Primitive Archer
Main Discussion Area => Bows => Topic started by: PEARL DRUMS on February 11, 2014, 10:02:03 am
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Lets discuss the finer points of sinew. Here are a few of my thoughts:
1. 3 year old, open air stored sinew is cured before I ever use it.
2. Dry is dry
3. Prove to me with numbers, and not ancient Japanese proverbs why waiting (x) amount of months is crucial.
4. Glue quality maybe?
If a sinewed bow is rock hard and dry after a month or two, why wait six more months? Around here my sinew could dry, rehydrate and dry again in six months with all the humidity changes we get. It can go from 25% to 70% rather quickly totally undoing any drying done in prior months.
So what are your thoughts? Lets not argue, rather share thoughts or even hard numbers. This topic has always interested me and I feel a lot of info is just passed on with no real regard to the "why's".
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I'm interested also...
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eondering the same thing ???
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I've never thought about it in those terms but would think once it was dry enough to separate that it could be used at any time thereafter. :-\ Am also wondering if it may not be better using it as fresh as possible allowing any further seasoning or curing to be done in it's final resting place.
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Pearl
Maybe sinew is like a dry stave. What would you rather have. A dry Osage stave or a dry and "Seasoned OSAGE STAVE".
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Dry is fine for me Dean. Its all good in my book.
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<snip>What would you rather have. A dry Osage stave or a dry and "Seasoned OSAGE STAVE".
Whichever I can get under my drawknife first...
OneBow
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When I see that the glue is dry I shoot it. Hide glue takes longer then Tightbond to cure so I let it sit till it is glassy looking and hard.
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I've never thought about it in those terms but would think once it was dry enough to separate that it could be used at any time thereafter. :-\ Am also wondering if it may not be better using it as fresh as possible allowing any further seasoning or curing to be done in it's final resting place.
Green sinew would probably rot/mildew on the bow Freddy
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The rate at which sinew dries is roughly 1 -2 weeks for a 1mm thick layer. If you allow your sinew to dry for this time between layers and only apply 1mm thick layers then it will be dry pretty quickly. I like to do all my bows like this.
The problem is if the underlying layers aren't left to dry before adding a new layer the drying times rises with the square of the thickness. Or 1mm - 1 week, 2mm - 4 weeks, 3mm - 9 weeks, 4mm - 16 weeks.
Also when you apply a fresh layer to dried sinew then that lowe layer will absorb some of the moisture from the fresh layer which leads to longer drying times than you might think.
As for does leaving it for years and years really help.....has anybody here got the inclination to make a large selection of different sinew backed bows, leave some for the minimum safe drying time and the rest for say 3 years as the old Turkish flight bowyers did........then tiller them all flawlessly and do some rigorous completely unbiased testing?? If not then I guess all we've got is that they did it in the past and logic tells you that they wouldn't have done it if there was no benefit. Bearing in mind that back when the Turkish were making these hornbows en masse the methods used would have been the ones perfected over many hundereds of years.
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That's just it Mike. Lots of things done in the past don't hold nearly the water now. Im not arguing any points you've made, just conversing is all.
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<snip>If not then I guess all we've got is that they did it in the past and logic tells you that they wouldn't have done it if there was no benefit. Bearing in mind that back when the Turkish were making these hornbows en masse the methods used would have been the ones perfected over many hundereds of years.
Uhmmm... actually logic tells us no such thing. We could surmise that there may have been some reason for the this practice that was based upon scientific observations and sound engineering, but it certainly does not follow merely from the demands of logic that such was the case. Any of a thousand explanations might explain the same behavior as well or better than the sound and reasonable engineering theory. Magic, superstition, tradition, practical demands of mass production, or any number of other ideas could readily have caused the exact same practice. I mean, it's farfetched, but it could even have been that there was a higher tax rate on finished bows than bows that were in the process of being made. So perhaps they delayed finishing them till they had a buyer to pay the taxes.
The 7 most powerful words to blockade any kind of progress are "That's the way we've always done it." Ancient peoples were not less subject to the power of those words than we are today. In fact, I'd postulate that they were likely far more impeded by their power than are we.
Not all sunken chests have a bottom lined with gold doubloons, ...some just have old dead sailors wet socks in them. Just because an idea is old and hidden in a veil of mystery, does NOT mean it is the best or better idea. Logic certainly does not imply such. Logic only tells us that there was a reason, and perhaps several reasons, but it does not require that the reasons were good ones.
OneBow
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I've only made a few sinewed bows and have given each layer(usually 2 or 3) a month or so to dry(cure, season) so that is all I know personally. I've seen the different processes of some of James Parkers Asiatic horn bows. James gives his bows about a year I believe to cure. You can see the bow's reflex increase until the limb tips pass each other over that time making me think the sinew/hide glue continues to cure. The ancient Chinese gave their horn bows 10 years sometimes but if their bows failed the bowyer suffered. ;)
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Pat I add so much reflex at glue up that none of my bows have ever changed after a few weeks of drying. None have gained any reflex and none of the tillers have changed. I think a lot boils down to proper amounts of hide glue, proper humidity when the job is done and proper amounts of sinew.
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Always wondered this myself. One thing that I have thought is that people did not have the controlled environment like we do. Their work was probably subjected to the elements more than ours. We have the ability to constantly move air along with regulate temp and humidity. Also they probably had more hours in it than we do with modern tools so the simple/stupid way was to leave it alone. Plus I don't think hard numbers were more important than traditional values in ancient society. I could be totally wrong but that's what I think.
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(http://i1181.photobucket.com/albums/x436/blackhawk28/Mobile%20Uploads/Child_eating_popcorn.jpg) (http://s1181.photobucket.com/user/blackhawk28/media/Mobile%20Uploads/Child_eating_popcorn.jpg.html)
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I have built three sinew backed bows. Each has just one relatively thick layer of sinew on it.
The first two I only let dry for one week before final tillering.
The last one I let dry for 1 year because I more or less forgot about it.
I didn't notice any difference between the three.
Patrick
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I love where this is going.
Good thoughts Pauly, great personal feedback Patrick.
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I think I'll check the weight of "Lil Thumper", the 56" sinew backed osage static I recently built. I haven't shot her in over a month and it has been pretty dry here plus she in inside where our wood stove dries the air more. I shall return...
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...just braced her up and walked down to the basement and put her on the tree, no exercising first. Today she pulled 58.80# an increase of about 2.5# and 3# over what she was when I finished her. A few pounds difference could be explained by R/H changes.
If you remember, I sinewed this bow during warm, very wet conditions(40" of rain in 3 months). That is why I let her rest longer after the sinewing was completed so I was sure the sinew/hide glue was dry.
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From all of the other responses I'm figuring I must have misunderstood the original questions ???
It sounded to me like you were asking whether or not the sinew itself needed to dry and age before attempting to use it on a bow back or other intended project?
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That's good info Pat. I see more info that leans towards dry being good enough.
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Fred, even though I've never done it I think you can use fresh sinew for bow backing. We use green(fresh) snake skins over our bow backs sometimes without problems. As long as the sinew and hide glue dry together I see no problems using fresh sinew.
Pearlie, I think as long as the sinew/hide glue is dry and the wood has dried from absorbing moisture from the sinewing process the backing should be stable enough to be consistent.
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Here is another tough one to chew on:
Most will tell you to wait at least 2-3 months. But the difference where Im at between June through August and December through February are two totally different animals. Both fall in the 2-3 month minimum wait time, but they vary by at least 30-40% humidity.
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Our R/H varies here as much also from summer to winter. Our R/H now is 30% and it is snowing and 31 degs.
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This is why composites had processes done according to the season. Much of the time was likely devoted to waiting until the next correct season came around.
I see no difference in performance in a bow dried "enough" or cured for a year.
Many guys on ATARN patiently wait a year and no special performances have been noted by any of those bows.
Adam Karpowicz has made some great heavy weight bows that have been cured a long time but he also slapped together one in 6 weeks and it seemed to perform in similar fashion.
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We've learned from other experiences that wood dries at a rate of about 1" per year in general. I'm sure some woods dry faster than others. Has anyone done a test to see how long it takes sinew/hide glue to dry.
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No tests here Pat. But I check on my sinew jobs almost daily when I do one up. It seems to me if done in the proper season, after a week to ten days its hard as rock and cant be dented with a thumb nail. Not exactly scientific, I know!
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Kool Thread...
I've read Mr. Karpowicz's book...
In it he mentions a Sultan or some such being killed by a Bow Malfunction...
You know everyone that touched that bow in its making got A Hair Cut...
I think you had it cutting both ways.
You can't Work in a Medium for a Thousand Plus Years and Not know it Well...
Then again Technology was So Tightly Guarded by Masters and Guilds...
There was very little, if any, free exchange or comparison of ideas.
Heck coming up with a Radical New Idea very well could get you burned at the Stake...
-gus
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Look how much wood bow building info has changed just since TBBI came out. I have no doubt we could change curing time info for sinew backed bows as well with folks experimenting with the process(s), just like with wood bow building.
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That very thought is what prompted me to start this thread Pat.
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Another thing to think about.... 50% humidity at 30 deg is not the same as 50% humidity at 80 deg. Cold air does not hold moisture like hot air. So with that comparison at 30 deg the amount of water in the air would be much less.
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No tests here Pat. But I check on my sinew jobs almost daily when I do one up. It seems to me if done in the proper season, after a week to ten days its hard as rock and cant be dented with a thumb nail. Not exactly scientific, I know!
Actually i think you are more scientific than you think, more observatory but thats one was to conduct science.
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The difference I have found is that a bow that has had the sinew cured rather than just simply dried is more stable once finished tillered. A bow that is tillered with just dried sinew will have the tiller change over time.
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I only have attempted one sinew backed bow, and still working on it. The osage stave was three years old and stayed in the house, with heat and air conditioning and we very seldom open windows. I did the bow build in 17 to 25% RH and when it was time to sinew the RH was 18 - 20% the hole time. After about a week I noticed stress cracks in the belly and it gained a little reflex. After three weeks the bow had not gained any more reflex and the sinew/glue was hard as a rock. Finished the tiller and now have shot it about 250 times. I have taken FD pictures after almost every shooting session and the tiller seams to be changing each time.
With only this one experience, I'm leaning towards Marc's comment.
The difference I have found is that a bow that has had the sinew cured rather than just simply dried is more stable once finished tillered. A bow that is tillered with just dried sinew will have the tiller change over time.
I have not been doing anything to the tiller each time just shooting and hoping that the tiller will stay the same at some point then I guess I would do the final/finish tiller. Maybe I should have waited a few more months. Time might tell me on my first build and I can improve on the next and the next and the next. Experience can tell the story........If you listen. :) ;)
DBar
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The difference I have found is that a bow that has had the sinew cured rather than just simply dried is more stable once finished tillered. A bow that is tillered with just dried sinew will have the tiller change over time.
I have had to retiller a friends sinew/osage bow twice over a 20 year period. It keeps gaining weight and he can't string it.
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Sometimes the "weight gain" of a bow over 20 years is a loss of strength of the owner ;)
I think Marc may be talking about going out of tiller rather than an increase in draw weight.
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Not to add more complexity to an already complex question, but another issue that underlies the dried versus seasoned sinew debate is how much glue there is in the sinew/glue matrix. It seems that if one were to add a lot more glue relative to sinew, the collagen in the glue might be oxidizing, polymerizing or chemically changing in some other fashion over a longer period of time, and it might absorb and release water at a different rate than the sinew and wood. On the other hand, if the bow maker added just barely enough glue to get the sinew fibers bonded to the wood and to each other, that would create a very different dynamic within the backing over time.
The sinew fibers might also change chemically over time, as there's non-fibrous (non-collagen) tissue within a tendon much like what people find within a deer hide and remove by bucking (soaking in an alkaline solution, usually wood ash) and then acidifying (soaking in an acid solution, usually diluted vinegar). Maybe there's value in letting some of these non-fibrous tissues degrade, leaving just the collagen? Come to think of it, has anyone ever tried treating sinew like a hide before using it to back a bow? As in bucking and then acidifying it so as to remove non-collagen tissues?
As someone who processes a lot of sinew, I've definitely noticed that back tendons that are dried and stored for a couple years are much easier to separate into individual fibers. I have some really long pieces I've been saving that are about 3 years old, and they have a different consistency and feel in the hand than the ones I cleaned and dried just this past fall. Does this mean they'll make a better bow backing? My instinct says yes, just because of how they feel, but I won't know that until I make otherwise identical bows and back one with old sinew and the other with new. I don't have two staves that could yield identical bows at the moment, so I'm not in a good position to do this experiment.
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The vast majority of dry tendon is collagen or elastin. Approaching 90%. The rest surely is barely worth getting rid of. Washing the tendon well probably gets rid of any readily soluble stuff.
I can't really see any point to adding extra glue. Hard to see how that would add any better stretch/elastic quality.
I reduce the glue in my backings to the absolute minimum.
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<snip>If not then I guess all we've got is that they did it in the past and logic tells you that they wouldn't have done it if there was no benefit. Bearing in mind that back when the Turkish were making these hornbows en masse the methods used would have been the ones perfected over many hundereds of years.
Uhmmm... actually logic tells us no such thing. We could surmise that there may have been some reason for the this practice that was based upon scientific observations and sound engineering, but it certainly does not follow merely from the demands of logic that such was the case. Any of a thousand explanations might explain the same behavior as well or better than the sound and reasonable engineering theory. Magic, superstition, tradition, practical demands of mass production, or any number of other ideas could readily have caused the exact same practice. I mean, it's farfetched, but it could even have been that there was a higher tax rate on finished bows than bows that were in the process of being made. So perhaps they delayed finishing them till they had a buyer to pay the taxes.
The 7 most powerful words to blockade any kind of progress are "That's the way we've always done it." Ancient peoples were not less subject to the power of those words than we are today. In fact, I'd postulate that they were likely far more impeded by their power than are we.
Not all sunken chests have a bottom lined with gold doubloons, ...some just have old dead sailors wet socks in them. Just because an idea is old and hidden in a veil of mystery, does NOT mean it is the best or better idea. Logic certainly does not imply such. Logic only tells us that there was a reason, and perhaps several reasons, but it does not require that the reasons were good ones.
OneBow
I have to say that you are missing my point rather...
Read Adam Karpowzi's book. Then do some research into the distances achieved by the Turkish flight archers. There are rather large stones planted in the ground at the place where the record distance arrows landed. They are still there!
925 yds is quite a shot.
When somebody comes close to that again i'd like to talk to them!
I don't agree that the bowyers of old were stuck to the mentality of 'that's how it's always been done' Look at a Turkish bow and then tell me that that design was arrived at and then stuck to doggedly....If poeple were stuck in this way of thinking then NOTHING would ever be invented....
When did I say that sunken chests were full of dubloons?
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That's just it Mike. Lots of things done in the past don't hold nearly the water now. Im not arguing any points you've made, just conversing is all.
Ah but many more do than don't!
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We've learned from other experiences that wood dries at a rate of about 1" per year in general. I'm sure some woods dry faster than others. Has anyone done a test to see how long it takes sinew/hide glue to dry.
Look at my first answer on page 1 ;)
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Sometimes the "weight gain" of a bow over 20 years is a loss of strength of the owner ;)
I think Marc may be talking about going out of tiller rather than an increase in draw weight.
By definition they are the same thing?
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After reading all this I feel fortunate than none of my sinewed bows have changed enough to notice, I only have 2 in my possession still, but haven't got any negative feedback on the others that are out and about. Not sure why Im the lucky one? Im starting to lean towards glue quality and QUANITY playing a huge roll. Also, Eric's spin on older sinew is the same as mine. I have some "Gus" sent me maybe 3 years ago? Its what I recently used on a yew bow and is like angel hair after some work. Also, I leave very little glue in the sinew. Just enough to stick down and blend in. I think 2 months is the longest Ive ever waited on sinew.
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The difference I have found is that a bow that has had the sinew cured rather than just simply dried is more stable once finished tillered. A bow that is tillered with just dried sinew will have the tiller change over time.
+1
All it took was once for me to find this out and learn my lesson..so I now wait...besides what's the rush? This isn't a race....better safe than sorry in my book,and just wait it out.... ;)
Screw sinew anyways,its overrated 8)
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The Massey Medicine Bow I built a while back had the most drastic changes of any other sinew backed bow I've built, which isn't many. That bow is sinew backed hickory with a rawhide covering. The draw weight of that bow has gone from 55# to 45# and up to 65# all depending on the R/H. The tiller didn't change and the bow still shoots OK but when the humidity is high this bow becomes a noodle.
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I think there are things about Sinew Backed Bows that we are just now starting to learn.
Pat B's last post..... Some wood/sinew combonations may not work as well as others.
Hickory absorbs moisture far faster than Osage. Could it be that this new moisture soaks right into the sinew far faster and effects the tiller. Something to think about.
Something else. Eric sort of hit on this. Many of the strongest glues form molecular bonds with the materials they are supposed to hold torether and within the glue itself. Cant say that I know how long it takes for most of those bonds to be made. Cant say that I know if the bond making stops when the moisture is gone.... Could be that it continues for quite some time.
David
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David, when I built this bow I was copying the last bow Jay Massey built before he died from a hickory tree at his dead brother's house. Jay also had a rawhide covering over the sinew. All the components, hickory, sinew, hid glue and rawhide are hygroscopic meaning they take on and release moisture to the atmosphere as the R/H changes. Knowing this, I gave this bow a good coat of Massey finish, 3 or 4 coats of Tru-Oil and spray satin poly thinking it would at least slow the hygroscopic rate but I learned a good lesson about R/H and it's effects on wood bows.
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Screw sinew anyways,its overrated 8)
I snickered when I saw this, but I have no choice but to agree with you for most bows, especially for modern wood bows that tend to be over 60 inches in length. Sinew works magic when laid on woods that are compression strong and not too dense, like yew, juniper and eastern red cedar (which is actually a juniper, not sure why we keep calling it a cedar). It seems to add modest benefits to heat treated elm, white ash and eastern hophornbeam, and marginal benefits to osage when you can actually get it to stick. Other woods... meh.
I'm also amazed at how long of bows people will try to sinew back. Anything over 55 inches just doesn't seem worth it to me. Sinew adds too much weight per unit strength, even when you absolutely minimize the amount of glue in the backing. I'll sinew back short bows, but anything over 55 inches either gets a rawhide backing or some sort of fabric. I just had a gentleman ask about buying several ounces of sinew to back a bunch of 60+ inch hickory bows. I talked him out if it. The time spent sinew backing those bows just wouldn't have yielded a good return on investment, in my opinion.
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Sometimes the "weight gain" of a bow over 20 years is a loss of strength of the owner ;)
I think Marc may be talking about going out of tiller rather than an increase in draw weight.
By definition they are the same thing?
The tiller definition? No. Marc refers to tiller changing and PatB refers to "tillering" the bow to a reduced weight due to the bow gaining weight.
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55" cant cover all draw lengths. The person pulling 29 or 30" may full well benefit from sinewing a 60-62" bow.
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I've only had it drastically change on me once. I would of sworn the sinew was dry after five weeks. I tillered it to 60# and finished it out. I shipped it out and it sat a couple of weeks before the new owner shot it. It had gained ten pounds. I suspect there was still some moisture in the wood from sinewing it, but that's just a guess. Whatever happened, it was a bit embarrassing. I give sinew an extra month of drying time before tillering now. Josh
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I don't wait more than 2 months with wood bows. I suspect that the long wait has more to do with horn bows. Once you have the horn glued down onto the wood core it acts quite a bit like a moisture barrier so when the sinew is applied all the moisture from that gets absorbed by the wood and as the sinew dries it also locks moisture inside, double whammy.
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55" cant cover all draw lengths. The person pulling 29 or 30" may full well benefit from sinewing a 60-62" bow.
The person drawing 29 or 30 inches might benefit from having their bow backed, but I'm not sure they'd benefit from having their bow backed with sinew. I'd probably go with rawhide or fabric instead. But that's just me, and I don't pretend to be infallible.
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Rawhide and fabric don't have an potential to DO any work though. Sinew is magic on a bow when you use it to go beyond the 2:1 bow to draw ratio. Particularly when there is only sinew on the actual bending portions.
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Rawhide and fabric don't have an potential to DO any work though. Sinew is magic on a bow when you use it to go beyond the 2:1 bow to draw ratio. Particularly when there is only sinew on the actual bending portions.
This sounds very peculiar to me. Are you claiming that rawhide and fabric, which both add mass to a bow, don't offer any resistance to bending when applied to a bow's back and therefore shoulder none of the 'work' of the bending portion of the limbs?
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Cant answer for PatM, but my answer is no. Rawhide nor fabric add any noticeable bend resistance. Protection from splinters? Heck yes!
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Like PD says. Try measuring the draw weight of a bow and then adding rawhide or cloth and compare again.
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Eric I think you might have missed the point that Pearly was making. When it comes to bows, short is a relative term. For a 26" draw, 60" is not short, but for 30" draw 60" is relatively short. The idea of sinew's weight being a disadvantage on longer bows is based on the premise that it's not being worked hard enough to achieve efficiency. Relatively speaking, sinew would be earning its keep on a 70" bow IF the draw length was 35" or better. Conversely, sinew would not be optimal on a 50" bow IF the draw was only 20". I hope that makes sense. :) Josh
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I tend to think that seasoned sinew backed bows are less affected by Relative humidity changes than a newly finished sinew-backed bow. Seasoning = stabilizing. I dont just mean stable in terms of the tiller walking around on you as it continues to dry, but that it is less likely to react dramatically to exposure to higher RH. Just a hunch.
Keep in mind there were waterproofing additives often used with hide glue that might have extended the drying time.
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Eric I think you might have missed the point that Pearly was making. When it comes to bows, short is a relative term...
I think I get what he's trying to say now. Thanks!
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If the question is about a all wood bow with 2-3 layers of sinew, not very wide, not a huge amount of reflex, and with a draw of about 1/2 the length of the bow. Then there is no reason to let the sinew season for more than a month(not that it would hurt). The reason the turks let them season for a year+ is that these bows were under a huge amount of strain with a large layers of sinew. When you are starting to bend a bow with the tips touching with reflex and ending with a bow that has a extreme overdraw then we need to look at using only the best glues with the perfect setup time and allowing the collagen to form complex bonds over months. I feel I have done my fair share of experimenting with sinew. I've made juniper and cedar(incense cedar not erc) bows with 5-7 layers of sinew. Sometimes shooting in only two weeks. Yes the tiller changed in time but the reflex just continued to grow. I didn't become obsessed with good glue and seasoning time till I started making horn/sinew only bows that are 50% horn and 50% sinew on average. The sinew would draw the bow into a reflex as high as the bow was long. A O shape missing the top. I would start to bend and tiller the bows after 2 months of dry time. Plenty of time for the complex glue bonds to form. The problem was I would still be tillering this same bow with heat and sand paper 3 months later. If I wait 6-8 months, when it's tillered it's done. This is a different game. If you are asking about a 52" wood bow with 2 layers of sinew that you will be drawing 26", then by all means go ahead and shoot it after 3 weeks
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Thanks for all the feedback Chuck. This was a good thread.
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One thing I notice is that no matter how long people let their sinew cure it still gets that "hammered" look after the bow starts bending. This must be from the glue microfracturing due to the glue bonds failing.
I wonder exactly how complex these bonds are actually becoming if after months the glue is still failing to a degree and only the sinew is actually in any degree of continuity.
I have been experimenting with a few ideas to try to get the glue to hold up better under this stress where it still appears clear after bending. Just time doesn't seem to be the answer.
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Pat Ive made 8-10 sinewed bows and none have ever taken on that hammered or cracked look you speak of. Ive never even heard a crack or pop once I start bending the bow? I contribute that to the glue quality and quanity. I leave very little glue behind.
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I think that is a large part of achieving that. Good glue and less of it.
Where do you normally let your bows cure/dry and at what temperature?
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62-64 degree's, 25-35% humidity. I usually have a 3-4 month window to sinew bows. If I miss it, I wait a year. I tried sinewing a bow in 60-70% humidity and it mildewed fast. I have a quanity of glue and back straps Ive used for all of these bows. Its nice knowing the materials are the same and the results have been as well.
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I've never had the scary popping sound on any of my sinew backed bows but I squeegee most of the glue off of the sinew before I lay it down. I do sometimes add a thin layer of glue over the sinew after it is all down but that is mainly to smooth out the surface.
I usually store a freshly sinewed bow in our utility room over the hot water heater to cure. The utility room is slightly cooler than the rest of the house and there is good air circulation near the gas hot water heater. Inside of our house is quite dry during the winter. This past summer when I built my last sinewed bow was the wettest summer we've had in a long time with over 40" of rain in June, July and August. That is one reason I allowed about 3 months before stressing the bow.
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I've only had one sinew-backed bow, out of perhaps a dozen, develop that 'hammered' look and thinking back it was because I used way too much glue. Now I squeegee as much glue out of the sinew before I lay it down as I can, and remove more glue by heating the backing and pressing it with cloth. I also use sinew glue that I make myself the same day I'm laying down a backing, and monitor the glue's temperature so as to minimize denaturing the collagen in the glue.
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By definition they are the same thing?
The tiller definition? No. Marc refers to tiller changing and PatB refers to "tillering" the bow to a reduced weight due to the bow gaining weight.
The same thing as in the woods properties have changed. If the tiller changes - something has changed. If the bow gains weight - something has changed. What you call the process of getting it back to where you want is immaterial.
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Your question was kind of vague and I wasn't sure what you were getting at.
I wouldn't call weight gain a change in tiller or a change in the property of the wood.
I was merely trying to narrow down what Marc meant since he wasn't clear.
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This is some Good Stuff y'all...
After reading through this Thread a couple times.
I realize the only part that I have any first hand knowledge of is in Processing Green Sinew.
And now I find myself wondering if the way the sinew is cleaned can have an effect.
I usually Clean and Dry my sinew in One Gallon Bag size batches.
Process as follows:
Thaw a Gallon Bag of Back Sinew.
Scrape each piece as clean as I can of Meat.
As each piece is finished I drop it into a pot of water with Dawn Dish Soap to soak.
When the batch is scraped and in the Soap and Water Soak I wash it vigorously changing soap and water several times.
Once the water runs clean, I fill the pot with fresh soap and water, cover and place in the Fridge.
I then wash and rinse at least once per day for three to five days.
When I'm happy with the Color and Smell of the Sinew, I hang it to dry.
I let it hang for three to five days or until fully dry.
During the wash - rinse cycles most if not all of the Slippery Membrane is removed.
And at each washing I wash and rinse till the water runs clear...
Just Food for Thought...
-gus
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Hi Gus, I use a generally similar method for cleaning back tendons, although I scrape the membrane off when I scrape the meat off the other side, and I dry sinew on parchment paper under a fan rather than letting it air dry while hanging. Not sure that either of these differences matters that much. Getting that membrane off makes the sinew much easier to separate into fibers though.
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When I said changing tiller I didn't mean draw weight change, that is mostly due to moisture change in the bow. No if a sinewed bow that has not been left to cure properly is tillered out and then left sitting for several months it will have issues with the bow going out of tiller. Anyone else have this happen?
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I've had this happen on earlier bows where I ended up with too much glue in the sinew-glue matrix. I suppose it could be due to sinew curing, but I've always assumed it was because the glue was still drying and that I had used more glue on some parts of the bow than on others, yielding a changing density of the backing matrix. But I admit I never thought to study it too closely, so I could be misinterpreting what was going on. I haven't had this happen in the last several bows I've made, as I'm a lot more careful now about minimizing the amount of glue I use.