Primitive Archer
Main Discussion Area => Bows => Topic started by: armymedic.2 on July 19, 2007, 12:23:54 am
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i am beginning tillering on my second bow, and i can't help but wonder how much support the backing really gives. i am using hickory with a one peice boo backing. 72 inches ntn. it will draw about 60 in the end if i do my part. so my question is, say i don't tilller perfect, what is the likelyhood of the bow breaking? the grain is good. i hear a lot of selfbow guys talk about their bows breaking, but rarely hear of a backed one doing so. or i hear a self bow has a crack in it, so they back it to solve the problem. is it really so strong as to not worry about a crack in the limb? not really sure what to think- just a little insurance but not much, or nearly a gaurantee of service. let me know your thoughts.
ps. my first bow was re oak board with fiberglass backing three layers filled with titbond 3, pulling 60 lbs. the bow made a tick noise a couple of times, and i put it away for fear of it breaking. i probably shot it about 75-100 times. shot great beyond the hand shock of overbuilt limb tips. the tick may have been from the string on the new poly finish, but i could have sworn it felt slightly easier to pull immediate;y after the tick. since i put it down i never broke it. was i overcautious or right to think it would break.
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Army, when you talk about a boo backing or a hickory backing you are talking about a whole different thing than just backing a bow with something like rawhide or linen. The bamboo becomes about 1/2 your bow. You still have to do a decent tiller or it will break. Bamboo is probably one of the stronger backing choices. With a fairly good tiller you should be fine. Steve
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As Steve said, boo is very strong. Be careful of hinges as the boo will accentuate them. I hinged a boo backed hickory a few years ago. I think that boo is better suited for heavier belly wood like osage and some of the tropicals. A boo backed hickory bow can be built but I don't think it is a good choice for a second bow. A hickory self bow would be less complicated to build and if you are in a dry climate will be capable of out shooting many other bows. If you only have hickory boards to work with a simple silk, linen or even brown paper bag and TB glue will help prevent any splinters from lifting on the back or edges. Most of all, have fun! ;D Pat
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We've has great success using polyester camo net as a backing ...works great on wood(not boo) and we've yet to have a failure... if you're in doubt , two layers is even better .... and it looks good too... great camo in the woods and much easier than chasin' down a snake ... safer too ... ;D Tightbond II holds it securely even our very Damp climate...we glue it on the bias for extra strength...
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We've has great success using polyester camo net as a backing ...works great on wood(not boo) and we've yet to have a failure... if you're in doubt , two layers is even better .... and it looks good too... great camo in the woods and much easier than chasin' down a snake ... safer too ... ;D Tightbond II holds it securely even our very Damp climate...we glue it on the bias for extra strength...
Well now that's primitive :o
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I think that a good philosophy for a backing is that it adds a little insurance to keep the bow from breaking. Sounds simple. No backing is 100% though. i can't discuss wooden backings as I have never done one. I'll list and discuss some. Sinew-the strongest and toughest. Time consuming to install. Requires patience in waiting for it to dry. Excellent protection. Adds reflex to a bow. Rawhide-love it. Easy to install. Tough. Excellent protection. Burlap -easy to install. Fair protection. Silk -easy to install, fair protection. Having said that my favorite backing is air. In my view a beginner should find the best piece of wood. Tiller it as perfectly as possible and then back it for added protection. Jawge
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With a hard backing like boo or hickory, ring grain/ring orientation takes on much less importance because the tension is now spread across the backing piece and the core only has to compress. With boo, an occasional problem is a splinter coming up at a node, usually an indiscernable defect in the material having nothing to do with your efforts. The other problem would be delamination, i.e. the glue letting go because of some defect in the glue-up. If you make enough bows, you will probably run into both. Butu go forth boldly.
Dave
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Marc ..."keep it flexible "... ;D bows or attitude ???
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I do glue ups of Hickory backings and other woods. Works great and you do not have to worry about violating growth rings since the wood is under compression only and not tension.