Primitive Archer
Main Discussion Area => Bows => Topic started by: WillS on March 22, 2016, 02:48:14 pm
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Any ideas? ;D
This one is a whopper of a knot, and it's ticking like a time bomb at exactly 27.5" drawlength, and opening up the crack you can see running vertically downwards. I'd like to get at least 29" out of it for safety, so open to any and all suggestions for ways to solve this. If it's solvable.
I'm also open to being told it's going to make a lovely walking stick...
(http://i1202.photobucket.com/albums/bb363/Will_Sherman/1936670_10153923870166427_59355833532765504_n_zps6iewreyq.jpg) (http://s1202.photobucket.com/user/Will_Sherman/media/1936670_10153923870166427_59355833532765504_n_zps6iewreyq.jpg.html)
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I'd just keep building and hope it stays within the bow.
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The bow's done, it just keeps cracking at 28".
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But does the crack leave the bow? Osage doesn't mid cracks providing they stay within the bow and not run off an edge
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I'd draw the bow too pen the crack, inject some thin super glue and let the bow down to close the crack. At least give it a shot...unless you really need a walking stick. ;)
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The crack is staying well inside the profile. Maybe it'll just run along the limb if it opens further...
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I think it will stop running, just a hunch.
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Only sure way.
Rasp it out into a long shallow scoop and lay in a patch of sapwood.
I've just done a similar thing on an all heartwood Yew Primitive.
Knot shown here:-
http://bowyersdiary.blogspot.co.uk/2016/03/heartwood-yew-improving-tiller.html (http://bowyersdiary.blogspot.co.uk/2016/03/heartwood-yew-improving-tiller.html)
Patch shown here:-
http://bowyersdiary.blogspot.co.uk/2016/03/knot-what-knot.html (http://bowyersdiary.blogspot.co.uk/2016/03/knot-what-knot.html)
If you want to keep the character you'll just have to risk leaving it, which will be Ok if the bow isn't too heavily strained. The bows I have with big knots like that I tend to keep as "show bows".
If I actually want a fix, the long shallow back patch works every time.
Make it about 4inches long and about half the depth of the sapwood so that some of the original sapwood remains continuous.
Del
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Does the crack touch the lip of the knot hole?
I'm not one for sinew or rawhide patches, just not my thing, but it could work on this bow.
If it were me I'd do as suggested and fill the crack with thin super glue. Heat the wood up a bit, bend the bow to open up the crack a bit and fill it up.
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Yeah it sort of trickles over the lip.
I don't like patches either. I don't like the look of bows that have them so I tend to find other ways to solve problems.
One of the problems here is that I can't open the crack at all! It's tiny - too small to get a fingernail in for example - even when braced and drawn partially. When I first spotted it (after hearing the tick at full draw) I flooded it with thin superglue and it just ticked again at full draw and the crack got slightly longer.
I'm wondering if it will just keep running along the bow further each time it's drawn to 28", or whether it will stop at a certain point and be stable until drawn further.
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Hmmmmm I don't like that it's over the lip.
All the tension forces are concentrated on that lip.
I've made a few bows that had knots/branches with the puckered lip sapwood around it.
I like to knock them down, id rather violate them and have them smooth.
Every yew bow I've seen fail (except one) have been tension fails around knots or concave sections in the sapwood.
I'd consider knocking the area down, sanding it smooth, sinew wrap the area once or twice, and leave the area a little stiff. Or just go for it, but you will flinch every time you draw it
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...I don't like patches either. I don't like the look of bows that have them...
If you do them right, they are virtually invisible.
Maybe do a try out on an old broken bow limb, you may be pleasantly surprised, it will look less bad than a load of sinew or thread.
It gives a good glue area, keeps the flow of grain and the line of the join all in line with the stress.
Del
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Sinew wrap. If you prepare your sinew fine enough you will hardly be able to see it. Burnish the sinew once dry.
Glue isn't going to do anything to help the bow.
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Sinew wrap. If you prepare your sinew fine enough you will hardly be able to see it. Burnish the sinew once dry.
Glue isn't going to do anything to help the bow.
Yeah that's my worry.
A wrap makes perfect sense, but annoyingly the crack is in a hollow just below that knot. I can't get any contact with a binding there at all. It's also not really opening up at all, so I don't know how much good sideways pressure from a wrap will help? Hopefully I'm wrong!
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My hunch is she will blow, I would put it on the tiller tree[where I could get back a bit] ??? and pull it to 29 and see what happens, ticks are usually fatal in my experience. ;)
Pappy
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I don't like your hunch Pappy :P
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I knew you wouldn't. ;) Just never had many if any that ticked that didn't at very least pop a splinter
and worst exploded. ;) :)
Pappy
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The back is in tension.
Any wrapping going around the bow will stiffen it a tad but won't add much in the way of increased resistance to tension along the back.
If you think it will blow anyway, why not try the patch?
Just think of the physics... just like the recent thread about butt splicing a bow. The unanimous opinion was an overlay over the joint. It worked.
You can lead a horse to water...
No more from me on this thread... honest, yes, really....
Del
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That is a giant crack. I'd superglue it and I'd do a sinew wrap to the end of the crack.
When I tiller a knot, I leave the knotted area a little stiffer than the rest of the limb.
Jawge
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Nothing left for me to say about possible fixes, all my heroes have chipped in.
I just wanted to ask for more photos, preferably with the rest of the bow. That one pic was a tease!
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Try drilling a hole right through the limb (thickness) where the crack stops. It cant get past that hole and that hole wont hurt the bow.
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Try drilling a hole right through the limb (thickness) where the crack stops. It cant get past that hole and that hole wont hurt the bow.
Oooof that's a brave idea! The logic makes sense. Might need a new pair of undies...
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I see no reason it wont work! The hole only needs to be a 2-3mm at most.
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Nothing left for me to say about possible fixes, all my heroes have chipped in.
I just wanted to ask for more photos, preferably with the rest of the bow. That one pic was a tease!
Fine :D
These aren't finished photos - the tiller was tweaked and the bow oiled since but this should give a rough idea. I don't usually take full draw photos for various reasons, but I'm getting nagged to death by people about this one, so I might take one later and add it in here as well.
It's English Yew, somewhere between 50 and 60lb at 27" (or 28" with a deadly-sounding ticking soundtrack)
(http://i1202.photobucket.com/albums/bb363/Will_Sherman/Mobile%20Uploads/IMG_20160322_123654978_zpsnwirnzue.jpg) (http://s1202.photobucket.com/user/Will_Sherman/media/Mobile%20Uploads/IMG_20160322_123654978_zpsnwirnzue.jpg.html)
(http://i1202.photobucket.com/albums/bb363/Will_Sherman/Mobile%20Uploads/IMG_20160322_123826_zps9crq8sgr.jpg) (http://s1202.photobucket.com/user/Will_Sherman/media/Mobile%20Uploads/IMG_20160322_123826_zps9crq8sgr.jpg.html)
(http://i1202.photobucket.com/albums/bb363/Will_Sherman/Mobile%20Uploads/IMG_20160322_123845_zpsexe1fj2b.jpg) (http://s1202.photobucket.com/user/Will_Sherman/media/Mobile%20Uploads/IMG_20160322_123845_zpsexe1fj2b.jpg.html)
(http://i1202.photobucket.com/albums/bb363/Will_Sherman/Mobile%20Uploads/IMG_20160322_124151_zpsgtbjjtcy.jpg) (http://s1202.photobucket.com/user/Will_Sherman/media/Mobile%20Uploads/IMG_20160322_124151_zpsgtbjjtcy.jpg.html)
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I see no reason it wont work! The hole only needs to be a 2-3mm at most.
Has it been done somewhere I can see it? Sounds like an amazing fix, but I think seeing a successful bow with it having been used would ease the nerves a bit!
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Glass bow guys do it all the time. The truth of the matter is glass will act the same way when a crack starts. Plus, looking over your new pictures I doubt a 2-3 mm hole will even be noticed by that wood!
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Interesting. Cheers for the idea - I'm gonna give it a go, and wrap as the other guys suggested as well! I only need one extra inch of draw to be happy enough to sell this one so fingers crossed!
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Thanks for the photos, Will. She's quite the character and I am sincerely hoping she works out for you! Wow, what a looker!
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A wrap wont do anything but make your beautiful yew bow ugly!!! :)
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never sell a bow that has issues,, :) or that you have to cross your fingers ;)
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Very true! This one (if I think it's OK) will go to somebody I know, and I will be making sure they're aware of its limits. It's a great little bow already at 27", I just need to make sure it's safe to around 30" for safety margin. Otherwise it will stay on the wall.
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never sell a bow that has issues,, :) or that you have to cross your fingers ;)
Or even give it away. The only way you can likely get it to the owner with a clean conscience is say that you are throwing it out since it's not safe and put it out with your garbage and have him pick it up there. Free.
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I agree. I would not sell it. Jawge
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'Glass bow guys do it all the time'. Is that right? All the time? Why would a glass bow get a 'check' or 'crack' in it? It would have to be a mightly badly made bow by someone who doesn't understand even the basics.
Please explain the physics of why a wrap won't help stop a split getting worse. I'd love to hear some more pearls of wisdom.
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I know i'm going to try it on some arrows.....a hole right below the nock slot and of course no wrapping to resist the splitting forces....man i'm going to have me some beauty arrows ;) ;)