Author Topic: Issues with Yew sapwood  (Read 2011 times)

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Offline Tanneur

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Issues with Yew sapwood
« on: June 29, 2016, 11:53:03 am »
Hi!

I recently worked with yew staves (taxus baccata) that have longish holes in the sapwood. I don‘t now were they come from. Have never seen this before. There are no branches in the holes and they are not round but longish. Anyone of you experienced guys working with yew have a clue what that might be and if it could cause troubles later on?

Here are how they look like:

One larger and one smaller longish hole. There is some black „stuff“ in it that comes out when cleaning but the inner and outer edge seems to be strong.



Look of the longish hole with bark removed. There is a longish black center and some cambium in the hole.



One larger longish hole, opened up. Once more, there was no branch coming from the hole.


Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Re: Issues with Yew sapwood
« Reply #1 on: June 29, 2016, 12:17:00 pm »
Probably a knot that has almost grown over.
I would try to excavate to see if there is a cavity of black manky stuff beneath it. But try not to cut into the sapwood, an 1/8" drill in a hand drill or a ground down needle file is good for picking it out.
It doesn't matter too much in terms of the integrity of the back, but what you want to avoid is a cavity that goes deep into the compression side which will collapse and cause a pinch on the belly. Is there any sign of a corresponding pin knot on the belly.
Hopefully it will only go as deep as the sapwood in which case, fill it with what ever takes your fancy, just to keep any moisture or rot out of it. Filling won't strengthen the back.
If you are really worried by it you could rasp out a long shallow scoop say 3" long down to half/threequarters the depth of the sapwood and clean it out, fill it and put a matching sapwood patch over it, but I don't think it's necessary.
They are just nice character features... if you did patch, you could patch over the little cluster of pins with the same patch.
What draw weight is the bow going to be?
Del
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Offline Tanneur

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Re: Issues with Yew sapwood
« Reply #2 on: June 29, 2016, 12:35:41 pm »
Del thanks. Yes, there are pin knots on the belly but impossible to say which one belongs to which hole. I dug into some of the holes until clear wood was visible, maybe 1/6 to 1/5“ deep. The holes are very narrow though. I like the idea that the sapwood was about to close the holes. But why are those holes elongated and not just round and not a single branch in any of them?

As for poundage, I don’t know. The heartwood is superb.

Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Re: Issues with Yew sapwood
« Reply #3 on: June 29, 2016, 12:50:31 pm »
I dunno, maybe it was a bud or shoot that got killed by frost. It prob was round once upon a time but the sapwood has slowly closed in from either side...
I dunno, you need to go back in time and set up a time lapse video over the last 15-20 years  >:D
Del
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Offline DC

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Re: Issues with Yew sapwood
« Reply #4 on: June 29, 2016, 12:58:01 pm »
On Pacific Yew we get animal scratches and such that leave marks like that. They are usually bigger though. Bears don't make small scratches. Woodpeckers might do that. Another limb falling against it, just about anything.

Offline JoJoDapyro

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Re: Issues with Yew sapwood
« Reply #5 on: June 29, 2016, 06:16:40 pm »
Del thanks. Yes, there are pin knots on the belly but impossible to say which one belongs to which hole. I dug into some of the holes until clear wood was visible, maybe 1/6 to 1/5“ deep. The holes are very narrow though. I like the idea that the sapwood was about to close the holes. But why are those holes elongated and not just round and not a single branch in any of them?

As for poundage, I don’t know. The heartwood is superb.

The small branch grew up, not straight out.
If you always do what you always did you'll always get what you always got.
27 inch draw, right handed. Bow building and Knapping.

Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Re: Issues with Yew sapwood
« Reply #6 on: June 30, 2016, 01:57:34 am »
Del thanks. Yes, there are pin knots on the belly but impossible to say which one belongs to which hole. I dug into some of the holes until clear wood was visible, maybe 1/6 to 1/5“ deep. The holes are very narrow though. I like the idea that the sapwood was about to close the holes. But why are those holes elongated and not just round and not a single branch in any of them?

As for poundage, I don’t know. The heartwood is superb.

The small branch grew up, not straight out.
Good call, you get a lot of those little shoots that grow up alongside the trunk.
Del
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