Primitive Archer
Main Discussion Area => Bows => Topic started by: doggonemess on July 30, 2012, 04:19:53 pm
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Greetings,
I have a yew stave that I'm working into a longbow and I've run in to something I'm not sure about. It looks like this limb must have picked up some mold under the bark, but it did not get through the sapwood (I scraped some off and checked). It seems to have discolored the sapwood that green / blue color in the images below. Is there any reason I should worry about this? It is fairly widespread, so I can't work around it like a knot.
I'm not too worried, but wanted to know if anyone had seen this before. Personally, I think it will add a cool bit of character to the bow if it makes it through finishing. 8)
One view of it:
(http://thatsmywebguy.com/hosted/images/photos/archery/yew_stave%20(6)%20(Custom).jpg)
Again, with the flash:
(http://thatsmywebguy.com/hosted/images/photos/archery/yew_stave%20(4)%20(Custom).jpg)
Longways:
(http://thatsmywebguy.com/hosted/images/photos/archery/yew_stave%20(3)%20(Custom).jpg)
Below is where I scraped it down to the heartwood to check inside. It was damaged in this portion anyway, so I figured I'd dig in and see what I could find. The tiny hole is from my moisture meter, not insects.
(http://thatsmywebguy.com/hosted/images/photos/archery/yew_stave%20(7)%20(Custom).jpg)
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Yew is really resistant to decomposition, similar to cedar due to its resin. I started a yew flat bow the other day with messed up sapwood and Iam now in the final tiller process and I haven't had any problem with it. And on mine the sapwood is black in some " not so choice" places.
So I think you'll be alright.
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To me that looks like spalting which is caused by fungus. I would be worried about tension failure in wood that had that type of coloration. Not saying it can't work, but I think its likely to be compromised.
Gabe
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Blue stain happens when soft wood isn't dried quickly enough after harvesting or if it is in contact with the ground too long before being processed. It is bacteria (first process of decay ) that has died when the wood dried out and it didn't have enough moisture to survive any longer. It turns blue when dead. Very common in lower grade White Pine.Doesn't seem to affect the structure of the Pine ,but I've never made a bow out of it either. Giv'r a try. What's the worst that could happen. ..........(wear safety glasses and a helmet ,just in case.)
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I agree; that looks like some form of decay by bacteria (or possibly fungi). I'm sure it won't make the wood any stronger, but I doubt it'll break on you because of that. I'm actually quite surprised to see such a discoloration in yew. It's pretty rare, because the wood is so resistant to decay. Had the log been laying on the forest floor for a while? Or in a damp cellar for a few weeks? You don't need to quick dry yew, but it's important to not leave it in a too damp environment after cutting. This account for all woods, though.
I think you should be fine, as long as you keep the drawweight moderate.
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I'm actually quite surprised to see such a discoloration in yew. It's pretty rare, because the wood is so resistant to decay. Had the log been laying on the forest floor for a while?
Yep. ;D
It's actually funny, before I knew that the tree was yew, I cut off a branch that was hanging into my other tree and chucked the whole thing in the backyard. A year later, I realized what a stupid thing I did, and went back and looked for it.
I didn't find it then, but a few months later, I was looking for a lost arrow and lo and behold, there is the yew limb, buried under piles of dead leaves, rotting pine, and grass clippings. It spent almost two years under that crud and only the bark was moldy in a few places. Amazing stuff.
I was totally doing a victory dance when I found it. I figured there was no way it would be in any condition that would make a bow, but just scraping the bark off revealed perfectly seasoned wood. Woohoo!
I'm still working it down, I think it's going to be an awesome bow.
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IF (not saying you will) you notice the sapwood is crumbly, stinks of fungus, or is noticeably weaker/softer in the stained areas, you'd beter think things over. I think you should be able to tell the difference if the sapwood is not as strong as it used to be. In that case, just remove as the sapwood and follow the heartwood :) Unbacked 100% heartwood yew bows have been made, but a backing of sinew or rawhide would be safer.
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Fungus can substantially weaken the wood, but it can just as well leave its stability intact. There is a procedure to treat spruce with Schizophyllum commune to make it lighter without loosing stability. This has been used in violin building. Sometimes I also find hazel shoots that have been lying outside for a couple of month to be still hard, but much lighter that those cut fresh (compared once both are dry, of course). These make very light and stable arrow shafts, a bit thick to the eye, though.
So this could be ok, or really bad.
Good luck with this piece. You really can't tell yet, I think.
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Fungus can substantially weaken the wood, but it can just as well leave its stability intact. There is a procedure to treat spruce with Schizophyllum commune to make it lighter without loosing stability. This has been used in violin building. Sometimes I also find hazel shoots that have been lying outside for a couple of month to be still hard, but much lighter that those cut fresh (compared once both are dry, of course).
Thanks for that little bit of knowledge, very cool!
Yeah, I'm going to make the bow and then we'll see how it works. Worst case, it breaks and I've gained a lot of bow making experience with yew. Best case, it works, and I've got an awesome longbow!
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Final update for this stave - it broke. :(
It seems that there was a problem with the sapwood about a foot from the tip of one end. It split there, and I decided to work on retillering it into a short bow. When I was exercising the wood after tillering, it broke again, this time in a much more spectacular fashion. I took some pics, I'll upload them later.
I'm disappointed, but this was a great learning experience. I now have worked yew all the way through the tillering process, and I'll be able to take what I've learned and transfer it to the next stave. This one wasn't a great piece of wood anyway - mold, pins, knots, etc. It would have been cool to make it work, though!
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thats too bad man. :(