Author Topic: Problem solving?  (Read 3683 times)

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Offline Accipiter

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Problem solving?
« on: December 22, 2012, 03:58:03 pm »
Been working on the ocean spray bow again and have encountered a few problems that I was hoping you all could provide some advice on:




Problem#1  Before heat treating the belly I flipped the tips a bit, which was working quite nicely until one of them came out! I've already heat bent and treated that area twice, so I don't really want to mess with it any more. Is it ok to have an uneven profile? Should I take some curve out of the other one?



Problem #2 On that limb, the area where I put in the bend also developed what I think is a very small lateral crack, but since it is on the belly, I'm not too worried about it exploding. Should I be more afraid?!



Problem #3 (they're all related) Since one of the tips is more flipped than the other,  the tiller is a bit funky - not that it was perfect before. Any suggestions? Its pulling 44# at 25" now, which is where I want it (aiming for 45 or 50# @26 or 27") and weighs about 14 or 15 oz.

Thanks for your patience and advice!

Offline Carson (CMB)

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Re: Problem solving?
« Reply #1 on: December 22, 2012, 04:09:01 pm »
i am not that good at judging tiller on bend through the handles, but it looks like mid limb is a bit stiff on that left limb even accounting for that fliped tip, and maybe just above the handle area on the right limb is also stiff.  Looks like you are almost there. 

I would put super glue in that crack and not worry about it.  I wouldn't mess with the tip that pulled out.

Is the flipped tip going to be the lower limb?
"The bow is the old first lyre,
the mono chord, the initial rune of fine art
The humanities grew out from archery as a flower from a seed
No sooner did the soft, sweet note of the bow-string charm the ear of genius than music was born, and from music came poetry and painting and..." Maurice Thompso

Offline JW_Halverson

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Re: Problem solving?
« Reply #2 on: December 22, 2012, 04:11:10 pm »
Ok, Birdeater, that's a pretty looking bow to start with.  I love it. 

The cracking running across the belly is more of a problem than you are making it out to be.  It is called a fret, or stress fracture.  It shows that the belly is overwhelmed at that point and the wood cells have crushed and are failing.  You can do a Torges style patch, but you will also have to do something to the tiller to relileve that stress. 

I'm worried about telling you to heat treat that tip AGAIN for fear that it push the wood beyond it's limits. 

How does it shoot right now?  Imperfections and all?
Guns have triggers. Bicycles have wheels. Trees and bows have wooden limbs.

Offline Weylin

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Re: Problem solving?
« Reply #3 on: December 22, 2012, 05:44:23 pm »
I'm certainly not an expert on bendy handled bows but it seems to me that it is bending too much in the handle area and not enough mid limb and out. Anyone else see this or should I keep my mouth shut? The right limb looks better than the left limb. The left limb seems extra stiff at midlimb.

Offline Carson (CMB)

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Re: Problem solving?
« Reply #4 on: December 22, 2012, 05:50:13 pm »
Accipiter, was that crack the result of heat bending the tip?  Or did it develop later?  It looked to me to be some grain tear from putting in the bent tips with heat. 
"The bow is the old first lyre,
the mono chord, the initial rune of fine art
The humanities grew out from archery as a flower from a seed
No sooner did the soft, sweet note of the bow-string charm the ear of genius than music was born, and from music came poetry and painting and..." Maurice Thompso

Offline Weylin

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Re: Problem solving?
« Reply #5 on: December 22, 2012, 05:55:45 pm »
Hmm, In my experience when the wood cracks on the belly from heat bending it makes cracks running the length of the bow, not across. That's not to say, of course, that it couldn't happen but that's what I've seen.

Offline paulsemp

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Re: Problem solving?
« Reply #6 on: December 22, 2012, 06:02:57 pm »
I would say that you are asking to much out of that handle. I would take some off the limbs and glue and wrap the crack. I have done the same thing flipping tips, you need slower and longer heat.

Offline Accipiter

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Re: Problem solving?
« Reply #7 on: December 22, 2012, 06:44:56 pm »
Thanks for all the feedback! As to the crack, my inclination is to go with Carson. I don't think that it's a stress fret, because it happened when the wood was being bent backwards, not in normal compression. I think I just pushed it a little too hard when heat bending and had the grain tear on the belly a bit. Could be wrong though. Glue and wrap sounds like a good strategy Paul, and I agree with your assessment on the handle as well.

I will try and tiller to get a little more bend in that left limb and try to relieve stress on the bends by the tips.

And thanks JW, I like the half where the recurve stuck better  ;), but its still quite a bit better than my first bow! It shoots better too, but its really hard to emphasize enough how little that is saying.

Offline Del the cat

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Re: Problem solving?
« Reply #8 on: December 22, 2012, 07:03:17 pm »
I would say, learn from it and start again... I think the handle is working too much.
It looks like the bow could do to be wider and or longer.
Shoot the heck out of it, over draw it, make it work, see where the chrysals appear and learn from what you see.
Give it an honourable send off by shooting it until if gives out.
Del
BTW chrysalling bows tend to just loose cast and start to feel puddingy rather than exploding.
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Offline Accipiter

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Re: Problem solving?
« Reply #9 on: December 22, 2012, 07:21:59 pm »
Del, I think you've got the right idea about this one, on all counts! Will do.



Here a more or less full draw pic, looks a little more even to my inexperienced eye, but still too stiff towards the ends, no?

Offline Carson (CMB)

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Re: Problem solving?
« Reply #10 on: December 22, 2012, 09:26:15 pm »
You need halfeye to step in and judge that tiller.  Seems I have seen some of his bend through the handle bows also looking like there is a bit too much bend in the handle, but I know he builds them right.  Also, I don't think you are going to see any fretting in that bow...it is ocean spray! not some fragile second rate bow wood  ;D
"The bow is the old first lyre,
the mono chord, the initial rune of fine art
The humanities grew out from archery as a flower from a seed
No sooner did the soft, sweet note of the bow-string charm the ear of genius than music was born, and from music came poetry and painting and..." Maurice Thompso

Offline half eye

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Re: Problem solving?
« Reply #11 on: December 22, 2012, 09:51:38 pm »
accipiter,
       If you look closely at your fulldraw picture you can see where the lower limb is bending some but mostly near the grip.
       From my experience, evenly remove some wood from the entire lower limb from below the griup area about 6/8 inches on out and try to get more like the top limb which is bending evenly from grip to nearly the tip. You wont make the 2 limbs match but you will relieve the center strain that caused the compression problem (fret).
       For your future bend-through's dont leave the tips stiff. If you look at your full draw the outter 1/4 of the limb has some room to come back some more. If you even out the lower limb bend and bring both tip areas around a bit more it ought to be a rocket launcher.

     hope that wasn't too long winded but basically the secrete to a full circle is to get the tips moving.....both limbs bending fully, and THEN work the bend toward the center. If you dont go in that order, all the early pressure will be in the middle 1/3 to 1/4 of the bow and give that egg shaped draw profile....stiff tips on a bendy will also produce that egg-shape. If I didn't explain correctly please let me know, eh?
rich

Offline Weylin

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Re: Problem solving?
« Reply #12 on: December 22, 2012, 09:54:28 pm »
You need halfeye to step in and judge that tiller. 

Guess you just have to say his name and he'll magically appear!  ;D

Offline Accipiter

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Re: Problem solving?
« Reply #13 on: December 22, 2012, 10:12:42 pm »
Quote
Guess you just have to say his name and he'll magically appear!
  haha, I'll keep that in mind, what a fantastic explanation half eye! Thank you so much for the assessment and tips, I will definitely see what I can do, on this bow and in the future. I'm totally fine with coming in bit less than intended poundage, but it would be great to get that tiller correct so I have something to go on for the future.

Carson - I have abused the hell out of this stave, and it hasn't broken yet, pretty impressed with ocean spray for sure! I didnt even have any checking, which I've heard can be a problem.

Offline randman

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Re: Problem solving?
« Reply #14 on: December 23, 2012, 03:28:24 am »
I've had OS get tension cracks like that on the belly when I've tried to flip the tips also. OS does not like to bend much. Best results I've had is with steaming. That bow may be bending a bit much in the middle but it's Ocean Spray and like Carson said you're not going to have to worry about frets. Set would be the problem there. Has it taken any set in the middle, what's the unbraced side profile look like? If not, shoot the hell outa that one and make another. I also think if that flipped tip is at the bottom, that may be what is making it look stiffer and not bending as much. If you took that flip out and make it match the other limb, I think you might find the bend on the bottom limb matches the top better. Would have the effect of bring that lower tip around a bit more like Half-eye said without taking off weight (hopefully).

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