Author Topic: Laminating flipped tips  (Read 3148 times)

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Offline Kegan

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Laminating flipped tips
« on: November 27, 2009, 12:49:17 pm »
Okay, say we have a normal flatbow with about 1/2" wide tips. If we narrowed those tips, they would begin to bend, reducing efficiency. If you glued a thin belly lam underneath them though, whil imparting some Perry-reflex, the tips would stiffen up.

Now, if you reduced them down to just over the minimal wood amount, would they be lighter than otherwise because the glued in Perry-reflex? Something along the lines of siyahs. Light and nonbending.

The stiff lighter tips would be enough to boost performance, but would the now laminated tips be lighter than otherwise- or would this be to marginal to notice?

Offline Pat B

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Re: Laminating flipped tips
« Reply #1 on: November 27, 2009, 03:34:47 pm »
Kegan, I make tips thicker than normal but narrower to keep the physical weight down.  Adding an overlay could be lighter if the overlay wood is lighter than the bow wood...and you have to figure in the weight of the glue. Just the fact of laminating will increase the strength more that the sum of the two parts. You could kerf the tips horizontally and add a thin(same width as kerf) spline and get a stiff tip without adding much if any weight. I've seen static recurves done this way so they won't pull out. 
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

radius

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Re: Laminating flipped tips
« Reply #2 on: November 27, 2009, 03:38:20 pm »
Kegan, i like that idea.  Giver and let's see what you get.  I did 2 bows with belly tip underlays this year, both steamed into recurve first.  You are talking about reducing the wood so much that you can bend, say, the last 6 inches around a bottle or whatever, and get ur self a perry-style recurve.  Like it.  Do it, let's see!

Offline Justin Snyder

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Re: Laminating flipped tips
« Reply #3 on: November 27, 2009, 03:47:34 pm »
Yes, get it done. The general rule is twice as wide is twice as strong, twice as thick is 8 times as strong.  According to my math if you narrow it from 1/2" wide by 3/8" thick to 1/4" wide, you only need to add 3/64" thickness to get the strength back. Even 3/64 X 1/4" of Ipe is lighter than 1/4 X 3/8" of a balsa wood. Lateral stability migh become an issue at some point though. 
Everything happens for a reason, sometimes the reason is you made a bad decision.


SW Utah

radius

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Re: Laminating flipped tips
« Reply #4 on: November 27, 2009, 03:49:20 pm »
bend it into reflex adding both an overlay and underlay of 1/16.  It'll be plenty thick, no problem  (haha, blind encouragement!)

Offline Jesse

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Re: Laminating flipped tips
« Reply #5 on: November 27, 2009, 09:01:42 pm »
Kegan I was kinda thinking of the same thing for a bamboo back and belied bow Im working on. It already glued into r/d with a boo back and is tillered out. I was thinking of thinning the ends enough so they bend easy before applying the boo belly and reflex the tips more at glue up to hold the shape and it should be plenty stiff. I think bamboo would be something to consider using on your project. Nice and light :)
"If you can find a path with no obstacles, it probably doesn't lead anywhere."
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Offline medicinewheel

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Re: Laminating flipped tips
« Reply #6 on: November 28, 2009, 03:15:37 am »
I've done that once with good success on an ash bow. The recurves where steam bend, I don't think the Perry reflex would do anything different. It might be difficult to accomplish a Perry reflex anyway due to the very short curve of relatively thick wood; for a Perry reflex sort of thing you could do a horizontal cut and use an inlay (Dean T shows how to do that in the BBO video)



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Offline Kegan

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Re: Laminating flipped tips
« Reply #7 on: November 28, 2009, 02:32:23 pm »
Thanks all :). I've a few bows in the work that seem like, even with hevy heat, might not be able to stay stiff. As I was consideirng just adding a lam to it, I started thinking about the whole thing.

i'll give it a go and see how it works :)