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Main Boards => The Bowyer's Bench => Topic started by: b.glass on April 01, 2010, 11:58:00 AM
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I was working on some kids bows yesterday afternoon and decided to take a break and work on my eastern red cedar stave.
Well I couldn't seem to put it down and I'm near the backing issue. I had been thinking rawhide all along but since looking through one of the Bowyers Bibles, I have been contimplating sinew.
I also have some knot issues I'm not sure how to handle. I have rawhide backed a board bow a few years ago and have never sinew backed.
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How long is the bow you are working on ? if shorter I would use sinew
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i agree with silent bear, if its short then sinew will help a bit. as far as knots it depends on the type, usually just leave extra wood around them and scrape outward around them in all directions to form a moundlike section to help keep them strong. if theyre knots that have holes then fill them with either superglue or i use homemade wood putty made with tb3 and sawdust. just be sure to pack the putty in tight and make sure you put a little glue inside the knot first to ensure good gluing, since tb3 shrinks as it dries. pics would help to see what kinda knots youre dealing with.
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Mona,
I've never used Cedar so those more versed in that wood can steer you better but if it is a softer wood, belly wise, sinew may overpower it. Anyone with Cedar experience care to chime in?
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Well, I've always thought the same thing Chris, until lately. TBBIV page 39, says that it is very similar to yew in that it is well matched to sinew, being VERY good in compression. I bought a nice stave at the Hoosier Bow Jam a couple of years ago.
I took some pictures a bit ago and will post them as soon as I can.
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im not sure if the sinew would overpower it but if TBB says its a good match then id probably try it. ive never built with cedar full scale for bows but built a prod for a mini bollista with some cedar shims.lol
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Here are the pictures I promised. First, working the stave on the bow horse an couple of weeks ago.
(http://img.photobucket.com/albums/v210/BonaGlass/videos543.jpg) (http://img.photobucket.com/albums/v210/BonaGlass/videos545.jpg)
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Then where I left it yesterday. The upper limb.
(http://img.photobucket.com/albums/v210/BonaGlass/videos548.jpg)
The lower limb.
(http://img.photobucket.com/albums/v210/BonaGlass/videos549.jpg)
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A close up of the mid-limb knot on the back side...
(http://img.photobucket.com/albums/v210/BonaGlass/videos550.jpg)
...and on the belly side.
(http://img.photobucket.com/albums/v210/BonaGlass/videos551.jpg)
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The knot hole on the upper limb near the tip...
(http://img.photobucket.com/albums/v210/BonaGlass/videos556.jpg)
...and the handle.
(http://img.photobucket.com/albums/v210/BonaGlass/videos554.jpg)
There is also a knot on the handle that will be the upper part of the handle on the arrow side.
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Have any of you all read "The Bent Stick" by Paul Comstock?
His first rule is "Don't panic".
Well I just measured the bow so I could give you the exact deminsions...
The lower limb is 4 1/2 inches shorter than the upper limb. How did that happen???
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The bow is 63 7/8" tip to tip. The upper limb is 30" from tip to fade. The lower limb is 25 1/2" from fade to tip.
If I take 2.5" off the upper limb it will still be a 61" bow. I want to get 50# at 26" draw.
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that ones got tons of character,lol. 60 inch and shorter bows take better advantage of sinew from what ive been told,as far as the knots go try soaking the ones that arent holes with superglue. the ones with holes im not sure, ive seen some people leave them and others filled them. ,maybe someone else with more experience with those type of knots can help. all i know is its best to leave a decent amount of wood around them to do the work for the missing wood and the wierd grain. the one in the top limb might not be much of an issue since its close to nock point, less stress out there than say midlimb.
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if you end up filling the knot with the hole using wood putty, tape a piece of plastic then cardboard over the opposite side that you plan on filling from. mix your putty and push it into the knot,going until you think its compressed as much as possible, then continue to fill till its level with the rest of the limb. i wrap my patches with sandwich baggies then clamp wood blocks over them to get the airgaps out of the putty, figure its kinda like making plywood of sorts in there and gaps are bad.you might find an easier way for you to do it with what you got, this way just works best for me. end result is really strong if you pack it tight, even reacts to tools like wood does with the exception of fine sandpaper of course which gunks up fast.
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When I take 2.5" off the top limb that knot hole will be eliminated. So I leave the extra wood around the other knots as if it will be a selfbow? I've also learned that I need to take off all the sapwood.
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yep from what i know you treat them just as any other selfbow, im not sure how the sinew would affect them but id guess it would still stress the knots the same. you should find out once you get it to tillering phase if they end up stiff. i dont know alot about the sinew but from what i do know it seems like the smart thing to do. frank on here seems to use sinew alot from his posts on here, you could pm him for advice too.
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Bona, I think ERC and sinew should make an excellent bow. ERC is a Juniper(J. virginiana) and the Western Plains Native Americans used sinew backed Juniper for many of their bows. I have a 49" flatbow cut out and somewhat shaped that is 50/50 sap/heart wood that I plan to back with sinew.
I have heard that the sinew will separate the sapwood from the heartwood as it dries but don't know this for a fact.
To get the most out of sinew, short is the trick. For protection of the bows back a single layer of sinew will work like rawhide but with possibly a bit more oomph!
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Thanks everyone for your input. I will still fill a knot hole in the handle section as described. It isn't all the way through but it is also a little torn out from when the stave was split.
I will also take off the rest of the sapwood just to be safe. Along with sapwood and heartwood seperating, in "The Bent Stick", Paul tells of sinew backing a yew stave with sapwood left on that was deflexed by 5" the next day.
Doesn't Gary Davis tie the handle down in reflex when he sinew backs his bows? The sinew should pull the bow into reflex anyway, so is this for insurance?
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If you are going to sinew back it I would leave the sap wood on and just get the back flat. Put a block on each end and pull into reflex at the handle and sinew. The sinew and cedar are a good combo, I am tillering one just like it right now and have shot many of Ed Scotts bows made out of the same stuff.
Mike
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Hey Mike, thanks for the advice. I've already taken off alot of the sapwood. I haven't been able to get it all off, so I will stop trying. It is pretty flat now, so I'm ready for the sinew.
Do you think 50# @ 26" will be ok? It should end up 59" nock to nock.
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(http://img.photobucket.com/albums/v210/BonaGlass/videos564.jpg) (http://img.photobucket.com/albums/v210/BonaGlass/videos562.jpg) (http://img.photobucket.com/albums/v210/BonaGlass/videos565.jpg) (http://img.photobucket.com/albums/v210/BonaGlass/videos567.jpg)
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That will work, I would put more than just a dusting of sinew on though. Put at least an ounce and a half on each limb and fill that knot hole with wood dust and glue. I am shooting for 55-60 lbs on mine now. I will put some pictures up as it gets there. I have others that I have to finish first.
Did you ask me about some rattles to put on a fiddle a few years back, if you did I have some small ones now that I can send ya no charge.
Mike
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No Mike that wasn't me.
But I'm very interested in seeing your finished cedar bow. Thanks again! Oh that knot is in the handle section. But I still plan to fill it like you said.
Bona
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glad someone could chime in who has experience in what you want to do. hope it turns out well.
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I would like to use whitetail deer or bison sinew, but all I have is ostrich. It's nice and long but if it's not enough to do the whole job I might as well wait a few days and get what I really want and save the ostrich for tying stuff.
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Oh, I have another question. I want to put elk antler nock overlays on it. Should I leave a space unsinewed and put the antler directly on the wood or can I put it on the sinew?
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i wouldnt know from experience with sinew but i generally leave my tips unbacked and wrap over the transition from backing to tips with some thread saturated with superglue, this keeps me from having any issues with gaps or adhesion to my backing.
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I put the first course of sinew on my bow last night. I should have reread this thread first though because I don't know how much I actually put on there. I might be able to guess.
I went ahead and put sinew over the nocks. Figured I could scrape it off if I needed to and I would have a smooth transition.
Do I need to do anything between layers? Like sanding? And do I really have to let it dry for a month between layers? I can keep it at 50% humidity.
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Bona,
When I've sinewed I put all the layers on at one time and let it sit for a month, perferably under a fan after it started to harden some. But one layer at a time will work, too. I suspect you would not have to wait a month for that to dry as it is so thin.
On the nock issue. Sorry I didn't see this before. I don't sinew right up to the tip but leave a space. I've read that sinew and the string don't get along very well. But, when your layer dries just scrap or sand it back some to reveal the wood tip area. This material sands very well. The antler tip will hold much better to the wood than it will to the sinew backing. Remember, sinew can be peeled from a bow on occassions, you don't want your overlay tip to ever do that.
Between layers you shouldn't have to sand as the dried glue will reactivate when wet glue is applied.
Looking forward to your finished bow's pictures.
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Thanks Chris. I think I will go ahead and try to get the rest of the sinew on today. I am pretty exited about this bow. It actually looks like the sinew backed bows that I've seen!
It started kinda slow. I was only using three strands in my bundles thinking slower would be better. But I found that eight or ten strands to a bundle made it easier to see where the sinew was and where I needed to put more. And it was faster. My back was killing me before I was done.
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I've only made a few sinew backed bows and on all I added 3 layers and allowed a month between each layer. I have heard about doing it like this or all at once and I don't think there is much difference.
Bona, If your sinew isn't completely dry your bow will increase in draw weight as it dries more. I think once the sinew gets transparent and feels dry to the touch it will not separate from the bow if all was done properly. Also remember that the wood will absorb moisture from the sinew and glue and that moisture has to dissipate too. You don't want to seal a sinew backed bow until the moisture is out of the sinew, glue and wood.
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Yes, It makes alot of sense that the wood picks up moisture from the sinewing process. I will wait plenty long enough before starting to tiller and especially sealing. Thanks Pat.
I put more on the bow and would have had it done last night if not for having to process more sinew first. Mike suggested an ounce and a half per limb. I converted grains to ounces and that turned out to be 437.5 grains per ounce. That meant I only had 1/2 ounce on the whole bow after the first application.
Processing sinew and applying the sinew goes much smoother with just a little bit of experience. I guess the proof will be in the pudd'n.
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(http://img.photobucket.com/albums/v210/BonaGlass/2010026.jpg) (http://img.photobucket.com/albums/v210/BonaGlass/2010027.jpg) (http://img.photobucket.com/albums/v210/BonaGlass/2010028.jpg) (http://img.photobucket.com/albums/v210/BonaGlass/2010031.jpg) (http://img.photobucket.com/albums/v210/BonaGlass/2010033.jpg)
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cant wait to see if this turns out for you, its always nerve racking to see if a new method is going to work but its great to get the additional experience and knowledge gained from it.
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(http://img.photobucket.com/albums/v210/BonaGlass/2010035.jpg) (http://img.photobucket.com/albums/v210/BonaGlass/2010040.jpg) (http://img.photobucket.com/albums/v210/BonaGlass/2010044.jpg) (http://img.photobucket.com/albums/v210/BonaGlass/2010043.jpg)
Done and out getting some fresh air and sunshine. The humidity is low so though it would be good for her.
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Jim Hamm's book says 10 days of drying at low humidity or 14 at higher humidity and it can be worked.
I thought I would take it off the blocks on Mother's Day and maybe start smoothing it down. I hadn't really tillered it, I just got it starting to bend before putting on the backing.
I'm thinking it wouldn't hurt to wait a month until I bend it for the first time.
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Well I didn't wait a month to bend her the first time. I braced her very low. To see how the string tracked.
The string would want to slip off the right side of the bow. I wanted a more experienced opinion so I arranged to show her to John Scifries.
He gave me some suggestions and I worked on her some today getting her to about 4" of brace. The string track isn't perfect but it doesn't feel like the string wants to reverse on me anymore.
A crack had developed while drying in the lower limb from the fade toward a small knot for a few inches. I wrapped the crack one inch below where it started near the fade to an inch past the fade hoping it would go no further aroung the knot.
When I braced it today the crack continued another half inch or so around the knot.
The upper limb is still pretty stiff so I'm afraid I'm not going to hit the poundage I was aiming for. It was 25# at 12 and a half inches. So if you can figure that is 50# at 25 in. I only have and in. to go. I was hoping to have the tiller right at that stage and shoot it in to get 50# at 26".
This computer is giving us problems but I will try to get pics up later.
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Wait a minute it should gain atleast 2# per in. so I should have plenty of room to work with.
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lol. hope you can get it to your target weight and length without it blowing on you, i know very well how nerve racking those stages are. as far as the crack did you saturate it with superglue? ive done this to every crack i had develop in my most recent bows and they turned out very well. just saturate and repeat till the wood doesnt soak any more in then wrap the area. you should be able to get your weight if it was 25@12" no problem, just patch the crack very well and go slowly.lol. my last bow got a crack and i saturated and wrapped it and i got it pulling 45-50#@ 26 and 28 inches. good luck though i know this ones been long in the making.
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That bow should take on more weight as it cures more. You have introduced moisture into the wood that dries slower than the sinew. I would set it aside and let it cure for a month then check the weight again.
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What Pat said, dry wood will pull the moisture from the sinew drying it faster, BUT it will make the wood wet again. If you apply sinew to unseasoned wood the wood and sinew will dry at about the same rate.
Sinew job looks great in the picture.
Mike
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(http://img.photobucket.com/albums/v210/BonaGlass/2010046.jpg)
The upper limb is to the left. I wrapped the way I did because a thin crack was forming in that area. I left a space hoping I wouldn't have to wrap it at the arrow pass. I will wrap it further up the limb after the tillering if it looks like it's going to hold up until then.
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(http://img.photobucket.com/albums/v210/BonaGlass/2010047.jpg)
A closer look at the lower fade area wrapped. Walkabout, I did soak the crack with thin CA several times. Forgot to mention that earlier. You can see it sitting there in the first pic.
Pat, do you think it will harm the process to continue tillering at this point?
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(http://img.photobucket.com/albums/v210/BonaGlass/2010048.jpg)
A closer look at THE CRACK. Wahaha! :scared:
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(http://img.photobucket.com/albums/v210/BonaGlass/2010049.jpg)
This crack developed while sitting in the hot box. It was just starting to come around the knot until I strung it low yesterday. About 4.5". It came on around at that point and it has been pulled no further.
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(http://img.photobucket.com/albums/v210/BonaGlass/2010045.jpg)
Profile at that low brace. I wrote a number "10" on the lower limb and a number "20" on the upper limb where I wanted to scrape which I've done this morning. I haven't restrung it since though.
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I appreciate everyones opinions and thoughts. Keep'em coming.
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Proceed with cautious abandon and tentative hope :) Don't worry about weight. Make it a bow.
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Ya, It's just a bow. :)
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That is very good advice that John gave me. It helps keep things in perspective.
I've taken more off the bow in about the same areas with not much change in profile.
Hey can anyone tell me why the pictures on older posts don't stay. Alot of my pictures are now just a little red "x".
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Originally posted by b.glass:
Hey can anyone tell me why the pictures on older posts don't stay. Alot of my pictures are now just a little red "x".
Hit the F5 key on your keyboard on the pages you see the red "x".
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Oh by the way the bow is looking good. Hope eveything works out.
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Thanks Spike.
I have been off for a few days while the hard drive got an overhaul. I will update as I can. I will let you know that the bow would now qualify as a youth bow. I'm thinking about piking the tips about 1 1/2" and another thin layer of sinew. It would go from a little over 60" to 57".
I'd had about an ounce and a half on each limb but I had put it about half way down the sides. I took that sinew off so to get the amount on that Mike suggested it could handle another thin layer. With all that and more cure time I'm hoping to add a whopping 20#!
I have pics of the tiller. Which isn't perfect. I want to see if you see what I see. :)
John, if you would have that bow class I would do my best to be there!
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I haven't put up new pix yet because I noticed that my son wasn't pulling it from the right spot on the string and the tiller looks worse that it really is. The string had no serving or nock point to give him reference. I need to take another picture but it had been raining alot and ....
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(http://i887.photobucket.com/albums/ac73/mikeyancey/Cedarbow002.jpg)
B.
Here is the cedar and sinew bow that I have been working on since Ed Scott gave me the roughed out bow in Jan. I cut it to 52'' and its 60@26'' real fast and a nice shooter. We will see how long it lasts.
Mike (http://i887.photobucket.com/albums/ac73/mikeyancey/Cedarbow003.jpg)
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Mike, are you using sapwood and heartwood with the ERC? I have a 49" stave I've got shaped and intend to sinew back. I've heard that sinew will separate the sapwood from the heartwood but that was only hear say. I would think that ERC and sinew would be the perfect marriage.
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It has the sapwood as well as the heart.
Mike
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Mike, that is beautiful! I was hoping you would remember to show us.
Mine wasn't working out to well, then it took a swan dive out of my hot box that is like 5' off the ground, tip first of course...I'll have to post a picture of it. Needless to say, I have to look for another stave. :banghead:
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ouch, too bad was looking forward to seeing the outcome of this one. good luck on the next one though, and keep us posted.