Primitive Archer

Main Discussion Area => Bows => Topic started by: knightd on October 30, 2008, 11:46:43 am

Title: Sinew??
Post by: knightd on October 30, 2008, 11:46:43 am
OK just wanted to get some feed back from you guy's on laying down sinew..
I put one course down and wait for a few days then put down the next so on so forth. But have heard of allot of guy's just putting down all 3 or ever how many you going to use all at the same time. I would like to know if any of you guy's do this and how did it work out compaired to one at a time..
Title: Re: Sinew??
Post by: Pappy on October 30, 2008, 11:52:36 am
The few I have done I put it down one right behind the other,it worked out fine.Put
 it in the hot box for a couple of weeks and finished tillering.
   Pappy
Title: Re: Sinew??
Post by: JackCrafty on October 30, 2008, 12:11:25 pm
Putting it all on at once is like applying a thick coat of paint.....it dries unevenly.  One of the tricky parts about sinew is getting it to dry and cure without self destructing.  It will crack, warp, pull away from the wood, and may even crack the wood.  Damp sinew will behave itself, but you don't want damp sinew on the back of a bow.

If you look at sinewed bows from history, I think you'll find that the thicker the sinew, the shorter the bow.....or at least the shorter the working area.  Longer bows do not benefit much from thick layers of sinew.

Personally, I prefer to apply thin layers of sinew.  One, maybe two applications.  I usually wait a week between layers.
Title: Re: Sinew??
Post by: knightd on October 30, 2008, 12:29:05 pm
I normally put down 2 layers and then 1 just down the center.. I process the sinew down real thin..
 I'm open to all the input I can get..
Title: Re: Sinew??
Post by: JackCrafty on October 30, 2008, 12:57:38 pm
Hmmm...you're making a narrow center strip of sinew do most of the work?  I'm not sure you'll see good performance from the sinew that way.  I dunno.  Sinew stretches a lot, so you'll get good flexibility, but I think you'll loose the "snappy" effect.
Title: Re: Sinew??
Post by: Justin Snyder on October 30, 2008, 01:21:38 pm
I have done it both ways and I liked adding it all at once.  The surface is not perfectly smooth and when I put on one course and let it dry it got little tiny air bubbles under the second course. Put all of it on and set it in a controlled environment where it wont dry to fast and you get a better finish. I put mine in a cool dark closet for a week, then get it out and let it finish curing.  Justin
Title: Re: Sinew??
Post by: knightd on October 30, 2008, 01:32:11 pm
Sounds like I might try just puting it all down at one time..

Jackcrafty.. It all would be working just the last corse is narrower.. well it is really tapered from the handle to the tip. Just staying inside of the outer edge of the limb.
Title: Re: Sinew??
Post by: Badger on October 30, 2008, 02:05:32 pm
I normaly do  thin layers about 2 days apart in dry weather. Something I have been considering doing is to sinew a hickory backing strip pulled into very heavy reflex and then glueing it to a bow after the fact. Sinew can stretch up to about 10% and we normaly only work it slightly over about 1%. Steve
Title: Re: Sinew??
Post by: Pat B on October 30, 2008, 03:09:05 pm
On the few sinew backed bows I've done I would add a layer of sinew, let it rest for a month and add another, wait a month and add the last layer to even out the irregularities. Then I would let everything dry for a month and add snake skins with TBIII and after a week add a thin layer of TBIII over the whole backing before adding the finish. Pat
Title: Re: Sinew??
Post by: Hillbilly on October 30, 2008, 04:36:15 pm
I haven't made many sinewed bows, but the ones I did, I followed Jim Hamm and Reginald Laubin and just stuck it all on there at once. Worked fine, as far as I can tell, but did take a while to dry out.
Title: Re: Sinew??
Post by: JW_Halverson on October 30, 2008, 04:57:02 pm
My first few sinewed bows looked like horrible scar tissue but they worked fine.  I did all the courses at once. 

Then I  got the idea of wetting the bundles in the hide glue, laying them out straight on a piece of glass and combing them out with a fine tooth barbers comb to take out all the snarls and twists.  Comb from the middle out to either end while holding the sinew down against the glass.  This oriented the strands nicely, then I would lift up the bundle that was now shaped like a piece of tape and laid it out on the bow. 

I still lay up the two or three courses at once and the backs are nicely smooth.  I've found that there tend to be fewer sections of the limbs that need much tillering afterwards.  I believe you get more consistent thickness along the limb this way. 

Good luck with your project.
Title: Re: Sinew??
Post by: knightd on October 30, 2008, 05:12:12 pm
Thanks guys..I got a few bows to sinew back.. so puting down all the corses down at once will help in getting them done somtime before this time next year.. :D..
Title: Re: Sinew??
Post by: Pappy on October 31, 2008, 06:39:48 am
I also wrap them with an ace bandage ,you would think the glue would stick to it but
it don't much.I will wrap it and leave about a day and the carefully unwrap,it will really smooth the sinew out and make it lay flat.Then let it dry for a couple of weeks and go at it. :)
     Pappy
Title: Re: Sinew??
Post by: Marc St Louis on October 31, 2008, 08:16:03 am
Most all the sinewed bows I have made I laid down the sinew all at once and most of it down the middle of the limb.  I will lay up to 4 or 5 courses down the middle but the edges only get 1 course.  This keeps the mass of the bow down and makes the sinew work harder

That idea of yours sounds interesting Steve.  I usually reflex my bows several inches before sinewing
Title: Re: Sinew??
Post by: YewArcher on October 31, 2008, 08:23:22 am
I do mine all at once. With practice and care you can get it pretty even. I agree with the center of the bow idea. The heaviest sinew should be concentrated at the center of the limb and through the working portions. My edges typically get one coures and as i aproach the tips I fade it real thin. I have done it both ways though and do not really see a differnce in the end product.....except that you can get a bit of a smoother finish as laying over dry sinew really lets you fill in the small voids.......butif you do a good job while laying all layers you will not have anyy voids. Its the same thing with dry time. I ahve not noticed any differnce in bows that have cured in two weeks or 3 months, they all end up about the same. The 3 month cures llok impressive becuse they pull into more reflex but after tillering they end up about the same.

Steve
Title: Re: Sinew??
Post by: knightd on October 31, 2008, 08:50:05 am
The only bad thing ive heard is sometimes when puting them down at diferent times some people have had them lift. Most all of the bows I have sinewed have been short recurves..I'm kinda wandering what kind of benifits I will get by puting sinew on some of the longer bows?
Title: Re: Sinew??
Post by: JW_Halverson on November 03, 2008, 01:24:39 pm
I've never sinewed a longbow, but I have asked several people that have a great deal more experience how well it would work.  The concensus is that you shouldn't waste the sinew on longer bows.  On longer bows the limb doesn't get a deep enough bend to really "load" the sinew and all it does is add weight to the limb and reduce cast. 

The rule of thumb I was given for stiff handle bows was to double the draw length and add 10% (example: [26" x 2] + 5.2" = 57.2")  Anything shorter than that will improve with sinew, everything above that will suffer from the treatment.  For bend in the handle, just double the draw length without adding the 10% (example: 26 x 2 = 52" ). 

Your mileage may vary, subject to state and local taxes, batteries not included.
Title: Re: Sinew??
Post by: knightd on November 03, 2008, 04:47:20 pm
Your mileage may vary, subject to state and local taxes, batteries not included.. :D...

Yeah I think I should have said longer  as in 60" 62" or so..lol..