Sinew backing questions (with picts)

[dinorocks]

Another quick sinew question; how long should I wait for sinew to cure prior to completing tillering.  Note my son and I (mostly my son Colton), processed the deer leg sinew and backed a hickory bow using TBII in an effort to prevent the bow from breaking (we didn't have any real hide glue, and Colton being the primitive purest he is, was very reluctant to use the TBII)...we sinew backed the bow because there were a couple weak areas that were a result of the draw knife cutting a little too much into the sapwood when removing the bark...Colton was only 6 yrs old last year when he removed the bark to allow the bow to dry so I cannot give him too hard of a time.

We originally planned to add some snake skins over the sinew but the sinew backing project was so rewarding that we don't want to cover it up.

I have attached a couple picts to share with you.


Colton processing sinew.


Adding a layer of TBII to back of bow prior to placing sinew.  (Early Saturday morning work in PJ's)


Placing sinew.


Spreading the sinew and removing air bubbles.

Thanks,
Dino (and Colton)

[Pat B]

Very cool!   With TBIII you are still adding moisture to the wood so a few days at least for the drying. The glue/sinew will cure out in a day or so in the dry winter weather but the moisture from the glue will enter the wood and has to work it way through the wood because the TBIII has made a vapor barrier on the back.
 You should be able to tell after a few days if the bow feels mushy. If so, give it a few more days.

[Stiks-n-Strings]

Nice pics, good to see a fine young man learning the craft at an early age. Time he get's to my age he will be an awsome bowyer.

Stiks

[1oldbowguy]

Good job young man, well done to each of you.  Doesn't get much better then to pass on your sport and love to the young ones.

[shikari]

you have an excellent helper there,I am sinewing a horn composite myself today and had to stop my 4 yr old daughter from helping much to her annoyance.The only thing i fail to understand is why are you using tb3?it negates the effect the sinew and hide glue should have,the idea behind sinew backing is to give the bow the super springiness and when done with hide glue it adds reflex and speed in my humble opinion,where as when done with tb3 it does nothing other than give it a descent backing.
cheers

[dinorocks]

Hi Shikari-

If it matters, I used TB2 (Pat B above mis-read the glue type as TB3).  Either way, you probably are still correct.  I'm a novice and I have been trying to get as much info as I can from TradGang-ers...I guess you cannot always trust what your read.

Well, in hind sight (and not having any hide glue), it was still a great experience and fun working working together with my son.  Live and learn I guess....

[Pat B]

Sorry I didn't read it properly. Either TBII or TBIII can be used with sinew.   You won't get the same performance results as you will with sinew/hide glue but you will get some, plus it will give you a strong back for protection.
 PJ, looking forward to seeing your horn bow!

[macbow]

Just attended a weekend seminar with Mike Yancey. One of the questions is simular to  the above.
Mike said he uses the TB2 or TB3. Same result with either but the TB2 drys clearer vs a darker color.
Compared to hide glue his opinion is that other than being less messy no difference.
Ed Scott of Owl Bows now uses TB.

Another interesting item from the seminar was a thin layer flat across the back is good for protecting the back but gives little added benefits.
Where as a built up thick layer with the center being thicker adds all the spring effect and also causes weight changes as it gets colder.

Not my opinions straight from Mike.
Ron

[macbow]

Oh one other thing. These were for his short stressed bows.
Ron

[Art B]

All else being equal, I've never noticed any performance differencs between the different glues either. You just need to add additoinal reflex to your bow when using the TB glue. Easy to do........Art

[dinorocks]

Well, now that the sinew on the back of the bow dried for a few days, we will sand off the excess glue and sinew on the sides, although it doesn't look too sloppy.  Question:  should we leave the sinew wrapped length-wise over the tips or completely remove on the edges so wood is visible along the sides and tips...or is this a preference thing?
After day one of drying, the sinew was a little soft in the thicker areas along the center of the back and at the handle (I purposely added extra sinew at the handle because it was a bit thin)...no reflex in the bow limbs was visible.  I put the bow on a form yesterday AM and clamped lightly while it finished drying hoping to get some reflex...I removed the bow from the form a few minutes ago (after ~3 days drying) and there is a little reflex now.
I did a little internet research on using TB verse hide glue and see that there is some debate going both ways.  As I sit back and think about it, if the glue gives (i.e. stretches due to latex (?) in the glue) then I can see how the sinew might not work to its maximum efficiency (wondering out loud if "maximum efficiency" can be interpreted (in general) as the amount of reflex a bow gains?)   It seems to me that if the sinew is completely hydrated prior to applying, and applying it taunt (i.e. stretched out), it would shrink more, giving the bow a more noticeable reflex.  And, it seems logical that if the glue type used dries at the same rate as the sinew (or slower), the maximum benefit of the sinew can be achieved (i.e., if the glue dries faster than the sinew dries, maybe the sinew can be trapped in the glue before it completely shrinks).    Also, regarding my babbling above, there are probable many variables that can affect the entire process.  I was hoping not to "re-invent the wheel" but I guess it is helpful to learn by your mistakes.

[Osagetree]

COOL STUFF,, right there!!!

Keep us posted Colton  

[macbow]

One thing that Mike Yancey stressed was to get maximum effect from the sinew he soaks it in water for about 1 hour so that he is sure it is saturated. Then squeeze out the water and dip in glue.
Ron

[macbow]

Oh yes on the wrapped sinew on the tips. I've used it for making sure the ends were attached well and as decorative wraps, coloring with permanent markers.
Ron

[KellyG]

I forget in TBB I or II can't remember hide glue once I find it i will let you know but hide glue itself would cause wood to reflex. I wonder if you put it on the back and let it dry then TB and sinew. Just wondering don't mean to hijack the thread.

[Pat B]

Kelly, I don't think hide glue alone will draw a stave into reflex. It is the sinew shrinking and the hide glue that causes the reflex.

[Art B]

Tite-bond and hide glue bond very well together Kelly. I have sinewed with the TB glue over both sinew/hide glue. Worked wonderfully.......Art

[shikari]

the hide glue when used for sinewing is hot,not boiling but below boiling temp and above warm and when the sinew is soaked in this and laid on a bow it really contracts as it dries giving it the reflex.I make composites only now and everysource tells me to use only hideglue or fish bladder glue and that's what I use.
Ultimately its your bow and use what we want to.
cheers

[KellyG]

Pat I don't remember where I read it but a test was done on a strip of wood with just hide glue and it bowed as the glue dried. I will if I can find it I really dont rememeber. And I may just be plan wrong that has happened and I am sure it will happen again.
This is a good thread I mean how many is this that has kids involved and that is plan great. Hope to see more on it.
Kelly

[Art B]

I remember that article as well Kelly. The hide glue alone did reflex the slat where as the yellow glue did not.

That's not to say that you can't use the Tite-bond glue and sinew to achieve a reflexed bow. Here you just need to add the reflex to the bow before using this type of glue.......Art