Author Topic: Small chrysal in bow: expectations?  (Read 1863 times)

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Offline Jon_W

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Small chrysal in bow: expectations?
« on: July 17, 2021, 12:17:14 pm »
So I have been shooting my new bow frequently and noticed a chrysal forming on the belly next to a knot. I've probably shot 200 arrows before seeing this. Can anyone tell me the specifics of why these form, what I may have done wrong, and what my expectations for the bow should be? Can I still shoot it? Will it eventually snap at that place? I tried to overbuild the bow so I am wondering if the character got in the way of seeing a weak point in the tiller. Thanks everyone!
"So long as the new moon returns in heaven a bent, beautiful bow, so long will the fascination of archery keep hold in the hearts of men"   ~ Maurice Thompson

Offline Del the cat

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Re: Small chrysal in bow: expectations?
« Reply #1 on: July 17, 2021, 12:32:59 pm »
IMO it is a "pinch" due to the knot compressing, pick out the knot and plug it. Hopefully it won't get worse.
If you leave it, it will probably get worse. Even if that's not the cause, plugging it will reinforce that area.
A knot may be solid, but is often surrounded by black manky bark which has zero compressive strength, the bark will collapse stressing the surrounding wood.
If the knot is an actual hole, that has zero compressive strength too... maybe replace it with a hole from some Osage... they are much stronger ;)
Del
« Last Edit: July 17, 2021, 12:36:20 pm by Del the cat »
Health warning, these posts may contain traces of nut.

Offline bassman211

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Re: Small chrysal in bow: expectations?
« Reply #2 on: July 17, 2021, 12:53:14 pm »
My fix would be to plug the hole ,and wrap it.

bownarra

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Re: Small chrysal in bow: expectations?
« Reply #3 on: July 18, 2021, 02:17:11 am »
The problem was that you didn't compensate for the width the knot is taking up. you should add the width of the knot to the 'normal' width your taper would dictate through that spot.
so you have 'not enough' wood (other than the knot) and that wood is already compromised by the knot. the wood arounmd the knot will also have funky grain. Funky grain also lowers the woods ability to handle compression (compared to nice straight grain)....
So all these things have combined to cause excessive compression where your chrysal is. A chrysal is the fibers of the wood fracturing and then basically one side will ride up and over the ends of the fibers on the other side. The fibers have been compressed past heir elastic limit and have ruptured.
If you were to leave it and continue shooting it will get worse.
If you wrap it unfortunately it will also get worse.
Plugging the knot doesn't fix your problem now. Plugs can be a good idea but you must do it before bending the bow too much.
As I said above the way to avoid it is to make the bow appropriately wider around the knot. Not thicker like I see recommended sometimes - thicker will INCREASE the strain there not lower it.
Unfortunately a chrysal cannot be fixed satisfactorily. There are temperary 'fixes' but other than learning how temparary they actually are the best fix is to start again.
Chalk it up to experience.

Offline SLIMBOB

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Re: Small chrysal in bow: expectations?
« Reply #4 on: July 18, 2021, 10:53:07 am »
+1 bownarra.  You have less wood doing the work, than is required...unless you went thicker to compensate, and then likely you just made it worse.
Liberty, In God We Trust, E Pluribus Unum.  Distinctly American Values.

Offline George Tsoukalas

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Re: Small chrysal in bow: expectations?
« Reply #5 on: July 18, 2021, 05:48:31 pm »
In essence the bow is bending too much in that area.You could retiller leaving that area alone and retiller the other limb to match.

Excellent post, Bownarra. To add...when tillering leave the knotted area so that it does not bend as much as the rest of the limb...just slightly flatter than the rest of the limb.

Eventually, the bow will fold up like a book if left as is.

Jawge



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If you ain't breakin' you ain't makin!

Offline rps3

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Re: Small chrysal in bow: expectations?
« Reply #6 on: July 18, 2021, 09:33:11 pm »
Keep shooting it and let us know how long it lasts. I think most people become irritated looking at their chrysalled bow and never shoot it enough after that to see how many shots are left in it. Don't ask me how I know that.  ;D

Offline bassman211

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Re: Small chrysal in bow: expectations?
« Reply #7 on: July 19, 2021, 08:38:52 pm »
I would shoot it till it started to hinge.

Offline Digital Caveman

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Re: Small chrysal in bow: expectations?
« Reply #8 on: July 20, 2021, 09:57:03 am »
Keep shooting it and let us know how long it lasts. I think most people become irritated looking at their chrysalled bow and never shoot it enough after that to see how many shots are left in it. Don't ask me how I know that.  ;D

I kind of agree.  I also think that once it starts to hinge it will be much harder to fix.  (I've chrysalled a lot of bows.   :D)
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Offline Selfbowman

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Re: Small chrysal in bow: expectations?
« Reply #9 on: July 21, 2021, 02:51:35 pm »
Bownara said it correctly as far as I’m concerned. Arvin
Well I'll say!!  Osage is king!!

Offline Tim P

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Re: Small chrysal in bow: expectations?
« Reply #10 on: July 22, 2021, 02:54:03 pm »
The problem was that you didn't compensate for the width the knot is taking up. you should add the width of the knot to the 'normal' width your taper would dictate through that spot.
so you have 'not enough' wood (other than the knot) and that wood is already compromised by the knot. the wood arounmd the knot will also have funky grain. Funky grain also lowers the woods ability to handle compression (compared to nice straight grain)....
So all these things have combined to cause excessive compression where your chrysal is. A chrysal is the fibers of the wood fracturing and then basically one side will ride up and over the ends of the fibers on the other side. The fibers have been compressed past heir elastic limit and have ruptured.
If you were to leave it and continue shooting it will get worse.
If you wrap it unfortunately it will also get worse.
Plugging the knot doesn't fix your problem now. Plugs can be a good idea but you must do it before bending the bow too much.
As I said above the way to avoid it is to make the bow appropriately wider around the knot. Not thicker like I see recommended sometimes - thicker will INCREASE the strain there not lower it.
Unfortunately a chrysal cannot be fixed satisfactorily. There are temperary 'fixes' but other than learning how temparary they actually are the best fix is to start again.
Chalk it up to experience.

What about making the limb thinner above the knot (similar as how one would normally leave the limb wider at the knot) and then retillering it?
of course the bow would come out lighter. Has anybody tried this? might be a way to give the bow a second life.

I 'm a rookie myself. So don't take my word for it. I was just wondering if this might be an option.

Tim