Primitive Archer
Main Discussion Area => Bows => Topic started by: Stringman on March 18, 2013, 02:50:22 pm
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Well this build has given me fits before so I guess I should have expected it. Couple months ago the first handle started to pop off cause of not having a power lam in the riser. So it set in the corner for awhile and this last weekend I took it up to our Iowa jam and got some much needed help fixing the problem.
(http://i1311.photobucket.com/albums/s670/cotton7611/C3FFBFFB-F272-462E-9FDB-FF1D78949A23-495-000000E1072E2661_zpsbcf3e2b1.jpg)
On Sunday I began removing excess wood and getting it to bend. No problems and no sound from the limbs PERIOD. Had it moving along nicely and shot this pic.
(http://i1311.photobucket.com/albums/s670/cotton7611/2EBC8580-3B0E-4F6A-A8E0-963FC5512DC5-182-00000102F455E205_zps2cbf7def.jpg)
This morning I got the garage warmed up and picked up where I left off. The thing felt like a slam dunk! I couldn't keep my hands off it!
(http://i1311.photobucket.com/albums/s670/cotton7611/CD4174EB-035F-4052-BD87-3FA1F0AFF737-182-000001030282F3BC_zps4d3f03fd.jpg)
(http://i1311.photobucket.com/albums/s670/cotton7611/AF8626F3-596B-493B-BD51-FF8D3D2AA508-182-0000010309FD020A_zps42e44ad1.jpg)
I fiddled with the tiller a bit more and exercised the limbs a bunch. The string was tracking perfectly and the draw was smooth (but heavy.) I put a short string on it and had it pulling 55#@26". I went to bring it back a bit farther and BAMM!!
(http://i1311.photobucket.com/albums/s670/cotton7611/90EC13CE-ED2A-4D5B-B57B-C08ADA59EAF4-182-0000010310117CF8_zps44b3ed5d.jpg)
(http://i1311.photobucket.com/albums/s670/cotton7611/706A93C9-C797-47F3-9738-2297F37CF957-182-0000010318CCBCBC_zps56a313ea.jpg)
To say I'm disappointed would be a terrible understatement. I was already seeing the thing shooting arrows and couldn't quite reconcile myself with the 3 piece take down I was holding. Felt like a bad dream...
So what did I learn?? Nothing! Other than stop wasting energy on bamboo. If you have any insight please let me hear it cause I got nothing.
Scott
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That sucks. It was looking good. I think you should try again. Don't let it get the best of you.
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damn shame, some bows just aint meant to be
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looks like it failed in tension and only at the nodes. there must be something to that!
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looks like it failed in tension and only at the nodes. there must be something to that!
Improper tillering and he pulled it to far...!!! time and time again we go through this. ??? it's never fun breaking a bow with all the time we put in them.
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I don't see anything obvious. Two years ago I had 5 bamboo backed bows fail in a row. I finally gave up and tossed the whole batch of bamboo slats in the recycling bin. Recently I purchased a new batch of bamboo slats and started making backed bows again. So far I've made three without a hitch. Go figure...
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i have a feeling its the processing of the bamboo before you got to it.
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Improper tillering and he pulled it to far...!!! time and time again we go through this. ??? it's never fun breaking a bow with all the time we put in them.
I'm afraid I have to disagree... The only tiller shot I posted was from last night. I fixed most of the problem with that pic and felt like we were moving in the right direction. The limbs were flexing well and I didn't see any movement in the riser with just a freckle of movement in the fades. Obviously, it was a tension failure, but it looks like I put a knife to be nodes and cut them both at the same time. When in fact, I didn't even touch them there. I scraped up to them and that was it.
How bout this... It was bamboo, hickory, Osage belly, Osage power lam, cherry, and mesquite handle. Did the hickory cause this meltdown? Was the Osage too compression strong and the boo just couldn't hold up? I trapped and rounded the belly quite a bit to counter act this.
I know we have some brilliant laminant minds out there so lets here from you pros.
Scott
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looks like it failed in tension and only at the nodes. there must be something to that!
Improper tillering and he pulled it to far...!!! time and time again we go through this. ??? it's never fun breaking a bow with all the time we put in them.
I guess I'm not seeing the "improper tiller" you speak of. It's natural materials and being such, it doesn't always mean its the bowyers mistake that caused the failure. Natural materials are subject to unseen flaws that can and will cause failures even when the bowyer does everything right. To automatically assume the bowyer is at fault is a bit presumptuous IMHO. Josh
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looks like it failed in tension and only at the nodes. there must be something to that!
Improper tillering and he pulled it to far...!!! time and time again we go through this. ??? it's never fun breaking a bow with all the time we put in them.
I guess I'm not seeing the "improper tiller" you speak of. It's natural materials and being such, it doesn't always mean its the bowyers mistake that caused the failure. Natural materials are subject to unseen flaws that can and will cause failures even when the bowyer does everything right. To automatically assume the bowyer is at fault is a bit presumptuous IMHO. Josh
+1 especially if it was improved before it blew.
Jon
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IMO bamboo was WAY too thick. I make min a knife edge.. and have never had that happen. Infact last night I sawed the bamboo backing off 3 exploded bows. bellies shatterd but the boo was still good.
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all the bows that ive seen that are around 50-60 lbs have 1/8 inch thick bamboo. its got a tinsel strength very similar to steel. so you have to keep it thin.
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That sucks for sure....I've had bamboo pop up a sliver on me too.Seems like always from a node.Like GunDoc said it is'nt always the bowyers fault.It really is some great stuff though.The edges of the backs of bamboo on my bows are to a very narrow knife edge also.Except at the handles sometimes.There is'nt much more that I can say.The bend looks good on the tree too.
Looks a little like my sinewed red cedar that blew up on me a while back.
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That looks like a problem with the bamboo. Boo should not break like that; it should splinter instead of snap in half cleanly. I'm not sure what the problem with the bamboo is, but I think you should not use any boo from the same pole again. Possibly dry rot, fungus, bad drying or some sort of processing failure. I think this is beyond your control, so don't give up! You might want to switch to another bamboo supplier, or just use a hickory backing instead.
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Bad bamboo, broke to cleanly at the nodes to be anything else. I tossed a complete bundle of what looked like great bamboo I got from Frank's, every bow I made from it failed.
I tossed another complete bundle that arrived waterlogged and covered with mold. Didn't buy anymore from Frank's.
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Improper tillering and he pulled it to far...!!! time and time again we go through this. ??? it's never fun breaking a bow with all the time we put in them.
I'm afraid I have to disagree... The only tiller shot I posted was from last night. I fixed most of the problem with that pic and felt like we were moving in the right direction. The limbs were flexing well and I didn't see any movement in the riser with just a freckle of movement in the fades. Obviously, it was a tension failure, but it looks like I put a knife to be nodes and cut them both at the same time. When in fact, I didn't even touch them there. I scraped up to them and that was it.
How bout this... It was bamboo, hickory, Osage belly, Osage power lam, cherry, and mesquite handle. Did the hickory cause this meltdown? Was the Osage too compression strong and the boo just couldn't hold up? I trapped and rounded the belly quite a bit to counter act this.
I know we have some brilliant laminant minds out there so lets here from you pros.
Scott
Ok, i was only assuming it was bad tillering, I broke a few board bows, one obviously had some grain run-off.............but in all seriousness it was pulling over 60# if I had shaved more off in the proper areas and got'er down to say 50# the bow would still be intact.
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Bad bamboo, broke to cleanly at the nodes to be anything else.
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Clear as can be. See nothing wrong with tiller at that state. Just go for another.
Side profile looked BEAUTIFUL.