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Main Boards => PowWow => Topic started by: ItzaKen on April 09, 2022, 08:53:34 PM
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I need opinions and suggestions... about this/another bowstring!
My bow is a Great Northern Bush Bow, 62", 50#@27".
My string is 12 strand B55 w/ 14 strand loops.
Why did my string fail and why on one side?
I'm assuming I have too few strands in the loop; how many should there be?
Could this be an issue of uneven pressure, when twisting?
Thanks, All
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You may have a sharp edge on your string nock but more likely the string is rubbing on that side every time you draw the bow. I have had some bows that just eat the B-50 and B-55 materials and it can be very difficult to figure out why. I use padded loops and they last much longer but that didn't work, I see.
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Sharp edge.....
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This bow is approved for Fast Flight, so maybe I'll just go with that.
Possible sharp edge: Specific suggestions, please.
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Look for a sharp edge and if you find one, go over it with 400 grit sand paper. It's also possible you got some grit in the string loop. That's more likely to occur on the lower loop, caused by leaning the bow against something and digging the lower limb tip into the dirt.
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The lower loop is also showing wear on one side; I'll see if I can figure out which way this loop was attached and check out the nocks.
Thank you!
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Loops should not have to be built up on that 12 strand B-50.loops are primarily built up on skinny FF strings to provide cushion and better wear overtime.
Could be a sharp spot or rough spot in the string groove thats causing friction as mentioned above.
Maybe something just happened to the string that you are not aware of and it caused it to be comprimised.So you may have no problem with your grooves at all.
Try another string and just keep an eye on that area and see if the same thing happens or starts to happen.
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I saw your bow had tip inserts and I dont think it has tip overlays?It appears that way
The place where it looks like thier may be a sharp edge possibly is on the back of the limb where thier may be too much of a 90 degree angle that may create a sharp edge.Maybe that could be rounded off.Just speculating.How old is the string and has it been shot alot?Maybe it was time for a new string.
Cheers
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Correct! No tip overlays; it IS made with them, now.
So, just round the edge down a bit, on the bow's back (not belly)?
I made this string, only a just weeks ago!; I've only been drawing my bow to get my strength back, so this is wearing through, very quickly!!
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I would ask how old that string is and do you keep it waxed .
I find on my hill ASL , the bottom loop especially but also the top seem to, for lack of a better term , dry rot over time, Also normal wear and tear. Wet weather, tips resting on the ground etc.
Get a new string and keep it waxed
Kevin
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I had the same issue with one of my longbows...after the second string did the same as the first I took a chainsaw file to the groove just enough to relieve the angle a bit and all was well :dunno:
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That does not look to be an ancient string. It does not even look very frayed. It looks more like a cut, than a rub.
I would guess that you have a rough edge somewhere. It does not take much for a string under that much tension, to be compromised. Something else that can cause that, is a lack of finish in the string grooves. It's easy to miss the grooves when spraying finish, as you need to be careful about too much built up and drips. Dry material can be very abrasive. If you do find a rough spot, be sure to get some finish in there after sanding it VERY smooth.
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After I clean and lightly sand the nocks, what finish should I use? Please be specific, as there are so many products out there!!
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Best thing would be to use what the Bowyer used. If you can't get that info, then I would be inclined to assume its a solvent based finish and would get some rattle can polyurethane and do a couple coats. Not sure what is available where you live, but Minwax, Defthane, or some other national brand would be fine. I would not use any water base finish or 2K. Tape off for overspray and make sure the finish is smooth after it cures. :thumbsup:
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Thank you for specific instructions!
I DID, just email the bowyer, this morn and will twist up a new string, with more strands and will clean and polish up the nocks, first.
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I had a similar issue with my recurve, years ago. Smoothening the tips did not help. I am still not sure of the cause.
In any case, I went to a cobbler and got the tips covered in leather. It worked very well 😄👍
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Try running a Q Tip around the string groove. Anything rough will pick up some of the cotton. If you're not actually shooting the bow I would suspect a small piece of fiberglass protruding. It doesn't make much at all to eat the string through. And as said dirt and to sharp of a edge will do it also, that usually takes a bit of shooting though to wear trhough.
If I'm knocking off the sharp edge I'll use a chain saw file or other files I have. But either way I'll use a small piece off wet/dry fine grit autobody sand paper rolled up tightly to finish of the string groove before resealling.
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ItzaKen, I see you're in Oregon,
Bring that bow to the western states trad rendezvous in Lagrande. We can figure it out there with a couple hundred other bow hunters. :archer2:
Kevin
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Thank you, Kevin!
I'm in Springfield/Eugene, OR and it's 370 mi, one way... ;=)
Probably won't make it over, but I appreciate the offer!!
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Ok that's cool,
Not for nuthin but I'm driving solo 300+ miles to support YOUR state organization. :goldtooth:
Just saying , YOLO right. If tomorrow never comes ?
I just need to get out and associate with my bowhunting brethren and camp n shoot.
Recharge my batteries . closest I can get to September until September.
Kevin
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I tested the nocks for whatever, with a teased, cotton swab; nothing.
I cleaned the wax and crud out of the nocks and retested; nothing.
I'm twisting up another string and will round off everything with a little sandpaper. I won't have results for a couple of weeks of drawing the bow, but will get back and post results.
Here's the suggestion/recommendation a bowmaker sent me:
"I would just use some 320 grit sandpaper and make sure nothing is sharp in the grooves. I wouldn't worry about finish unless you think you sanded into the wood substantially. Our finish is an epoxy finish similar to Thunderbird. Small defects just use a drop of super glue to seal."
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Question: Has anyone served the 2-3" that will become the loops, before continuing the making of the Flemish loops??
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Never have for a Flemish string but that is how endless loop strings are made.
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This may sound silly…. But have you checked how the limbs are tracking through the draw cycle? Just hook the grip on a door knob on an open door and draw the bow and watch what the limbs are doing as you bring it to full draw. Then switch and hook the string on the door knob and watch the back of the limb.
Sometimes a limb will develop a slight twist that you can’t see until you watch the limbs as you draw the bow. That would definitely put more pressure on one side of the string loop.
I would also recommend going to a D97 fast flight string with padded loops.
Kirk
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Interesting idea, Kirk. I can't imagine how/why a lam bow would do that and would be happy to hear how and what any remedy might be!
Yes, I AM ordering some D97.
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Brother.... You would be amazed at what some of these bullet proof glass bows can do under the right conditions. Just having a string sitting off center in the string grooves and leaving it in direct sun light for a couple hours can develop a slight limb twist. Heaven forbid you leave a bow strung up in a pick up cab in sunny weather. I've seen them come apart doing that...
With flemish twist strings, sometimes just flipping the loop 180 degrees can make the difference on a slightly twisted limb making it worse, or straightening it back out. This isn't a reflection on the string maker at all, it's just the nature of the beast using a flemish loop.
I think the first time i realized this was while i was building a light weight set of recurve limbs that i had too much forward taper in the core. These limbs would go sideways on you if you breathed on them wrong. Seriously sensitive to perfect string alignment. I finally got it tracking straight and setting in the string grooves nicely. So I finish sanded the limbs and strung it back up only to find i still had a slight limb twist. That's when i tried flipping the loop 180 degrees.... BINGO! I was back on track.
For you guys out there that have a slight tracking issues on recurve limbs,or a wee bit of limb twist at brace, i'd strongly recommend trying flipping the loops 180 before trying to straighten a limb.
Another thing that can foul up your tracking and cause limb twist is having your loop too tight on that bottom limb, and not checking it closely after you string it for laying dead center. This can even cause problems for bows with excellent stability qualities too. I always order large loops both ends on my flemish twist strings so they self center easily and rarely bind up in the string notches. .02 cents worth...
Kirk
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WOW!! So much, I did not know!!! Thank you.
What do you mean by "too tight" on the bottom nock? I try to make my loops small, so they don't fall off, when the bow's unstrung....
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"I make my loops small".....
Like several mentioned, a sharp (or less rounded) edge across the groove path, along which the string loop follows, is very common. But, also, a smaller string loop, naturally, lays the string more acutely around any sharp edge. A more acute string angle (due to the smaller diameter loop) over any edge increases force between the edge and string. Greater force over a smaller area (edge) = increased pressure. Increased pressure cuts strings. A larger loop would decrease pressure, due to its obtuse angle, but the real problem is usually a sharp edge perpendicular to the string, how/where yours is cut.
I like smaller loops, too, but without a sharp edge, small loops are not a problem. Scissors cut strings really well, when that string is bent around its two edges.
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Very interesting explanation! I'm in the middle of twisting up a string, right now and just finished the bottom loop. I'll slip this over my limb tip and play with it to see what you're talking about. I have yet to sand/round the nock edges.
Thanks!!
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I have a PSE Heritage longbow that does that to strings. I build a flemish twist and then wrap the loops with dacron. Kind of winds up looking like an endless loops string. They last forever this way, just one extra step and a bit more weight, but I killed a few critters with that bow just the same.
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I kinda thought this and it's good to see you verify!!
Thanks!
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Had a very similar experience last week!
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I think mine was a sharp edge on the notch. I told my buddy about it, and he said “that’s what you get for stringing your bow every time you shoot!”
And I was just getting ready to set up a new string and have this older one for my backup… :banghead:
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OUCH!! That looks scary!
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WOW!! So much, I did not know!!! Thank you.
What do you mean by "too tight" on the bottom nock? I try to make my loops small, so they don't fall off, when the bow's unstrung....
That may be causing your wear issue right there using the small loops, but the shape may be an issue too. I've got a 3 part series video on tip overlays and shaping them correctly. In this clip it explains why you need a perfect tear drop shape to keep the string loop from moving while drawing the bow. A larger loop is very desirable for this reason. I know it makes stringing the bow a bit more challenging with larger loops. But its well worth the effort not having the string bind up in the tip notches and string wear too.... check this out. Kirk
https://youtu.be/hij4Vx1MP_4
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Thank you!... Will watch right now. :=)
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Are you loops a little to big and rubbing where the string nocks are cut around the belly side of the bow? Definitely a sharp spot somewhere.