Primitive Archer
Main Discussion Area => Bows => Topic started by: Prignitzer bowman on January 23, 2013, 02:23:58 pm
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Hello I recently tried my first sinew backed bow. And am quite happy, but not totally. I was unhappy with a rowan (mountain ash) bow that I made and decided to rework it. So I cut it down worked both the back and the front and then added one layer of sinew using tite bond 3 to the back. The bow works even though I violated the back so badly. It is 55 inches long about 1 an a half inches wide and pulls to 28 inches. But is not very strong I haven't measured the exact strength, I estimate 35 -40 pounds. The wood is not very thick about 7-8 mm (about 0.31 inch?) My question is : can I heat treat the belly without doing something horrible to the sinewed back? Anyone have any ideas other than try it and see. Thanks Peter
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Why not brace the bow backward at about 3-4 inches of reflex and lay down a couple more layers of sinew. That should give you some more draw weight.
Grady
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if you have cut it down to 55 inches...I wouldn't cut anymore..a few more layers of sinew can help and yes either hang a weight from handle or string backwards for reflex...you will have to retill so whatever you gain you in weight you will probably lose in tilling...I suggest you save the sinew and build another bow..light weight bows are fun to shoot and practice good form with anyway..and their ain't a bowyer alive that hasn't missed weight before...
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Yes the heat will make the sinew come losse. When sinew drys it strinks deflexing the wood the wood dos'nt strink only the sinew so it has tention putting a lot of stress on the glue. Any heat it will instintly pop off.
Don't brace the bow backards you don't have to you can add a couple layers of sinew. The sinew will reflex the bow. You don't want to brace the bow more than the sinew will reflex it. Or you'll lose pondage. YOU'LL END UP WITH 2 TO 4 POUNDS PER LAYER DEPENDING ON THE THICKNESS OF YOUR LAYERS.
I'd chalk it up and start over I reused sinew a couple times. It's a mess but you can always heat and boil and reuse the sinew.
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I am not sure the heat will make it come lose if it was glued with titebond..and you don't get the reflexing properties AS WELL with titebond as you do with hide glue..titebond sets much faster preventing the full effect of hide glue and sinew...I have used heat to flip tips that were sinewed and they DID NOT pop off any sinew..however it was not toasted either as in heat treating..
You don't want to brace the bow more than the sinew will reflex it. Or you'll lose pondage. ...never heard that before..
I always reflex my bows by hanging a weight on the handle and letting the sinew dry while it is reflexed and I promise you it didn't lose any poundage ...but I agree ..I think you be best building a new one than trying to repair this one ,toasting the belly isn't gonna give you 10 pounds either..
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I think adding more sinew would be throwing good money after bad. Secondly, I wouldn't waste good sinew by using TBIII. The plastic glue sets up hard long before the sinew really cures and consequently the sinew really isn't giving you it's full potential like you would get with hide glue or unflavored gelatin.
If all you want is a backing to keep the bow from blowing, there are cheaper and easier alternatives.
Sinew is also best when added to a bow designed to be sinew backed, something like a short/narrow bendy handled bow like a Sioux inspired horsebow, or a short/wide Modoc-like paddle bow.
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Yes, I agree with JW! Save your sinew for a new bow and mark this one up as experience . Make or order yourself some hide glue and make a new bow. As far as the heat, I did try to heat treat a hickory bow with a bambo backing glued on with tb3 and yes it did separate.
Knapper
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Thanks for the response. I will leave the bow alone as I don't have the sinew to add to it, and it seems wiser to try a new bow when I do get more. Thanks again Peter
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sorry just thinking out loud here, what about glueing on a lam of wood to the belly? I looked on ebay I can get maple or maybe hickory what would be good for compression? I even started to ponder a lam of carbon? I know not very primitive but what do you think?
Peter
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Please don't take offense to this but you can't polish a turd. If the bow is junk, chalk it up to a learning experience and start on a new one. We learn the most from our mistakes.
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Double O kinda has a point, not elegant, but surely effective! Trust me, I have spent lotsa time with turd polish and a soft cloth. In the end all you got is a shiny turd.
Start another bow. And then another, and another. You're addicted anyway, give in and enjoy the ride!
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sorry Outlaw but they proved you can polish a turd on mythbusters >:D
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I saw that one Bubby. It was shiny but it was still a turd.
Prignitzer bowman, If you were to try all your ideas on how to improve that bow you would likely still be unhappy with it at the end. If you applied all that time and effort on a new bow you would probably have it about done.
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You could actually let the rowan be the core and add a strip of compression strong wood to the belly and go from there.
Marc posted a Cherry bow with a sinew backing that had an Osage belly added after the cherry chrysaled.
Good practice at flattening wood and obtaining a good glueline. I would only do this if the rowan actually has straight grain though.
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Adding sinew to an unsuccessful bow will get you a little farther down the road but it is still an unsuccessful bow with a sinew backing. If you want to build a sinew backed bow styart with that plan and see it through. Trying to make something better by adding something else to it isn't the best route to take.
I missed that Mythbusters(I love that show) but if anyone knows a turd it is Clint. ;) ...and shiney or not it is still a turd!
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well ignored all your advice and here she is 45 pounds at 28 inches is a lot of fun to shoot very smooth, the tiller isn't perfect but it will do. Rowan wood with two layers of sinew.
http://i1152.photobucket.com/albums/p485/prignitzerbowman/th_IMG_0287.jpg
hope this works haven't posted pics here yet
Prignitzer
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ok someone help me please how do I post photos here?
Prignitzer
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copy and paste the img code. I did it for you. Nice job on the bow.
(http://i1152.photobucket.com/albums/p485/prignitzerbowman/IMG_0287.jpg)
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Thankyou osage
http://s1152.photobucket.com/user/prignitzerbowman/media/IMG_0316.jpg.html?sort=3&o=1
http://s1152.photobucket.com/user/prignitzerbowman/media/IMG_0314.jpg.html?sort=3&o=2
Prignitzer
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Damn!! Bloody computers what did I do wrong?
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Just copy and past the img code. It is basically the same link that you have except it starts and ends with [img]