Author Topic: Repair or leave?  (Read 3279 times)

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Offline Kidder

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Repair or leave?
« on: June 19, 2021, 04:20:56 pm »
So I’m just finishing an BBO. It’s a relatively low stress design - 66 TTT, 1 inch Perry reflex post shooting in. And I’ve got a pretty short draw - 25 inches or so. It has a tiny pin knot on the side the runs to the back under the boo. Upon putting a couple coats of finish on it I’ve noticed there is a small fret right above the knot. It’s located on the bottom limb about 3 inches above the middle boo node. Everything else looks fine. Is this something to try to fix or just leave it?

Offline Pat B

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Re: Repair or leave?
« Reply #1 on: June 19, 2021, 05:39:28 pm »
The tiller looks very good. You could put a wrap over the pin and one on the opposite limb for symmetry. If nothing else might give you a little security. A drop of super glue in the check too.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline Digital Caveman

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Re: Repair or leave?
« Reply #2 on: June 19, 2021, 05:48:41 pm »
I had a similar issue on the plains bow, and I thought about a sinew wrap, but figured that would be hiding something and so decided to adjust the tiller, and now it is too light.   :-\

Yours will probably be fine though, I have one bow that fretted by a grain wrinkle, but it never got worse.  I think frets due to bad tiller are much more serious.
God Bless America

Offline stuckinthemud

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Re: Repair or leave?
« Reply #3 on: June 19, 2021, 06:05:48 pm »
drop of superglue and take a photo or some measurements to monitor it

Offline Dances with squirrels

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Re: Repair or leave?
« Reply #4 on: June 19, 2021, 06:26:29 pm »
I doubt superglue will do much for it. It can't fix what's already crushed and can't get into the wood that isn't crushed yet. That and the wrap thing are just 'feel good fixes', imo. I'd shoot it and see what happened. If it got any worse and I really wanted to try to save it, I'd do a half round patch like Dean Torges advocated. I've had good success with them.

http://www.bowyersedge.com/patch.html
Straight wood may make a better bow, but crooked wood makes a better bowyer

Offline Eric Krewson

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Re: Repair or leave?
« Reply #5 on: June 19, 2021, 11:57:01 pm »
A half round patch won't hold up in the long run, I tried several of them, they always turned loose, it might be a months or several years but they do turn loose.

I would ignore the small fret, the bamboo will hold your bow together. I would remove the finish and superglue it, marvelous stuff.

This patch lasted three years, I replaced it and it only lasted a few weeks.


« Last Edit: June 20, 2021, 12:00:54 am by Eric Krewson »

Offline Kidder

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Re: Repair or leave?
« Reply #6 on: June 20, 2021, 12:35:53 am »
Thanks for all the replies. I’m just going to CA it and call it good. Bows could stop breaking my heart anytime now...

bownarra

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Re: Repair or leave?
« Reply #7 on: June 20, 2021, 03:10:23 am »
Superglue won't do anything. Patches are very difficult to get right(your patch is too small Eric, the problem is the mating edges are at too sharp an angle). Wrapping the limb does nothing.
The problem is the pin knot. Nature put it there and that's it. Not much you can do now.
To avoid issues like this you must use super clean belly wood. Learning how to judge belly wood that has 'issues' is a real fine skill. Personally now I only use the very best materials on lam bows, after seeing pin knots fail too many times.

Online Hamish

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Re: Repair or leave?
« Reply #8 on: June 20, 2021, 05:11:31 am »
The English approach to fret repair seems more effective than the Torges "scoop" patch.  They use a much longer piece, and rasp out the fret, with a much more gentle transition, more surface area for the glue, so the ends are much less likely to lift. Still have to use top glue like urac etc. Del probably has a video tutorial or blog for it. Chime in please Del?

No surprise,the best cure for a pin knot is always to compensate for it, from the layout, through to tillering.

Offline H Rhodes

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Re: Repair or leave?
« Reply #9 on: June 20, 2021, 08:47:58 am »
Osage is tough stuff.  Backed with bamboo, your fine tiller and a conservative design like you have there - I say shoot it a couple thousand times and see what happens.  I wouldn’t worry over that spot unless it causes a problem at some point.
Howard
Gautier, Mississippi

Offline Eric Krewson

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Re: Repair or leave?
« Reply #10 on: June 20, 2021, 09:11:27 am »
Bownarra, have you read Dean Torges's writings or just offering an opinion? He recommended making the patch a little undersized and leaving an excess amount of glue in under the patch, I followed his directions to a T.

Tell me about all the similar patches you have tried and what the outcome was.

Like I said before, If I haven't done it I don't say a word when a question comes up. I think the guys who ask a question deserve an answer from someone with actual experience, not opinions.

I have to agree with the tillering on that bow, spot on. As for superglue, you are right if the crack is microscopic, the glue won't wick in. One property of super glue is soaks in the surrounding area a hardens it, like case hardening making it less likely the crack will spread.

For maximum wicking I used to keep a bottle of the thinnest Zap-A-Gap superglue on hand, it is thinner than water and soaks right in.

The last time I posted that property on a muzzle loader form about crack fixing I got the horse laugh from the so called experts like we see here sometimes.

One of my critics went so far as to call the company that made a particular brand of super glue and ask a tech rep about what I had posted. Surprise, surprise, the tech rep told him "yes, that is a property of our glue that we have never emphasized".

I didn't read about this superglue property, I found it out from fixing cracks in bows and flintlock rifle stocks.

If any of you have used superglue and sawdust as a filler/patch you will see the chemical reaction between the two, lots of heat and even smoke, the superglue is changing the composition of the wood.

Here is an example, not bow related but it is wood; I bought a M/L kit (Kibler SMR) at a bargain price, when I got the kit I found the previous owner had neglected to mention there was 2 1/2"crack in the forestock. Apparently he didn't know how to remove the barrel and had yanked it out cracking the stock.

The wood was very thin at the crack, I superglued the crack and held it closed with my fingers until the glue set, I knew this probably wouldn't hold so I went inside the barrel channel and soaked all the wood in a 1 1/2" circle around the crack with as much superglue as the wood would suck up. After the glue set the wood was so hard a chisel wouldn't cut it. This crack will never turn loose.

The crack is above the pin angled down to the left, fixed properly it is hard to see.

« Last Edit: June 20, 2021, 09:54:32 am by Eric Krewson »

Offline SLIMBOB

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Re: Repair or leave?
« Reply #11 on: June 20, 2021, 10:09:26 am »
I have looked at the pic of your bow since you first posted it looking for the fret.  I have never had one on an Osage bow, pins or no pins, though I have had them on white woods.  Granted, yours is a lam bow and that changes things I suppose.  None-the-less, I have noticed in blowing up the pic and scrutinizing it, that the bow appears to get marginally more narrow at that spot.  It could be just an optical illusion in the pic.  Have you checked it with a set of calipers?  If I am wrong, just disregard, but if it is more narrow right there it could influence which way you should go with it.
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Offline Eric Krewson

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Re: Repair or leave?
« Reply #12 on: June 20, 2021, 10:22:40 am »
Another thing; After I posted the above crack fix one of the "experts" decided I needed a scolding for using superglue to fix a crack. He said superglue would oxidize in a wood repair, turn white and turn loose after 5 or more years.

I don't know what planet he comes from, these guys never miss an opportunity to give someone like me a scolding for the error in my ways.

Turns white and oxidizes, horse hockey;

Here is one of my early bows, one of those "I will make a bow out of this tortured stave just to see if I can" bows. It has 13 superglue filled drying checks down the back, plenty of shooting and none of the cracks ever oxidized or turned loose. Now that the bow has turned dark you can't even see them. I made the bow in the 90s but reworked it in 2002 to have my typical narrow tips and gave it a gizmo tillering. Turns out this wood is one of the top pieces I ever made a bow out of, the cast is incredible and it never took any string follow at all. I made it before I started reflexed bows with heat during the tillering process.

Being an old dude, I only shoot 45@25 now so this bow is relegated to the "wall art" category.

« Last Edit: June 20, 2021, 10:37:24 am by Eric Krewson »

Offline JW_Halverson

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Re: Repair or leave?
« Reply #13 on: June 20, 2021, 11:47:00 am »
Oxidize and turn white? Huh? Cured cyanoacrylic is chemically inert, it takes a pretty serious agent to even get it to debond and even then requires lots of surface contact along with time. If you wanted to undo that crack in the rifle stock you would need to submerge it in acetone for weeks and weeks!  Some poor ML guys are just desperate to be known as "hysterically correct" and cannot help but run their mouths on 21st century media about how they are 18th-century transplants!  LOL

The super-thin stuff is designed to wick into tiny spaces, and what is wood? Nothing but a pile of lignin absolutely full of tiny spaces!  I'd also recommend using the thin stuff to soak into the cracks. Zap-A-Gap has been around a very long time and is a high quality product.
Guns have triggers. Bicycles have wheels. Trees and bows have wooden limbs.

Offline Dances with squirrels

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Re: Repair or leave?
« Reply #14 on: June 20, 2021, 03:44:10 pm »
My patches are holding up fine, Eric. I don't advocate something unless I've done it myself either. Sorry, but you didn't follow Dean's instructions to a T, I can tell just by looking at your patch. Also, he didn't recommend leaving the patch undersized, or with an excess of glue under the patch. Dean would correct you himself if he were here. Revisit the article, then we can discuss further if you like.
Straight wood may make a better bow, but crooked wood makes a better bowyer