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how to fill checks in yew

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freke:
Hi
I working on yew bow with bamboo backing (not applied at this point), the wood is really poor quality so I have no big hopes but see it as a learning project, One limb has a year ring that check badly, I have seen it coming and after heat correction it has increase, or at least been more visible.

The layout of the bow is a flatbow 40 mm parallel 2/3 wide and 67-68"ntn, and I am not experienced enough with yew-boo to see how thick limbs needs to be to get a bow out of the stave but I hope the majority of this check will be gone during tilering although I am afraid I need to seal it some way if it goes too deep. I have only one successful yew-boo built before.

My question, is there any good method to fil it or at least stabilize?  It goes over two third off one limb starting in handle on one side, the other side is not as bad. Before II put some heat on the bow it was more a clearly visible hair line, but now is it easy to feel with the nail and too big to fill with cyanacrylat.

Thanks
Jonas

Hamish:
Finish all heat treating, and corrections before gluing, as superglue will vaporise when heated.

I would use superglue, because epoxy won't get deep down into the cracks. You might also be able to clamp the sides to help close up the gap.

freke:

--- Quote from: Hamish on August 14, 2022, 08:18:53 am ---Finish all heat treating, and corrections before gluing, as superglue will vaporize when heated.

I would use superglue, because epoxy won't get deep down into the cracks. You might also be able to clamp the sides to help close up the gap.

--- End quote ---

I will do all corrections and heat-treating and applying the Boo before I seal the crack anyhow hoping to be able to remove the worst part of the crack, super glue is handy and probably what I will use if nothing better comes up.


I have heard that there should be methods of apply epoxy deep in cavities but not find any easy way doing it?

Hamish:

Even a runny type of epoxy is still very viscous compared with superglue.

You can sometimes run epoxy through a crack that goes through the belly out through the back. You set a vacuum cleaner hose on the back side and suck through the crack. It works in some cases.

Most of the time when you apply epoxy into your type of crack it only gets in to the first couple of mm. This gets removed during tillering and exposes the crack again.

I would heat treat, then glue the crack, and clamp it. It may totally close up. Then you can back it. Other wise if the backing is already on, it probababy won't close up.

You can always do a dry run and clamp it without glue to see how much it closes up.

freke:
 right, it don't hurt try before backing  I will see if it can be done by clambs or bend the stave so it closing gap more and use super glue - it would at least close the bottom  that  worries be most if it start grewing.

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