Trad Gang
Main Boards => The Bowyer's Bench => Topic started by: Pat B on January 03, 2023, 02:44:03 PM
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I've decided to switch over from working on the diorama of the Kodiak Bear Hunt to working on Elg Bue, my Hjarno attempt, a 7000 year old bow found in a fjord in Denmark. As all of you might remember(it's been so long) I've shaped and partially tillered this bow and was waiting for winter to add the sinew.
I started by cleaning my work bench in our sunroom(for me, this in clean).
and gathered the sinew, glue, crock pot and other supplies for the process.
(https://i.imgur.com/aClt1q3.jpg)
I set up my form with 2x4 blocks to support the tips...
(https://i.imgur.com/zF5NK1q.jpg)
I usually draw the handle down to the form so the stave is in more reflex for the sinewing. The last few times I've done this I would tie the handle down to the form with sinew and just sinew over this. This time I drilled a hole in the form at the center line, drilled a shallow hole in the back of the handle and used a screw and washers to draw the handle down to the form which gives me a more positive attachment that using the sinew to tie it down...
(https://i.imgur.com/tD2VwGj.jpg)
(https://i.imgur.com/me2ueBP.jpg)
Once I get my head screwed on right I'll start the sinewing process. I'll keep you posted...
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Nice Pat but..
Once I get my head screwed on right I'll start the sinewing process. I'll keep you posted.
I hain't got that many years left:)
:laughing:
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I promise it won't be that long, Roy. I'd hate for you to miss it. :wavey:
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:biglaugh: :biglaugh: :thumbsup:
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I got to ask, is there a technical reason you wanted to wait till winter to do the sinew?
And I back you up on the project hold :saywhat:
Some folks start a project and won't stop till its done. Not me, I have to start a project as soon as I think about it. That way I will have it sitting in the corner of my shop, unfinished, as a reminder of my great idea.
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Phil, I like working sinew in the winter because it is drier and especially in our house with the wood stove. I don't want the sinew to dry too fast though. But once the sinew feels dry the wood of the bow also has to dry from the moisture from the hide glue. I'll keep the sinewed bow on the form until that's done.
I wanted to get this sinew job done so I set the diorama aside because it doesn't have to be done until the first weekend of May for the Tenn Classic. Once the sinewed bow is done I will set it aside to cure and dry then I can get back to the finishing touches of the diorama. My brain, ADD and/or dyslexia doesn't allow me to multitask or else I have too many unfinished projects around. My basement shop is full of them anyway so I don't need to add more to that mix. I still have the hickory backed ALB to finish up too and hopefully I can get that finished too.
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I still have the hickory backed ALB to finish up too and hopefully I can get that finished too.
Yup I hope I make it to see that one done too:)
:laughing: :laughing: :thumbsup:
LOL come to think of it, I have a bow needing finished too:)
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I got to ask, is there a technical reason you wanted to wait till winter to do the sinew?
And I back you up on the project hold :saywhat:
Some folks start a project and won't stop till its done. Not me, I have to start a project as soon as I think about it. That way I will have it sitting in the corner of my shop, unfinished, as a reminder of my great idea.
I've got an osage stave i've been working on for 10 years now...Off more than on... I'm with ya bro.
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Still getting over the holiday slump. That's my story and I'm sticking with it. :knothead:
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Yup Pat, same here. Holidays and surgery..
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I'll be starting the sinewing soon. I realized I had a bit more straightening to do first so yesterday I did that...
(https://i.imgur.com/OT3Fv5g.jpg)
(https://i.imgur.com/AqDkAAi.jpg)
I also decided to rough up the back of the bow for better adhesion. I had some cambium remaining on the back and I didn't want it to impede the sinews adhesion. I got much of that remaining cambium off and scored it well over the remaining little bit. I use a Shinto rasp, dragged sideways along the back and upper edge of each limb and along the back of the handle...
(https://i.imgur.com/EQaboH7.jpg)
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After scrubbing the back of the bow with Dawn dish soap and rinsing with boiling water I sized the back with hot hide glue then a while later I started adding the sinew. Here is where I am now. Not as smooth as I hoped but once this sinew dries I'll sand the rough places and prepare for the second layer of sinew.
(https://i.imgur.com/GnmVxRk.jpg)
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Looking great, Pat...
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Here is what it looks like this morning. It seems to dry pretty quickly but don't let that fool you. There is still lots of moisture in the sinew and the bow wood. I'll add sinew to the voids then see what it looks like.
(https://i.imgur.com/RsqLKkj.jpg)
(https://i.imgur.com/3HAyRJq.jpg)
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Very cool! How long does it take to lay down a layer of sinew?
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Phil, if everything needed is handy only 30 minutes or so, maybe a bit longer.
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I went back and filled the voids left after the sinew dried. Once it dries again I'll check for any voids that may still be there and fill them too. I think this will be all of the sinew I add except for filling the voids. After it all dries well I'll sand the back some, size the sinew with more glue and add the rawhide covering. I use hide glue for that too. I'll give it about a month, maybe 2 to dry more then it will be time to check the tiller once more and adjust. I'll shape the tips(levers) and the handle then too.
Here are pics where I filled the voids...
(https://i.imgur.com/Sd1dJsl.jpg)
(https://i.imgur.com/gLsROxV.jpg)
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Sweet...
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By 2:30 today the gap filled sinew were dry enough to blend in. That's why I prefer to sinew back bows in the winter.
(https://i.imgur.com/nxJmPqj.jpg)
(https://i.imgur.com/1sejTIh.jpg)
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I can tell the sinew is working this morning. Even only one day after adding the sinew to fill the voids and only 2 days after adding the bulk of the sinew I can slide a piece of paper under where the tips rest on the uprights of the form. The tips are lifting off the uprights. There is no pressure there at all. As the sinew continues to dry and shrink it may come off the uprights even more.
Since this is the first time I've made my own sinew glue I was worried about how strong it actually is. I won't really know until the bow has been shot in but so far I'm very encouraged. :thumbsup:
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:thumbsup: :thumbsup: :campfire:
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When I looked at the bow today sitting in our sunroom I noticed the tips have lifted off the reflex blocks. That sinew and sinew glue are doing their work.
Before adding the sinew with the limbs sitting on the blocks the handle was at least 1" above the form base...
(https://i.imgur.com/zF5NK1q.jpg)
Just a few minutes ago when I went and looked, this is what I saw...
(https://i.imgur.com/9v6nARZ.jpg)
(https://i.imgur.com/B7grA9H.jpg)
(https://i.imgur.com/l31Y3XA.jpg)
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Pat, with all that reflex, that will be a "fun" tiller. Sinew looks good. Jawge
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Yeah, George, just getting the bow into deflex on the tiller tree will be interesting.
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Damn that's awesome...
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I'm surprised too, Roy and only after 3 or 4 days after adding the sinew. What will it look like in a month? :o
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LOL...
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The sinew seems to have stabilized at least it hasn't drawn the bow into any more reflex in the last few days. I want to study the sinew backing and add a bit more where needed. Once that dries I have some very thin rawhide that I want to cover the sinew with.
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You going to do some Neolithic cave art on that rawhide? :cheesy:
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I have some similar plans, Phil. :thumbsup:
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I did a little more work on this bow yesterday. I sanded the sinew back with 80 grit sandpaper to smooth it somewhat, to get the predominant lumps out...
(https://i.imgur.com/xnwZA0q.jpg)
then I resized the sinew back with hide glue...
(https://i.imgur.com/dz3fJM7.jpg)
in the mean time I separated out a few choice strands of sinew to fill in the thinner sinew areas on the back...
(https://i.imgur.com/Evee5q1.jpg)
...and added sinew where needed...
(https://i.imgur.com/qWAY6eS.jpg)
...after a little while I noticed the sinewed limbs had relaxed a little because of the introduced moisture of the hide glue and sinew. The tips were sitting back down the blocks. This morning I noticed they had come off the blocks a smig so the moisture is evaporating again. I think I'll be adding the rawhide today and then let it dry for a while. Once it dries some I may start shaping the handle and tips.
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Here are pics of tips back down on the blocks...
(https://i.imgur.com/of6tSqe.jpg)
(https://i.imgur.com/p1AbI95.jpg)
...and the drying sinew this morning with the more even sinew...
(https://i.imgur.com/aagTkBJ.jpg)
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Very nice, Pat
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Thats a lot of tension! Hope that bow does not get tendonitis :laughing:
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Nice pat what kind and how thick is the rawhide??
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Mark, I believe it is deer and it is very thin, about like typing paper.
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Looking good Pat.
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:thumbsup: :bigsmyl:
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Thanks, Bue. That elg sinew is wonderful stuff. :thumbsup:
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After the sinew dried for a day I decided to add the rawhide backing so it could all dry together. I sanded the sinew back again to smooth it out somewhat then prepared to add the rawhide. I first hydrated the rawhide in warm water...
(https://i.imgur.com/Y2gtXfu.jpg)
...then washed it well with Dawn and warm water then rinsed it well and put it back in warm water so it would stay hydrated...
(https://i.imgur.com/hhJxdZS.jpg)
(https://i.imgur.com/TDvyWJq.jpg)
...then I rolled the wet rawhide in paper towels to get the excess moisture off of it...
(https://i.imgur.com/oIL38qw.jpg)
...then it was time to size the sinew back and the rawhide before putting them together. I did this twice over about 30 minutes to ensure good adhesion.
(https://i.imgur.com/0RhYHEQ.jpg)
I only do one limb at a time and overlay the rawhide pieces at the handle. Once the rawhide is in place I wrap it with strips of old bed sheets for about an hour. The strips of old sheets allow the moisture to evaporate as the strips hold the rawhide to the back...
(https://i.imgur.com/FnFPF5f.jpg)
After an hour I I remove the cloth strips and check the rawhide for trapped air and excess glue. I work them out with my thumb. If that doesn't work I use a sharp razor to make a small slit lengthwise and push out the air and excess glue.
(https://i.imgur.com/hDpG2uu.jpg)
Once both limbs have been covered with the rawhide it's time to set the bow aside to let everything dry.
This morning I trimmed the excess rawhide from the sides and belly of the bow. And now the waiting game begins. I'll probably give the bow at least a week to dry. With the wood stove in our house and even with humidifiers running things dry our pretty quickly.
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Looking good Pat.
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Can’t wait to see it finished. I have used a very thin rawhide from Reindeer and one time I found a couple of air pockets after it was dry. I filled a syringe with thin hide glue and injected glue through the rawhide and gave it a massage, worked fine. Kept the syringe in warm water.
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:clapper: :jumper:
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What kind of glue did you use for the snew and rawhide backing Pat? That is quite a process you are doing there….
Cleanest shop I’ve ever seen too. :biglaugh: I need to call my interior decorator to pick out curtains now. Kirk
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Thats a lot of physical mass being added to the bow. Have you ever weighed a bow, before and after the sinew, glue and rawhide are applied?
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That’s a very cool process Pat great job!
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Thats a lot of physical mass being added to the bow. Have you ever weighed a bow, before and after the sinew, glue and rawhide are applied?
According to Tim Baker, sinew is the only backing that will actually add to the bows performance.
Not something that I personally know anything about. 😌
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Not that much weight added :bigsmyl:
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Sinew and hide glue do weigh more than wood but the elastic properties of the combo helps to negate that extra weight. Sinew, unlike FG stretches and recovers which gives that elastic property that imparts the better performance.
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How many # of draw weight will it add?
How many # would the bow be without the sinew?
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FG stretches and recovers. Maybe not as much as sinew, but if it did not, there would be thousands of exploded bows and a bunch of maimed archers. :tongue:
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Mark, I'm shooting for about 45#. The sinew could add 10# so if it does I'll tiller it back down to a usable weight.
Phil, obviously I don't know much about FG but I guess it would have to stretch and recover some or else, like you said it could be trouble.
I checked the bow this morning and the tips have raised back up off the blocks...
(https://i.imgur.com/xm1aNyP.jpg)
(https://i.imgur.com/bKsu2Fe.jpg)
...and here is the rawhide covering the sinew...
(https://i.imgur.com/j3tzGbd.jpg)
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FG stretches and recovers.
This is correct. All materials deflect under load and then return to their original shape when the load is removed. This happens until the load exceeds their yield/failure limit and permanent deformation or failure occurs. The differences are how stiff the material is. If we take a good bow hardwood like hard maple as the baseline, sinew is about half the stiffness and fibreglass is about 3x the stiffness. This is why it's harder to see the stretch of FG as compared to sinew, it just deflects much less for any given load.
Mark
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Thanks, Mark. That's helpful to know. :thumbsup:
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I think it’s cool as hell you guys have so much fun with these old school self bow methods. It’s gotta be pretty satisfying when one comes together nicely, and holds up over time. Hat’s off to you guys! :notworthy: :notworthy:
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February 16 will be 2 weeks since I added the last sinew and rawhide backing so then or sometimes shortly after that I will work on bracing the bow. :saywhat:
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First brace on a glass bow with masking tape, the belly side shows wrinkles in the tape. :saywhat:
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Compression effects on the tape?
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Compression effects on the tape?
Pat, I think he is off his meds again:)
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Compression effects on the tape?
Yep.
Mark
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That must be my deal, wrinkles on the belly! :laughing:
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...and elsewhere for most of us, Kenny. :thumbsup:
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Compression effects on the tape?
Yes the tape is showing you that the belly is compressing.
I'm sure you could draw 2 lines 6" apart on the back and it would be a little longer at brace.
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I'm sure you could draw 2 lines 6" apart on the back and it would be a little longer at brace.
You wouldn't be able to easily measure the difference over a few inches, but it would be measurable from nock to nock. If you take something easy to measure along the back like a Hill longbow design with several inches of reflex unbraced there will be around a 1/4" (or more, depending on the details of the design) increase in the nock to nock length from unstrung to braced.
Mark