Primitive Archer
Main Discussion Area => Bows => Topic started by: Ryan C on July 17, 2016, 12:37:53 am
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(http://i296.photobucket.com/albums/mm165/jreefer454/8B6D2A41-D211-4B62-A8DA-1DFB96B7A7D9_zpsfnemmowy.jpg) (http://s296.photobucket.com/user/jreefer454/media/8B6D2A41-D211-4B62-A8DA-1DFB96B7A7D9_zpsfnemmowy.jpg.html)(http://i296.photobucket.com/albums/mm165/jreefer454/8908D178-8464-4C5F-8345-378F069516DC_zpso3d3x6se.jpg) (http://s296.photobucket.com/user/jreefer454/media/8908D178-8464-4C5F-8345-378F069516DC_zpso3d3x6se.jpg.html)
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Yep. Bummer. Josh
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what do you mean chrysals?
and hows that a bummer?
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It is. Sorry man. :(
what do you mean chrysals?
and hows that a bummer?
They are also know as compression fractures. The belly is failing under compression in those spots. The bow will eventually (or not so eventually) fail completely as the wood collapses in on it's self.
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Locust is kind of infamous for doing that. Do your best to learn "why" it formed fissures and you will learn a whole lot about bow making. I am not 100% certain from the pictures, but it could be your design didn't match the wood type or that during tillering you worked to quickly...as in you bent it too far on your tiller tree before the tiller was correctly balanced. Or, you left the tips to stiff and too much compressive force moved into the lower limbs. I used to often get these fissure right toward the handle area and realised that I was making the handle angle too steep and not gradual enough for some types of wood like black walnut to handle the sudden change in compression. That being said, you can keep on shooting it till it blows and see what happens. You might be surprised how long it lasts, or you might be disappointed. Either way, it'll let you know what chrysals can do to the bow.
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Yes they are.
As already said locust shows you quickly if you didn't tiller the bow correctly.
Tiller should match front view taper. Eg. pyramid = arc of a circle, parallel width limbs for a proportion of length should be elliptical.
Where the chrysalis are worst that the area that is working too hard. Areas on the limbs with none are under working. It is a shame all woods aren't like b.locust because you can't really get a locust bow wrong without it letting you know :) Some of the well known woods that are very eleastic and great in compression can let you get away with 'tiller errors'.
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@ Mike... if they get worse do they turn into butterflies? ;)
Del
(Sorry folks... pedantic joke... he miss-spelled chrysals as chrysalis.... ok I'll leave quietly :-[ )
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@ Mike... if they get worse do they turn into butterflies? ;)
Del
(Sorry folks... pedantic joke... he miss-spelled chrysals as chrysalis.... ok I'll leave quietly :-[ )
LOL!
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Good catch Del
It looks like the belly might not be completely flat, what you need with BL. Perhaps an un-braced and full draw pic would help us analyze your bow so we can make suggestions
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When the chrysals are localized to one spot that means the spot is bending too much there in relation to the rest of the limb. In other words, the tiller is off.
When the chrysals are happening over a larger area, all along the limb itself, then the design is off. The bow is too short or not wide enough.
Jawge
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(http://i296.photobucket.com/albums/mm165/jreefer454/97554EB7-FC96-479B-9BBE-9E3D392EB019_zpsjqgfmviu.jpg) (http://s296.photobucket.com/user/jreefer454/media/97554EB7-FC96-479B-9BBE-9E3D392EB019_zpsjqgfmviu.jpg.html)(http://i296.photobucket.com/albums/mm165/jreefer454/9A52394F-D7D4-49AF-86DE-BB8EF78C33E3_zpstsisbbaa.png) (http://s296.photobucket.com/user/jreefer454/media/9A52394F-D7D4-49AF-86DE-BB8EF78C33E3_zpstsisbbaa.png.html)(http://i296.photobucket.com/albums/mm165/jreefer454/F4B735A9-2CEC-4FD1-A8E8-7FB63FC6E417_zpsew6woenl.png) (http://s296.photobucket.com/user/jreefer454/media/F4B735A9-2CEC-4FD1-A8E8-7FB63FC6E417_zpsew6woenl.png.html)
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62 inch long about 1 1/14 inch wide only pulled to about 24" at th most
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There's one other aspect that results in chrysals...low quality wood. There's a lot of variance in wood within a species ranging from exceptional to firewood. 1 1/4" is possibly a bit narrow but you have the length to compensate. I'm guessing that you had a subpar stave. I don't think even mid-range quality black locust would have chrysaled at the point your at. Get another stave and get after it is the best advice I can give you. Josh
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well it is possible you overstrained the bow before the tiller was done,, it looks like the bow is bending a bit much out of the handle, and maybe that is it,, that looks like were the bow is taking set,, I am sure others will chime in,, but maybe get the outers working a bit more,, and next time try going a little wider,,,
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ah ok. kind of a strange name for compression fractures. but it makes sense now, i actually didnt know that wood could do that xD
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Wider will make it stronger but not protect against chrysals. Needs to bend evenly to avoid local failure. However, what about the rest of the limbs, are these the only chrysals, or are they all along the limbs?
I made a locust bow many years ago that wasn't dry enough when I made it. It chrysaled the full length. But I shot it for a year or more before it broke because I drew it too far. (BTW, it kept 3 inches of reflex until the day I broke it.)
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The bow looks well tillered. Could just be wood the is low in elasticity. If you have more of the same kind of wood then make the bow longer, as AA said wider won't help
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Ryan, you want to do a little experimenting ? I've an urge for you to try something on the bow.
I'll send you a PM. Fred