb.
Appears that failure began 3" from fade and that it was wood, not glue line, failure.
Because I had not tapered fades into limbs' thickness, I had been purposely limiting wood removal for the 6 " limb length after fade ... trying to limit limb bending at fade and, thus, avoid handle popping off.
HA! Limb "popped off" instead!
Next perry reflexed bow is started. Quarter sawn ash as core w/ white oak backing. 58" length and 1 5/16" wide at fade. Objective being 30# at 26". Gift for The Wife's soon-to-be-90-yr-young uncle.
Michael