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Main Boards => The Bowyer's Bench => Topic started by: breazyears on July 27, 2016, 02:46:00 PM
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Well this id a first for me. I was drawing this bow back and i thought i heard a ripping noise. I thought, maybe it was the arrow on the shelf??? So i drew back a few times more and...BANG.. The top limb exploded. Or snapped right at the fade.
Any guesses as to why?
https://imgur.com/a/BLzPs
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Sorry to see that happen on such a good looking bow, well any bow for that matter. I've never made a laminated bow so can't be of much help as to what caused it to break. Hope you get it figured out.
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Oh wow, that's terrible sorry that happened, good looking riser btw. No idea as to why. I noticed that in my garage where most of my bows are hung it has been hitting 100 degrees! I have unstrung several from fear of this.
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That is to bad, all that work I can see you put into it. Was it a glass laminated bow?
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Id guess it de-lam'ed and once the glass stopped holding the wood exploded. That sucks.
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Was the wood oily? Looks like glue bond failed.
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Ouch.
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The ripping sound was likely the glue letting go.
That's too bad, it was a nice looking bow.
Dave.
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To bad but, it does happen now and then. Don't let it get you down happens to everyone on occasion.
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bummer dude! Do you degrease the fiberglass before glue up? Never made a glass bow ...
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I clean the glass with acitone.
I triés to conserve glue on this one. Usually i use way to much. Think ill go back to usine lors.lol.
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Uhg! That looked nice...
Yeah, your glue bond failed imo. Starved joint may have had something to do with it. or poor adhesion for some other reason.
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I don't think it was a glue issue. A glueline under pressure is very thin, unless there are actual dry spots when you clamp it up or you used mega force on c clamps etc it is very unlikely to be 'dry'. did you coat both sides of all lams?
what I suspect is that it simply didn't have enough 'meat' around the sight window to keep it stiff enough there. Did you have a glass I-beam in the riser? If it is just wood that is your answer. How close to centershot was it? What woods did you use in the riser?
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No the bow did not have an i-beam. I dis butter both sides of everything, the Woods uses were cherry, and jatoba. The bow was cut about 3/16 from centre.
Not sure why it would let go et the fade because of a weak riser??
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I don't know, but it makes me sad looking at your beautiful bow like that..what glue did you use? what grit did you sand tapers to?
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Smooth on...80 grit.
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Because it is flexing (left/right)in the base of the sight window. I've seen this before on two different bows so am pretty confident. It is easy to forgot when cutting in sight windows that you are making a large stress riser and a weak point. Stress riser concentrate stress....and you are also at the weakest spot in a bow without an I-beam, combine these two factors and it is a good idea to add an I-beam of something bombproof.
If you look then at the base of your sight window it is made up with a large proportion of cherry instead of 'bulletwood'. Cherry isn't a stiff or very strong wood. The maximum strain on any bow is out of the fades.
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how long is the bow?
what taper rate?
riser length?
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So Mike, you speak of the stress added to the fades because of the sight window. That makes sense to me, especially when taking the characteristics of cherry into consideration. With his particular wood choices, would just adding an I-beam of something bombproof (super dense wood, micarta, or glass) to the riser be enough to reinforce that particular area?
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Ya,
Mike, i got thinking about it last night and i beleive you are exactly right. From now on it will be proper woods. I dont like the look of an i-beam.
Thanks for the replys fellas.