Primitive Archer
Main Discussion Area => Bows => Topic started by: willie on May 01, 2018, 10:31:07 am
-
What are your experiences with glues and backings other than sinew? Recent experiments may show that sinew and hide glue together do not work as commonly thought. Does this mean that other combinations could use more investigation?
-
What’s your source?
-
In what ways not as thought willie?
-
In what ways not as thought willie?
it's commonly said that when sinew dries, it puts tension on the back of a bow
-
How does it not?
-
Never without hide glue with it which is commonly understood.We might be looking from different views here.Not sure what you mean.
-
How does it not?
Pat, smooth out some wet sinew, like it would be before putting on a bow. clamp the ends and let it dry. tell me what happens when you release the clamps.
-
Clamp it to what? A flat surface? Between two struts?
-
Here’s my list of backing attempts with some comments on my experiences.
1 - Red oak backed white ash. The oak over powers it a bit, but a long narrow bow with 2” of perry and youve got yourself a very sweet shooter that’ll take about an inch of set. This combo is a favorite because i can cut my stock to near finished dimensions based on experience and ash is a dream to scrape and tiller.
2 - Linen over about any anything but my most successful was over a wide white oak paddle bow with frighteningly narrow tips.
3 - Flax cord over HHB - good combo but kinda ugly. And it stacks firmly at about 29” of draw. The bow is 1 3/8” wide and 67” long at 46lbs. Like this combo.
4 - Raw Flax roving over Osage. It broke as the stave was knotty and had some bug damage. Raw
Flax is very strong and i use it more for wraps as it seems to overpower everything. One of the most interesting things i did with raw flax is to stiffen a bendy handle bamboo osage bamboo ALB. (As a side note i wrote here once that I used sinew for that but it was flax roving, i just looked at it the other day when my nephew was shooting it) It was bending too much in the handle so i laid down flax roving from fade to fade on top of the boo and wrapped the ends of the courses with roving. Worked out very well but pretty crude looking.
4 - Bamboo and Hickory. What can you say? Tried and true. Always with TB II or Elmer’s Max.
5 - Sinew with Tite Bond II or Elmer’s Max. I like these glues better than TB III for reasons i can’t explain. TB won’t magically pull a bow into reflex like hide glue but if you reverse string the bow while the glue is curing you won’t be able to tell the difference next to hide glue except by appearance and cure time. It still takes a week to 10 days to reach full potential. Once the reflex cures in i find it to be indistinguishable from hide glue and sinew as long as you reverse string the bow to cure. If you don’t it does not perform as well as hide glue.
6 - Rawhide - you can have it. It’s saved me from a cut face at least twice but i think it only prevents explosions. I don’t think it makes my bows any stronger or safer.
7 - Sinew over linen. Dumb idea; the linen never allowed the sinew to do its work. Linen over sinew might be cool but unecessary.
8 - I’m floor tillering a quarter sawn 3/16” red oak backing over a quartersawn Osage timber right now. Based on prior experience i have really high hopes for this one.
I’ve thought a fair bit about pulling strands of bamboo garden stake into fibers and treating them like sinew or roving but I’ve never tried it. One day i will.
I’m conjuring up a silk stretching jig to try a stressed silk back design but have not
Attmpted it yet.
-
Clamp it to what? A flat surface? Between two struts?
your choice, but a flat surface would give you something to make marks on. Comparative measurements would be nice.
-
What’s your source?
I have moved this over from Eds thread
Ed, I just measured the three grades of glue I used to duplicate he TP test mentioned in the other thread.
weight water:glue ratio shrinkage
379 3:1 10%
251 2.25:1 8.5%
251 5:1 8.5% this mix was twice the recommended water
135 1.25:1 8%
I should note that the three different weights of hide glue, when mixed with the recommended amount of water, had pretty much the same viscosity.
This compares with 17% shrinkage that was reported with knox in the other thread.
I do not know how fair this test is, as the tissue is free to shrink. When glue is bonded to wood, one side is restrained.
I also dried some deer backstrap sinew. the sinew was restrained somewhat, as I suspected that just drying a strand of sinew unrestrained would allow it to shrivel more than it might if it was in matrix with glue. Three different pieces showed very little shrinkage. The pieces were placed between two slats of cedar held together with a few wraps of electrical tape. They were stuck to the wood when the slats were separated, and when free from both pieces, measured 1% shorter than the razor cuts made when the sinew was trimmed wet before the slats were sandwiched. Not a calibrated test by any means, but my impression is that it did not take all that much to prevent shrinkage, so the idea of it being "tensioned" inside a cured matrix seems dubious, and if it is in a matrix with glue that shrinks more, then what does that say about our understanding of the mechanics?
Link to glue specs and info
http://www.primitivearcher.com/smf/index.php?action=dlattach;topic=63182.0;attach=139366
-
You need to measure the shrinkage unrestrained or stuck to a material that can actually be moved by the sinew shrinking.
Sticking it to something that is stiffer than a strand of sinew has the power to move does not tell you much.
-
How does it not?
Pat, smooth out some wet sinew, like it would be before putting on a bow. clamp the ends and let it dry. tell me what happens when you release the clamps.
When it’s clamped down it’s not allowed to shrink. How about you soak it, stretch it. Measure it. Let it dry and measure again. THEN say it doesn’t do anything.
But it will shrink.
-
Baugh got a measurement of 3% for sinew shrinking.
Again, it comes down to the matrix combination of materials.
You wouldn't really say carbon or glass seem like very stiff materials if someone handed you a strand. Because they are not really until you add the glue.
-
Never without hide glue with it which is commonly understood.We might be looking from different views here.Not sure what you mean.
Let me bring this over from your other thread
Really this brings a thought to mind.If a person ever makes hide glue for themselves they will see the dramatic shrinkage that it does............ Hide glue IMHO opinion has super enhancing qualities with sinew making the sinew even more resilient.
Indications are that the glue does more shrinking than the sinew. Not sure what that tells us about being super enhancing, but examining the process behind your commonly held opinion is certainly part of the reason I opened this thread. Sinew and hide glue work well, no question about it. My thought is that it may not be for the reasons frequently surmised. Perhaps understanding what happens in the matrix can make for better utilization of other combos.
-
When it’s clamped down it’s not allowed to shrink. How about you soak it, stretch it. Measure it. Let it dry and measure again. THEN say it doesn’t do anything.
But it will shrink.
Of course, I prefer to say it shrivels, as it doesn't seem to exert much contraction force when it shrinks. Or at least, it did not take much to overcome the contraction in my experiment. Just being loosely stuck to the side of a roughly sawn WRC slat was all it took.
Any experiment you could undertake to quantify a contraction force would be welcomed. :)
-
Baugh got a measurement of 3% for sinew shrinking.
Again, it comes down to the matrix combination of materials.
Pat,
Baughs test tendon was unrestrained. I believe your assertion that a matrix having it's own properties is right on, Its a new animal, just as crossing a coon hound and a poodle would make...... a mutt.
You need to measure the shrinkage unrestrained or stuck to a material that can actually be moved by the sinew shrinking.
Sticking it to something that is stiffer than a strand of sinew has the power to move does not tell you much.
Yes my test was not very quantitative. A better test would be?
-
Secure a strand to s thin slat at either end and see if it reflexes the slat. Or tack it to a couple of slim dowels pegged into a board and see if it draws them slower to together when drying.
We also tend to reflex a stave rather than just applying sinew to a flat stave. That allows the backing to start off effectively shorter even if it didn't shrink at all.
Looking for another natural mixture seems a like a bit of wasted effort just because we don't know exactly how something works. It's more important to know that it does.
-
HoosierF
thanks for taking the time to share your experiments. Much food for thought.
Especially
5 - Sinew with Tite Bond II or Elmer’s Max. I like these glues better than TB III for reasons i can’t explain. TB won’t magically pull a bow into reflex like hide glue but if you reverse string the bow while the glue is curing you won’t be able to tell the difference next to hide glue except by appearance and cure time. It still takes a week to 10 days to reach full potential. Once the reflex cures in i find it to be indistinguishable from hide glue and sinew as long as you reverse string the bow to cure. If you don’t it does not perform as well as hide glue.
To me, your experience seems to indicate potential for some possibly lighter weight combos. Possibly with plant fibers?
You were getting results in a week to ten days? Makes me wonder what an extended cure time would do?
-
What about horsetail hair with titebond, glued up in reflex?
Just thought about that latley as I read the "Human hair for bow belly"-thread / Probably somebody did already do it if it was a good idea.
Cheers
-
Extracted plant fibers are actually heavy. Also within a glue matrix they are really hard to glue so that they do not move and slip within the matrix.
In essence a unidirectional plant fiber backing is an attempt to make a strip of bamboo. Might as well use what's already there.
-
Secure a strand to s thin slat at either end and see if it reflexes the slat. Or tack it to a couple of slim dowels pegged into a board and see if it draws them slower to together when drying.
We also tend to reflex a stave rather than just applying sinew to a flat stave. That allows the backing to start off effectively shorter even if it didn't shrink at all.
Looking for another natural mixture seems a like a bit of wasted effort just because we don't know exactly how something works. It's more important to know that it does.
If we purposely reflex the stave before application of the matrix, it might be said that the benefits come from just reflexing the stave as much as from the makeup of the sinew or hide glue it's self.
If you think experiments along this line are wasted effort, I guess you will not be testing any sinew as you suggest?
Extracted plant fibers are actually heavy. Also within a glue matrix they are really hard to glue so that they do not move and slip within the matrix.
In essence a unidirectional plant fiber backing is an attempt to make a strip of bamboo. Might as well use what's already there.
I see bamboo fiber on the yarn market. Perhaps suitable for bow designs that would be difficult with a bamboo slat?
-
Natural fibers generally need chemical treatment somewhere along the line to either extract them or really glue them well. Often very complex and environmentally unfriendly. Bamboo being one of the worst, if not the worst.
Sinew, not so much.
-
I see bamboo fiber on the yarn market. Perhaps suitable for bow designs that would be difficult with a bamboo slat?
Willie -I did a little investigating(not much) a while back and what I found says that the bamboo fiber is more like a rayon making process. It didn't seem to be actual fibers from the boo. I may be wrong. :D
-
hoosierf.....Nice contributions of experiences you have about backings.Your an experimenter and that's good.I'm a user of combed flax myself to fix things on bows.
I'm wondering if you kept track of the amount or percentage of reflex that your sinewed bow kept after tillering and shot in done with TB II glue?You know there's a reason the asians don't use TB II with sinew on their horn bows.
-
Don, now that I think about it, the fibers I was looking at looked pretty refined. One of the great Chinese inventions besides gunpowder, crossbows and the compass, was paper money printed on an improved bamboo paper. Interesting reading........
-
Also remember that reflex is often just pulled in on a sinewed bow by reverse bracing. We do also tend to heat treat it in as well but it bears mentioning that it often is just the glued backing retaining the reflex, in which case it is responsible alone.
-
I would love to know if shrinking sinew does in fact have enough force to pull or increase the reflex is a bow or if it is just the reflex put there at glue up.. I know that sinew shrinks as it dries, but so does rawhide.
-
Before people got into reverse bracing, sinew backing was well known to cause long term reflex acquisition.
-
Morgan...the way I understand it and from experience here the make up and pattern of fibers of rawhide are different than sinew laid in line along a bows' back.Reason rawhide will stretch and not come back.It takes set.
Fibrous backings like linen or flax will do the same thing.They will take a set.
Sinew in conjuction with hide glue has a spring back action or resiliency that other backings don't.I'm speaking of more extreme reflex than put in with a wood backing.Wood will only stretch 1% so they say and I think it's true.In fact let a hide glued sinewed bow rest and you will see it go into reflex as it sets.One thing that amazed me about these composites.It's like they are alive even more so than a self bow.
-
Also remember that reflex is often just pulled in on a sinewed bow by reverse bracing. We do also tend to heat treat it in as well but it bears mentioning that it often is just the glued backing retaining the reflex, in which case it is responsible alone.
So some boywers like to reverse brace in order to encourage the shrinkage? Are there pros and cons?, or different schools of thought about how aggressive one should assist the shrinkage? I realize that there are many designs out there, and more than a few eastern traditions that I wish I knew more about.
-
That can be a personal choice a lot willie.Once a person gets used to tillering extreme designs they seem to go back to it occasionally.
-
When I did my only sinewed bow I put a some reflex by stringing it backward. The string kept going slack. Something was pulling those tips together.
-
That can be a personal choice a lot willie.Once a person gets used to tillering extreme designs they seem to go back to it occasionally.
By saying "go back to it" you mean that the technique is used selectively? Can you help with the whys and why nots?
-
Also remember that reflex is often just pulled in on a sinewed bow by reverse bracing. We do also tend to heat treat it in as well but it bears mentioning that it often is just the glued backing retaining the reflex, in which case it is responsible alone.
So some boywers like to reverse brace in order to encourage the shrinkage? Are there pros and cons?, or different schools of thought about how aggressive one should assist the shrinkage? I realize that there are many designs out there, and more than a few eastern traditions that I wish I knew more about.
Almost everyone seems to reverse brace now. It does elminate potential for the backing to separate as the outside dries faster than the interior if you do one thick layer.
-
When I did my only sinewed bow I put a some reflex by stringing it backward. The string kept going slack. Something was pulling those tips together.
That's right DC.Usually no matter how far I reverse brace it.It will slacken the string and gain another good 3/4" on it's own.After a couple weeks the string is no longer needed.It'll hold on it's own.
That can be a personal choice a lot willie.Once a person gets used to tillering extreme designs they seem to go back to it occasionally.
By saying "go back to it" you mean that the technique is used selectively? Can you help with the whys and why nots?
They are just fun to make and shoot.Very durable also.At least for me anyway.I like preparing one then moving on to make more self bows while it's curing.I'm learning to leave them cure a bit longer each time I make one for reasons of gaining poundage.
-
hoosierf.....Nice contributions of experiences you have about backings.Your an experimenter and that's good.I'm a user of combed flax myself to fix things on bows.
I'm wondering if you kept track of the amount or percentage of reflex that your sinewed bow kept after tillering and shot in done with TB II glue?You know there's a reason the asians don't use TB II with sinew on their horn bows.
Ed, I am hoping Hoosierf has a chance to tell us more about his successes. As for the the Asians and TB2, it almost sounds like you already know the the reason why? Can you point to the attempts you are referring to? or enlighten us further?
-
sinew is strong and has a spring like flexibility
It's the best combination of characteristics we may want on a bow back
other natural backings are usually less flexibles (vegetables fibers) or flexible but not as springy or strong
glue is the medium to keep our backing where we wants
probably an extremely solid glue wont allow sinew to flex well but hide glue is not that solid (crystallized)
I wont consider sinew putting tension on the back while drying (yes it's a feature but let's consider only finished and shootable bows)
we can put tension on any backing with reverse bracing at glue time but onl the backing with the right flexibility can take advantage of such feature
that's why I think hairs could never match sinew. they'll never spring back ad fast once tensioned
I think that it's as simple as that and that our ancestor already did all the (natural) materials tests electing sinew at first place
-
probably an extremely solid glue wont allow sinew to flex well but hide glue is not that solid (crystallized)
Good point Glis. properly matching the fiber to the matrix/resin/glue seems to be an essential requirement of composite building. Both for the proper execution of a hide glue/sinew application or any other fiber.
Perhaps there are better more well matched glues for a fiber that has different tensile qualities?
-
Of course but then you're likely going down the road of epoxy or similar for other fibers.
-
Sometimes we gotta accept the components for what they are and capable of doing and handling.Remembering what some natural materials strong and weak points are putting them in their strongest position and using them to the best of their ability.The difference in performance then is just a matter of design and tillering.There's plenty enough experimention out there yet for natural materials to not abandon ship on them quite yet.In fact technology tries to copy the strong points natural materials show to enhance their performance.I still think natural materials is the leader in that quest.For them to follow.At least for long bows & even asiatic styles.All because so many designs have been proven by expert bow makers from the past.
The compound bow is the exception though.
-
In the composite structure world natural materials are getting a renewed life now that technology has figured out ways of working around their drawbacks.
Particularly in Europe a lot of Flax and Hemp goes into automobiles.
-
Of course but then you're likely going down the road of epoxy or similar for other fibers.
Not just yet, I am hoping Ed can tell us something about Asians and TB2
-
Never seen or heard it used as a glue by them as I said earlier.There is no connection between asians and TT 3.That was my point.Personally I've never seriously considered using it with sinew.
Do you have experience with it willie?
-
You know there's a reason the asians don't use TB II with sinew on their horn bows.
I guess I misunderstood what you were saying, Ed.
No I have not tried it TB2 yet. Although TB3 worked well with some linen. PVA's are said to be susceptible to creep, but whether a matrix's is strained enough to initiate creep would depend on the glue line loads, or its interaction with the fiber used, so I can see where it might give poor results with a highly strained fiber.
As mentioned earlier, the fiber and glue probably need to be matched adequately, as sinew and hide glue seem to be. But without knowing the fiber properties in an matrix with a different glue, it might be premature to assume that epoxy or similar is required.
-
I'm loosing track of exactly what you mean.What I want from hide glue and sinew is a good snap back tensile strength on the back of a bow.The cologen in the hide glue with the sinew enhances or accomplishes this.
Titebond does'nt have that quality.In fact I think it lets the sinew take a set more so and not come back from it making the whole set up of titebond and sinew not work for it's money/be more mass inhibiting and generally be more sluggish.Or not come back near to the degree that hide glue and sinew does.Probably mimiking your shrinking testing of sinew alone which is a low percentage.
-
I'm loosing track of exactly what you mean.What I want from hide glue and sinew is a good snap back tensile strength on the back of a bow.The cologen in the hide glue with the sinew enhances or accomplishes this.
Titebond does'nt have that quality.In fact I think it lets the sinew take a set more so and not come back from it making the whole set up of titebond and sinew not work for it's money/be more mass inhibiting and generally be more sluggish.Or not come back near to the degree that hide glue and sinew does.Probably mimiking your shrinking testing of sinew alone which is a low percentage.
Ed, I am trying to learn more about uses of other glues and fibers. why they work and why they don't. Hide glue and sinew are useful as a good comparison, possibly giving insight into the underlying principles of what makes for a good glue/fiber design. I understand that you are of the opinion that Titebond may not do what hide glue does with sinew, but others have actually tried it, and it is their experience that I am hoping to look closer at. Failures in other glue/backing experiments happen for any number of reasons, just as folks have had failures with hide glue and sinew. If you know of a bow or experiment where titebond has caused more set when applied with sinew, please share more. Sinew taking set is because it got overstrained. whether it was the glue not being able to stretch enough or an other aspect of the bow is hard to determine without looking at the entire design. hoosierf did state a preference for TB2 over TB3 when used with sinew.....it makes me wonder why.
I like hide glue, and have no reason to try to find a substitute when it comes to putting sinew on a bow. The focus of this thread is......
What are your experiences with glues and backings other than sinew?
Anyone who has tried something other than sinew with hide glue is encouraged to share their experience, good or bad. There are other fibers that have a variety of working properties, and it may well be that hide glue is the best glue for them also, but I have not ruled out looking at other glues for any sinew alternatives.
-
WILLIE: I see bamboo fiber on the yarn market. Perhaps suitable for bow designs that would be difficult with a bamboo slat?
DC: "I did a little investigating(not much) a while back and what I found says that the bamboo fiber is more like a rayon making process. It didn't seem to be actual fibers from the boo. I may be wrong. :D"
I looked into this, too, and that's what I found. Even read some of the patents. Not exactly the same, but heavily dependent on chemical baths to extract the fiber. Once I laid hand on some, it wasn't as strong as quality hemp or flax.
PatM: "Before people got into reverse bracing, sinew backing was well known to cause long term reflex acquisition."
Correct. Sinew, and to a much lesser extent, rawhide, are very unlike any wood, bamboo, linen, or hemp backing, simply because they stretch much more. And, sinew both induces and holds reflex. It is known.
PatM: Extracted plant fibers are actually heavy. Also within a glue matrix they are really hard to glue so that they do not move and slip within the matrix.
Sinew is heavier per strength, but is SO much more elastic. I agree veg fibers don't seem to "take" to a matrix as well as sinew and hide glue. Bows backed with linen fabric for instance seem to take a LOT of glue to me.
-
I seem to remember long ago I wanted to raise the poundage once on a D/R KCT bow.I used 12 ply linen string.Laid down lenghtwise full length.28 strands if I recall.Think it raised the poundage 8 pounds.So every3 to 4 strands equaled about a pound of draw weight.I used smoothon epoxy for glue.Made the back almost unbreakable but no resilience of returning reflex of course.It's still shooting to this day.
-
There is another thread running currently which mentions sisal as a backing - has anyone posting here used that material? It's cheap and easy to find.
-
Ed, I am not familiar with the consistiency of smooth-on. Is it the kind of glue that you would expect full penetration into something like twine.
that seems like quite a bit of twine to add. How heavy is the draw weight on that bow? and did the addition of the linen twine create more set?