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Author Topic: Cracked bow limb?  (Read 1850 times)

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Offline Rubert123

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Cracked bow limb?
« on: March 30, 2020, 10:32:29 am »
Hello everyone,

I don't have much experience making bows, but I am working on my first yew bow, and now that I finally got my hands on such a piece of wood I was very sad to see that a crack appeared in one of the limbs as I tried to flip them.

I love to hear some advice from you guys if I am suposed to start over of fix this somehow.

Ruben
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Offline airkah

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Re: Cracked bow limb?
« Reply #1 on: March 30, 2020, 10:39:57 am »
Its a little hard to tell from the picture, but this is from when you flipped the tips? If so, I would fill it with super glue and end up wrapping it
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Offline Pat B

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Re: Cracked bow limb?
« Reply #2 on: March 30, 2020, 10:41:36 am »
I would fill those cracks with super glue and continue on. Be sure the super glue goes all the way down in the cracks. Looks like you have enough thickness there so the cracks may disappear as you reduce the tips. If not you can add a thin piece of wood that follows the curve then reduce it to size, but we can discuss that later if necessary.
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Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline PEARL DRUMS

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Re: Cracked bow limb?
« Reply #3 on: March 30, 2020, 10:46:29 am »
You don't need to wrap them as they are tension related from heat bending. The wraps wont do anything but add weight out there and give you one more thing to work and/or sand around as you go. My most favoritest bow in the whole world has a few of those on the upper limb. Its been shot thousands and thousands of times. 
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Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.

Offline bjrogg

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Re: Cracked bow limb?
« Reply #4 on: March 30, 2020, 10:54:27 am »
Yup no worries it’s on compression side and in a non working area. Just fill with thin super glue.

In future when you bend your recurve tips. If you can put a thin strip of metal over belly side of curve it would help to prevent those grains from lifting. I can’t post pictures now but maybe someone can

Bjrogg
« Last Edit: March 30, 2020, 11:18:06 am by bjrogg »
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Offline Pat B

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Re: Cracked bow limb?
« Reply #5 on: March 30, 2020, 10:56:58 am »
Pearlie, that what happened to the bow I gave you, hence the underlays.
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Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline Rubert123

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Re: Cracked bow limb?
« Reply #6 on: March 30, 2020, 11:42:50 am »
Thanks for the replies!

I have now filled it with super glue, and wrapped it with tinfoil in order to protect that part when I start heat bending again.

And yes those cracks apeared after flipping the tips.

As you can see on my pictures, ons side is flipper more because I stopped after hearing a crack.
Is it a good plan to go back to branding after this?

Thanks again everyone
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Offline DC

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Re: Cracked bow limb?
« Reply #7 on: March 30, 2020, 11:44:59 am »
How are you heating it and what are you bending it on?
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Offline PEARL DRUMS

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Re: Cracked bow limb?
« Reply #8 on: March 30, 2020, 11:46:00 am »
Don't get near that glue with heat. It will emit very caustic vapors when warmed up.
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Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.

Offline Rubert123

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Re: Cracked bow limb?
« Reply #9 on: March 30, 2020, 11:55:29 am »
Im using the heat gun method and im bending it over a wooden block that I sawed into shape.
slowly pushing it down, wiping it with oil to not scorch the wood.

I am aware of the glue and heat, I hope the tinfoil will keep most of the heat out, and with the heatgun I should be able to focus the heat away from that part.

Also the cracks that I have now glued, do not seem to major on my pictures, but you can feel them sticking out when touching the wood.
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Offline paulc

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Re: Cracked bow limb?
« Reply #10 on: March 30, 2020, 12:03:15 pm »
I've only flipped tips twice now so take my opinion with a large dose of salt, and had those same cracks show up each time.  Hickory and hackberry bows.  Both times the cracks have sanded out as I continued finishing the bow.  With my limited experience I would be real hesitant to add more bend without some more assurance the cracks won't go deeper.  I would say the tin foil has to go otherwise the wood beneath will be different temp than rest screwing up your efforts to flip the tip. 

Remove more wood, rub in some oil, add more heat very slowly and bend very slowly...? 

FWIW....Paul
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Offline PatM

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Re: Cracked bow limb?
« Reply #11 on: March 30, 2020, 12:15:54 pm »
You should have steamed or boiled.   Certainly if you want to try again you'll have to do either of those rather than dry heat.

 It is quite easy to scrape the cracks out and add overlays that replace the damage.  Plus it can look nice if done well.
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Offline DC

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Re: Cracked bow limb?
« Reply #12 on: March 30, 2020, 12:34:41 pm »
Quote from: PatM on March 30, 2020, 12:15:54 pm
You should have steamed or boiled.   Certainly if you want to try again you'll have to do either of those rather than dry heat.

 It is quite easy to scrape the cracks out and add overlays that replace the damage.  Plus it can look nice if done well.

+1  If you try to bend it more the crack will probably get worse. I would be tempted to undo the other limb to match.
 The caul you bend it over has to have a very smooth even bend. A small unevenness concentrates the strain into one spot. A small lump or knot on the back of the recurve will do the same thing. Steam or boiling is the way to go. Yew is like pasta. Boil it and it will bend :D
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Offline Rubert123

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Re: Cracked bow limb?
« Reply #13 on: March 30, 2020, 01:52:54 pm »
I made the bow from this small yew log, It had been left for pretty long, (maybe 3 years) the ends started splitting already.

I was curious if leaving the wood drying that long could be the cause of the cracks in my bow.
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Offline DC

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Re: Cracked bow limb?
« Reply #14 on: March 30, 2020, 03:23:16 pm »
I don't think so. There is a bit of a learning curve to bending wood. You'll just have to keep at it until you figure it out. I would suspect that you were pushing too hard for the amount of heat you had in it but that's shear speculation on my part. The weight of the bow is usually enough to bend it. If you must us dry heat, hook/ clamp the tip to the caul with the bow at about a 45° angle and heat it slowly and thoroughly starting at the tip. Hold the gun 4" or so from the wood, no closer. When it's warm enough the bow will start to drop without any help. Then move the heat gun a little further down. Gentle nudges are all that's needed.

https://www.youtube.com/watch?v=2GerQcfYrGo

You can see that Jamie hung a rasp on the end.
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