Primitive Archer
Main Discussion Area => Bows => Topic started by: WhistlingBadger on March 05, 2024, 02:32:17 pm
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Well, here's my latest project. Some of you might remember I badly scorched one of the tips with some over-zealous heat treating. I scraped it down to sound wood and glued on a lamination from a hickory backing strap I had laying around. I'm backing it with dogbane fibers from just up the mountain here, processed while watching tv with my girls. :) Elk antler on the tips. Put two layers of fibers on the back; now letting it dry for a couple weeks before I start tillering.
(https://www.fishforums.net/attachments/img_0890-jpg.338112/)
(https://www.fishforums.net/attachments/img_0891-jpg.338113/)
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I remember that one WB.
I had some dogbane once. It does make nice fiber.
Bjrogg
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I remember that one WB.
I had some dogbane once. It does make nice fiber.
Bjrogg
I've made two-ply twine out of it, and it is seriously strong stuff! Probably would make a bow string if I trusted myself with that. Might try using it for sewing thread on my next leather project, though.
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Excellent choice for backing WB. dogbane is one of the strongest natural plant fibers around and will definitely make a bow string also. took the family to Gila cliff dwellings many years ago and was very surprised to learn that the people their used ladders and ropes made of dogbane to access the caves there . Strong stuff.
Please keep us posted as to how it performs, I have considered using it as such myself.
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Looks good. And yeah dogbane is awesome stuff. Can't wait to see it finished.
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Yea cool project and a good way to save the project. I’ve never used dogbane but on my list of things to monkey around with for bow strings.
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Nice, can't wait to see it all finished up. :)
Pappy
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OK, got this thing bending and had it to 55# at around 6" on the tree when the backing popped and an insta-hinge appeared. (Yeah, this is seriously strong stuff!) I got the pressure off it instantly, and the underlying wood seems undamaged.
(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_-jfIBCvyae2UOX44EDucciYxTziiClamFLzFCnerSwNtCm7hebO8TuEtjOBI4wZBIIPjkH0Chf72XUFDGJMRcV_q9rjiaRL0rFs23dN_ZCJvAxiaY05hOer3so0zrtvwiBIebXyVWUdUMiEltRZpwJ_m22QJ0iQZUvhAZaHH8eJ9gYrCYsV07BY5WKY/s4032/IMG_0909.HEIC)
Any ideas why this might have happened? And what now? Could I put another layer of fiber over the bad spot? Fiber backings are new to me, though I did screw up a sinew backing once.
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Hard to say WB. Maybe starved for glue??? I’ve never used dogbane it’s on my list of things to try out
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Hard to say WB. Maybe starved for glue??? I’ve never used dogbane it’s on my list of things to try out
You might be right. I also wonder if I mixed my glue too thin. I think I'll paint the whole back with a layer of glue, then put a couple of layers over the break. Then let it dry a couple weeks and continue tillering. If it breaks again, I might just peel it and start over. I wasn't as careful applying this stuff as I should have been. I think a lot of the bundles were twisted, so the back didn't lay down smooth and I wonder if the fibers didn't adhere well. That might be my problem too.
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What glue are you using? I've done 2 that I backed with dogbane and a couple others with sisal fibers and I used thinned tb3. These all adhered really well
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What glue are you using? I've done 2 that I backed with dogbane and a couple others with sisal fibers and I used thinned tb3. These all adhered really well
how did sisal compare to dogbane with the ones you backed?
did you back with fibers to help out an iffy back or maybe apply enough to act as a load carrying lamination, like a bamboo backing?
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Willie, both seemed ok, but the dogbane is definately stronger. Of those 4 bows I mentioned 2 have failed and 2 are still alive. The 2 that failed were tiller issues. The sisal bow that broke ripped right through the backing, but the dogbane one still had an intact back, just sort of folded as the wood failed. Not extensive in comparison, but the dogbane is certainly stronger.
These bows were backed not for performance, but rather as insurance against my rookie bow making abilities. They were also board bows and the 2 failures were both red oak.
I started a thread about these backings a while back and there were some suggestions on sisal by Joachim using hide glue and inducing reflex with sisal as it stretches more than the dogbane would. This might have some performance gains? Can't say I have enough experience with it to say though.
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What glue are you using? I've done 2 that I backed with dogbane and a couple others with sisal fibers and I used thinned tb3. These all adhered really well
I'm using hide glue aka knox gelatine.
did you back with fibers to help out an iffy back or maybe apply enough to act as a load carrying lamination, like a bamboo backing?
A little of both. This bow is hickory heartwood, and I don't have the patience to chase rings at this point in my life, so I decided to back it. The dogbane does seem to add some weight to the draw. It's basically putting a couple layers of wood back on.
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years a go I prepared a couple of dozen samples did some bend testing.
as I recall, 1/2 were hide glue and 1/2 were epoxy. in each half, 1/2 again were backed with flax and 1/2 again were a synthetic backing
both backings were stronger than the wood and the more backing aplied, the earlier the sample took set.
both hide glue and epoxy performed the same at typical bow stress levels.
In the future, I would use a fiber stronger than wood to reinforce an iffy spot on a back.
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Well, I repaired the broken backing. Got one crunchy sound that I think was just excess glue, but fairly smooth sailing since then.
Here it is at 40# on the long string. Target weight is 55#; I plan to tiller it to 60# then scrape it down a bit. Hopefully it will stabilize around 50# after it breaks in.
Opinions, please: I'm seeing that the right limb is a little stiff. Left limb had a bit of a hinge just off the fade, but it's looking better and curving more evenly now. What say you?
(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbBD0IgQGC23SMphh3RpAAUKqOojLiEnI0YA5jNtCbu3WhM7WOivlgsyxUu208Nz2kLK91B4kktB1FBo-9A0ySWA1AFmwUUJDV_U301lisvu_iOTDcQRw5F_NG8SQMo_pSWzIz1_vZlWaOqEOIT6uPJ6hco8elKWhgo9kpcYa-iHAMoNA8EyqaR3CHAMI/s16000/bow.jpg)
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Well, I repaired the broken backing. Got one crunchy sound that I think was just excess glue, but fairly smooth sailing since then.
Here it is at 40# on the long string. Target weight is 55#; I plan to tiller it to 60# then scrape it down a bit. Hopefully it will stabilize around 50# after it breaks in.
Opinions, please: I'm seeing that the right limb is a little stiff. Left limb had a bit of a hinge just off the fade, but it's looking better and curving more evenly now. What say you?
(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbBD0IgQGC23SMphh3RpAAUKqOojLiEnI0YA5jNtCbu3WhM7WOivlgsyxUu208Nz2kLK91B4kktB1FBo-9A0ySWA1AFmwUUJDV_U301lisvu_iOTDcQRw5F_NG8SQMo_pSWzIz1_vZlWaOqEOIT6uPJ6hco8elKWhgo9kpcYa-iHAMoNA8EyqaR3CHAMI/s16000/bow.jpg)
Yes I would agree with that. Some scrapes off right limb and see where you are at then. Maybe little mid limb scrapes on the left one too. Looking good though. Be interesting to see how that backing holds up for ya this time.
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Moved the tillering tree inside the garage and attached it to studs with 4" screws, instead of just into the side of the house. It occurred to me the other day that if it popped loose at 50# of draw, it was going to hurt, and possibly make my face look even worse than it already does.
Got the thing to about 45# and the bends are looking decent, before it made another scary crunch sound. No visible tears in the back, but I think it popped loose in one spot. Maybe I missed a spot degreasing? I don't know. It's about the same place that it broke before, so maybe it just isn't connected down there. Watch this and see what you think.
https://youtu.be/rlt-TBpWSDA
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I think your assessment is correct. The sounds difference is pretty evident something came delam under there. It’s looking great though. How are you glueing this down? Are you using hide glue and what strength. Also are you ensuring a good size coats are done prior to adding the backing fibers. I’m saying this as I’m assuming you would do the same size coats for dogbane fibres as you would with sinew fibres. I size coat with very thing watery hide glue till it gets shiny when dry. Sometimes depending on the core and how pourus it may be this could take several thin coats to sink in deep into wood core. This helps immensely with adhesion of backings like fibers. Just a thought.
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I think your assessment is correct. The sounds difference is pretty evident something came delam under there. It’s looking great though. How are you glueing this down? Are you using hide glue and what strength. Also are you ensuring a good size coats are done prior to adding the backing fibers. I’m saying this as I’m assuming you would do the same size coats for dogbane fibres as you would with sinew fibres. I size coat with very thing watery hide glue till it gets shiny when dry. Sometimes depending on the core and how pourus it may be this could take several thin coats to sink in deep into wood core. This helps immensely with adhesion of backings like fibers. Just a thought.
Yep, I used hide glue. Not sure how to explain what strength...I try to mix it about as thick as pancake syrup. I did size the back with a single layer of glue; made it nice and glossy.
Here's what I think might have happened. The first time I started bending it, the backing broke. I suspect I had a seam in the same place on both layers and that's why it broke. (that's just a guess) Whatever the case, when it broke I think it delaminated for a few inches. Gluing a couple layers over it fixed the break, but didn't fix the delamination.
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Ah yes. Makes sense.
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You know, I shouldn't have posted about this in two different threads. Thanks for responding to both. ha ha
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Well, got this beast back on the tree today. Had a hinge developing where I put the patch, so did some work around that. Had a few crunch sounds early on; hopefully just glue cracking. Was about to string it up for the first time when one of the antler tips popped off. Glued it back on with some TB3; will string it up tomorrow.
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Glue may not be dry enough.
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Well, I got it braced and it looked really nice, but the glue delaminated in the same spot again.
Glue may not be dry enough.
On the tips, you mean? The bottle says you can stress joints after 24 hours. Or do you mean the hide glue? I figured two weeks was plenty of time here in dry Wyoming.
Anyway. Might put this away and work on something else for a while...