Primitive Archer
Main Discussion Area => Bows => Topic started by: Josh Wilson on December 23, 2012, 10:53:19 pm
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I was discussing with two bowyers leaving the sapwood on the back on an osage longbow. One bowyer said in his experience that the sap wood was brittle and cracked, the other bowyer had had great results leaving the sap wood on. What are everyone else's experiences with this?
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I have no personal experience but I can say that I have seen plenty of excellent osage bows with sapwood on them.
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I've been told by an old osage bowyer that the sapwood is dead weight. And that the heartwood can do the tension and compression work, and then some.
One with sapwood and one without....still 2 different pieces of wood.
With probably 2 different designs and 2 different shooters.
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It depends on the stave and how it was cared for.
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Dead weight?, lol. If anything it is probably a bit less weight than the heartwood. I know it is just fine in tension. I have never made a sapwood bellied bow, so I can't attest to it's compression strength, ;). If there is any detriment, it might not have as high a recovery as heartwood, but that is just a guess on my part. The sapwood backed bows I have made have held there reflex just as well as heartwood bows.
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It depends on the stave and how it was cared for.
Can you elaborate on this?
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If the wood is cared for properly after harvest the sapwood can be used on the back. I have made osage bows that were all sapwood, just sapwood backing, 50/50 heart/sap and all heartwood. All made very good bows but the more sapwood the thicker the limbs will be.
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Sometimes staves of hedge will have portions of bark missing or knocked off by equipment etc.this exposed sapwood will check a lot and sometimes deeply if exposed to sun or too fast of drying.If I wanted to do a sapwood backed bow I would either use a stave that dried naturally with its' bark on intacked or remove the bark to a ring of sapwood and shellac or varnish the heck out of its' back and ends and dry it inside a shed out of the wind in the shade.Taking care of the stave.
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I agree. I think the osage sap wood is like whitewoods and deteriorates quickly. I know two people who tried and proudly proclaimed it was possible to use the sap wood. Both broke about a month later... I can't vouch for how it was treated though.
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I take off the sapwood on BL and osage unless there isn't enough heartwood. I've been doing this bow making thing for a long time. Someone always has a "revolutionary" idea that challenges accepted practices. If I made bows for a living I'd sure try to convince myself sapwood is as strong as heartwood, too, considering the extra work involved in ring chasing. LOL. IMHO caveat emptor. I sure would not buy an osage bow with sapwood on it no matter the need to leave it on. Now want me to tell you what I really think? :)Jawge
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I take off the sapwood on BL and osage unless there isn't enough heartwood. I've been doing this bow making thing for a long time. Someone always has a "revolutionary" idea that challenges accepted practices. If I made bows for a living I'd sure try to convince myself sapwood is as strong as heartwood, too, considering the extra work involved in ring chasing. LOL. IMHO caveat emptor. I sure would not buy an osage bow with sapwood on it no matter the need to leave it on. Now want me to tell you what I really think? :)Jawge
Heck, I've sold 3 sapwood backed osage bows, and never had one complaint, 8). George, I have boatloads of respect for you and your experience that dwarfs mine own and I sincerely mean that, so please don't take this the wrong way, but I have to disagree with your view on osage sapwood. I have made short heavier weight osage bows that have ended up chrysaling on the belly, which to me seems to takes a bit of work to do, and yet the sapwood has never failed on me.
I agree. I think the osage sap wood is like whitewoods and deteriorates quickly. I know two people who tried and proudly proclaimed it was possible to use the sap wood. Both broke about a month later... I can't vouch for how it was treated though.
White woods like hickory, hophornbeam, elm, etc? There's plenty of white woods that are excellent bow woods, and I don't think anyone finds the term word "white wood" a dirty wood. I will say that it will check very soon if you don't seal it as soon as you take the bark off. Larger staves as well as staves with knots are more likely to check as well. I split my osage almost always on the knots if I can, and split the staves out so that they are small enough not to check, but still have enough meat on them not to warp. I also slowly dry my staves inside my house. And if a stave is small enough and clean enough, sometimes I won't even seal the back, as it will most likely not check. But this is of course the exception, and usually pretty narrow staves, or scrap staves. I guess seasoning osage staves with the bark off and the sapwood on is not the easiest thing to do. But once the staves are seasoned, the sapwood has always worked for me when used as the back of a bow. Just throwing all that out there, ;D.
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Toomany, I might have not been specific enough... When I said deteriorates quickly I mean left to the elements. It's been my experience that whitewoods like elm, hickory and ash will start to deteriorate in a very short amount of time if left to the elements. With osage people don't generally worry about how long it's out in the elements...all fine and dandy until you try to use the sapwood, inmho.
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I think it works fine.
http://www.primitivearcher.com/smf/index.php/topic,26379.msg354408.html#msg354408
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toomanyknots, I know. It's ok to disagree about this. I thank you for the kind words. Jawge
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Ive only made one osage bow with the sapwood on and it worked out fine. Like others have said if the stave is well taken care of and is in good shape with no discoloration on the sapwood it will work. If theres enough heartwood theres really no reason to leave it on, just my opinion. The one I built with sapwood was from a limb without enough heartwood to make weight.
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Heres a link to the limbo I was referring to.
http://www.primitivearcher.com/smf/index.php/topic,36278.msg477374.html#msg477374
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I just went back to my TBB volume 1 and it describes the exact same failure that both of my friends bows suffered. Not saying it can't be done...but I personally wouldn't take the chance.
"I began to hear the tell tale tick from each new crack as it appeared on the sapwood back. The failures were both longitudinal and transverse failures that are unheard of in an all hardwood back. At any rate, one warm afternoon the bow suffered a violent death at full draw."
What the common denominator is, I don't know. Decay, design, variation in density, humidity??? I do know that all hardwood is pretty resilient to all the above.
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I've made a few sapling osage bows that were mostly sapwood or at least 50/50 and I'd put those bows against any bow I've made. It is all in how you handle the stave off the stump. Osage sapwood will cure out as strong as almost any whitewood if it is treated properly, just like any other bow wood. It is true, you can cut down an osage tree and let it lay for a long time and still get bow quality wood from it. You won't get any good sapwood from this tree but if you cut, split, seal and store properly you will have osage sapwood that will make a bow. Its not as strong as osage heartwood but it will make a good bow. Leaving a ring or two of sapwood on the back of the bow for the appearance is acceptable if the wood was properly cared for. IMO
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Josh my opinion is the sapwood doesnt have the same elastic strength the heartwood does. I have no way to be sure. Considering only the very outside, highest points do all the stretching and compressing, my guess is the heartwood bellies compression strength in much higher than the sapwoods elastic strength. Hence ticks and explosions. I have always used all heartwood and will contiunue because its just my gig.
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Here's what happens in all trees. Pardon the biology lesson but I'm a retired chem teacher who knows a little about biology and I just can't help it. Oh come on! Don't tune me out because I said biology LESSON from a teacher. Stay with me. :) First, the only living part of the tree is the cambium layer; we bowyers mistakenly call it the "inner bark". It's NOT bark at all. It contains the xylem and phloem which is the active transport system in the tree bringing the sap from the roots to the leaves. This is why girdling the tree will kill it. This is also why waiting for the sap to be "down" to cut makes no sense because we tear out all that xylem and phloem stuff along with the sap anyway.
Second, all sapwood eventually turns into the DENSER, STRONGER heartwood. Therefore, the closer to the heartwood is your sapwood back of the bow the stronger it will be. That is why we've all had so much success with osage and BL saplings where the sapwood is closer to the heartwood automatically. It is also not as old as big tree sapwood so it is much "fresher". I like that term. Someone used it previously. Fresher sounds so nice. Sapling sapwood is ....fresher. Thank you.
In conclusion, if you've taken big tree sapwood and left it for the back of the bow because it looks pretty and simulates yew then congratulations. I'm not willing to take the chance and fly in the face of science.
Please feel free to discuss this with me.
Jawge
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In conclusion, if you've taken big tree sapwood and left it for the back of the bow because it looks pretty and simulates yew then congratulations. I'm not willing to take the chance and fly in the face of science.
Please feel free to discuss this with me.
I'll give it a go. With that argument, it sounds like you have a bias towards sapwood in general, when we all know that there are many many trees that will make excellent bows with the first ring as the back, with really only a minority that won't, like cedar or willow I guess, and even then I have seen unbacked bows of both on here and paleoplanet? It seems logical to me that the strongest part of the tree in tension generally would have to be the sapwood, if the tree is to survive strong winds and storms swaying the trees and branches back and forth. The part of the tree under the most tension would have to be the outer sapwood. In my opinion the heartwood of osage has been used by itself for so long, combined with the sapwood's tendency to check when seasoning, that people just started thinking it was unusable.
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He doesn't sound bias at all. Ppl have been taking the sapwood of osage for 1000's of years and for good reason.
Yes lots of trees make good bows with the first ring under the bark. And osage does. But it does not provide any performance gain other than osage bowyers wanting there bows to resemble our yew bows >:D
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No bias, toomanyknots, against sapwood. My remarks were intended for BL and osage. Whitewood sapwood is gold. Sorry I did not make that clear. Your opinion is noted and considered. On osage and BL sapwood rings are so few that the heartwood rings are still pretty close to the bark and you are making a good case for choosing the first few heartwood rings as the back of the bow especially when you consider how much denser the heartwood is than the sapwood. Jawge
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No bias, toomanyknots, against sapwood. My remarks were intended for BL and osage. Whitewood sapwood is gold. Sorry I did not make that clear.
Sorry for misunderstanding you. Just trying to point as many holes in an argument as I can I guess, >:D. I honestly don't know anything about black locust. The only thing I do know is that all I have ever cut has been ridden with big wood eattin grubs. In the couple spots I did know of, there were so many perfect diameter perfectly straight black locust trees it was insane, but the bug infestation was so bad that you could see two or 3 big old bug holes on the outside of almost every tree without even taking the bark off. I did find a new spot with some black locust in a whole different woods though. I think that they might be clean, as I have cut many other trees very close and have never found any bug damage, but who knows. I think I will cut a couple next spring and find out. Black locust is an entirely different creature for me, but I have always wanted to try some and see what made the cherokee like it so much.
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I like BL, toomanyknots. It has been awhile since I made one. At 64 years I decided to go back to my roots and started working a BL stave. Then I pinched a nerve in my back so the BL project is on hold. The past few years I'm seeing BL trees with worm holes in them too. But last year a storm downed some clean stuff for me. I'm getting there. A little better each day. Lord willing I'll be working some soon. Just be careful with those sapwood backs you like. :) Jawge