Hunnic Bow ( fulldraw page 3 )

[artcher1]

Heat treating a limb can have the same effect Toomanyknots. For both procedures its a good idea to slightly convex the limbs to counter this effect.  Sinew/glue shrinks in from the sides also, not just it's length. Just flatten your limbs back out and that'll take care of your problem. Good luck.......Art

[toomanyknots]

"Just a bit of brainstorming here,but if the glue and sinew is thinner at the edges on a very thin and broad limb i can imagine something like that happening as it will dry uneven."

"Sinew/glue shrinks in from the sides also, not just it's length."

I think you guys are right. Kinda weird. But it did/does dry from the sides to the middle...

"Just flatten your limbs back out and that'll take care of your problem."

You mean something like clamping it between two pieces of wood while it drys? Because I cannot removed wood to even it out, as it is way too caved in.

EDIT: I figure if I have to ill just tiller it with sandpaper (like I was going to do anyway), I was wonder if ill have any particular problems with concaved limbs. Logic would tell me that the edges would have more stress on them then the middle of the belly, so I should probably round them a good bit... ?


 

[Lee Slikkers]

toomanyknots, where did you get the layout/plans/build for this bow?  It is an interesting undertaking and I'd love to see some more details on what the final outcome is intended to be...

Many thanks!

[toomanyknots]

"toomanyknots, where did you get the layout/plans/build for this bow?"

Well, I kinda copied the the design of this grozer horn bow, but made the limbs wider and thinner (and minus the horn belly):



I believe it's a hunnic style.

[Lee Slikkers]

Wow, that is a looker for sure!  I just picked a "book" on Horn Bows but it is a bit of a heavy read and makes me want to continue with the selfbows until I get a few more under my belt.  I would love to make something of that caliber someday.  Looking forward to seeing your progress.  Keep at it bud!

[half eye]

Toomany,
       That might be a case of the "poisen" effect. It was common in flat-wide and thin Chineese bows. Basically a thin/wide flat surface will "cup" the opposite way from the strain. So perhaps the drying sinew is allready applying enough pressure to cup your flat limbs.....the effect did not hurt the chineese bows that were so built.
     I'm not sure I spelled it right but will check on that and correct so that ya can check into it.
rich

[Justin Snyder]

Im not sure why you would put one layer of sinew on. To get any real benefit it will take a few more layers.

[ohma2]

i realy hope that works out for you,that is some extreme angle on the syahs. good luck with it.

[artcher1]

You really want to slow dry sinew at first to prevent rapid shrinking IMO. I've used wet towels on low humidity days to prevent the sinew/glue from dry out to fast, which will cause gaps between the bundles/strains.

Your sinewed back is going to add extra strain to the belly of your bow which I doubt red oak will take. To help with the cupping and added strain you could trap yours limbs really well. Hope that helps............Art

[fusizoli]

So U like Magyar  bows ..

Just some of my tought on this project, don't take it as a criticism!

The horn  bows are totally different than a wooden bow, sinew backed or not. They could take extreme bend because the sinew back and the horn belly working (the best natural materials for this) and the wooden part is in the neutral zone.

It looking a mission impossible for me. Just one way schould make it. Let the working limb longer and the siyah (we call it "szarv") shorter than now.

The sinew have to glue up toward the tips other wise the "szarv" will split of.

I would use hide or fish bladder glue next time   Two layers needs about 2-3 month of drying, 3 layers about 6 month but for the best result needs about 1 year. TB III needs the same, or more time as others have sad. I newer worked with TB glues.




Here is an old topic http://www.primitivearcher.com/smf/index.php/topic,16102.0.html

[toomanyknots]

"So U like Magyar  bows .. Grin

Just some of my tought on this project, don't take it as a criticism!'

Lol, yes, they seem to have caught my fancy sometime ago, and all criticism is always welcome! Thanks for the link too, cool thread.  This is the way I see it (which probably aint all that accurate, but here goes); I believe that this bow is pretty short, but other than that I can't see any reason rationally it would fail compression wise. The limbs are very wide and thin, as well as only "slightly" reflexed, which will all be tillered out no doubt. Even if made of a less quality wood I think it would work as there is only one layer of sinew and the limb is very wide and thin. Or at least intuition is telling me so. So I thought I'd try it. The longer siyahs or svarv's (did not know they were called that,  ) also give more draw per less limb movement the longer they are, if I had to tweek it I could make the siyahs or svarvs even longer and get as long as draw as I want with almost no limb movement, but then, performace would be not so good unless for a pretty high draw weight.

"The sinew have to glue up toward the tips other wise the "szarv" will split of."

I totally know what you are talking about, figured that out the hard way, lol. I use a glue soaked linen wrap though now and go up the siyah an inch or so in place of the sinew. Plus I make the base of the siyah fat for a inch or so before making em deep anfd narrow. This has stopped them from breaking so far. I have had success on bows up to 65#s doing it this way. I only use wood where the rings are not stressed in a way to cause a split, like plain sawn wood.

"I would use hide or fish bladder glue next time"

I would of, I just didn't have any. This is an experiment anyway, so I figure when I work out the kinks (hopefully there are none,) ill go all out on the next couple. I am so suspicious anymore of company's selling hide glue and rabbit glue as well using bones and all kinds of stuff, I like to make my own glue it just didn't work last time with this sinew I had used,.. hopefully it was because I screwed the glue up and not because the sinew is garbage. The sinew itself actually seems perfectly fine to use as a backing. I would love to get me a good source of fish glue... If titebond 3 works though I might just use it again if I don't have anything else. No cracking/semi water proof aint that bad of a thing for a sinew backing...

"Your sinewed back is going to add extra strain to the belly of your bow which I doubt red oak will take. To help with the cupping and added strain you could trap yours limbs really well. Hope that helps............Art"

True. I have seen sinew chrysal red oak... I hadn't though about trapping at all, unfortunately the limbs are already 1/4" thick. Hopefully I have made the limbs thin enough to counteract the added compression stress... 

"Im not sure why you would put one layer of sinew on. To get any real benefit it will take a few more layers."

I'd have to disagree to an extent, I use one layer alot of the time on short bows I make. I definitely get the snappyness and a little reflex with one layer. And after having a linen backed bow brake I just won't use any backing that I am not 1000% sure is not going to brake. I like the look of it too! But yes I agree with you about more layers being better to make sinew do what it does, I just don't wanna crush my bows belly.

"That might be a case of the "poisen" effect. It was common in flat-wide and thin Chinese bows. Basically a thin/wide flat surface will "cup" the opposite way from the strain. So perhaps the drying sinew is allready applying enough pressure to cup your flat limbs.....the effect did not hurt the chineese bows that were so built.
     I'm not sure I spelled it right but will check on that and correct so that ya can check into it."

That is crazy! I never heard of that till now. MAkes me kinda less worried now, hopefully it won't hurt my bow either...   

Thanks for so much advice and input guys!







 

[fusizoli]

I think the best wood for this is osage and some lighter but strong wood for szarv like elm or ash. Szarv means horn. The bow forms a big horn whan it unbraced

Good luck! Oh and buy Adam Karpowicz's book from hornbow makeing. It is a very usefull book, well worth the price it coast!

[mullet]

Using one layer of sinew and TB3 is about the same as applieing rawhide. All one layer will do is protect the back and TB3 will not shrink like Hide glue. I've glued multiple layers of sinew with TB3 and did not notice any performance increase like I did using hide glue. Just my opinion, but sinewing red oak is kinda waste of good sinew.

[artcher1]

Do a search for "poisson effect". Lots of info out there.

Eddie, don't expect the TB glue to do much reflexing for you. But you done found that out. You have to do the reflexing yourself before appling the sinew/TB glue. Other than that, I've haven't found that much difference between the different glues. Hide glue I would give an advantage to in warmer weather and the advantage to the TB glue in colder climates.

When you talk about the added performance you get from extra layers of sinew, I got to ask, for what day, at what temperature and at what humidity level. One layer for a backing is just fine in my book. Adds physical weight for stability to an already too light short bow. Less stress on weaker compression woods. Big confidence booster when shooting the bow, and that's very important for the type bows we build. The list goes on and on.

Well, at least for my perspective, I look at sinew as a great backing material. All the other benefits are just pluses.........Art

[mullet]

Art;

I've only sinew backed Osage and Mulberry. One short, Plains style bow I backed with three layers of sinew with TB3. I could pull this 48" bow 28" but the cast was real poor. I really think that the sinew, with the stretchy TB3, kinda, overpowered the wood, and made it respond slower. This Little bow had no string follow after unstringing it. The bows I have  sinew backed with  hide glue have to be tillered periodictally and after sitting in the sun for awhile,(90 dgs, 65% hum.) just seen to zip an arrow quicker. It just seemed like the limbs recovered a lot faster.

I have to agree, I'd rather use sinew to back a bow than rawhide, or other material. I think with the right glue, one layer of sinew, you just get a little more added benefit.

I also know you have to induce the curves when using TB, but a sinewed backed bow with a natural glue will eventually pull itself inside out from shrinkage.