Gorilla glue?

[Newindian]

Had some in the garage went and looked at it ( wood glue),pulled off a dryed piece and found it could stretch to about twice it's length then shrink Down to its original length. This would make it desirable as a glue for sinew backings right  ?

[Pat B]

When I do sinew backed bows I use hide glue. I know some use TBIII but I've not heard of anyone using Gorilla Glue. Give it a try on a test piece of wood.

[JW_Halverson]

There is a post on here that linked to an article where a shop tested many different common woodworking glues.  They lab tested the same joint using several different woods and the different glues.   Gorrilla Glue, "The Toughest On The Planet" so the manufacturer claims on their package, performed significantly worse than ALL other contenders.  Not exactly a ringing endorsement.

And since Gorilla Glue "foams" when in contact with moisture I would say it would be an abject failure with the sinew.  The idea of using hide glue is that the two materials molecularly bond with each other creating a magnificently homogenous material. 

The stretchy feature of the glue piece you found actually works against the engineering principal of a sinew backing, namely the resistance to stretch that increases the stored energy in the bow. 

THAT being said, I have no experience in using Gorilla Glue with sinew.  I could be wrong. 

And a side note:  If you have Gorilla Glue in your house, keep it far and away from dogs.  Apparently it smells amazing to them.  They are driven to chew up the bottles and swallow the glue.  Once in their stomachs it expands and sets up, blocking the digestive tract, if not bursting their stomachs.  A number of people have found this out firsthand with tragic results. 

[Bryce]

Polyurathane glue is garbage bro. It foams and bubbles leaves air pockets and is weak accord to industrial standards.

For sinew, I was making my hide glue for the longest time. Decided to give Knox Gelatin a try.(which is refined hide glue for consumption) and I cannot tell the difference. Some ppl will argue that its not as good but......there wrong.
I've also recently tried the titebond liquid hide glue. Which works really good as well.
Sinew backing in my opinion cannot be done properly w/o hide glue. It's like peanut butter w/o jelly.
JW said it best.
 

  The idea of using hide glue is that the two materials molecularly bond with each other creating a magnificently homogenous material. 

Well said.

[Sempertiger]

I'm fairly sure the OP isn't talking about the original Gorilla Glue, the foamy stuff. They do make a woodglue that looks and behaves similarly to the TB products.

Honestly, when I get into doing sinew, I plan on making hide glue and using that. If wood glue was a superior product for this application, everyone would be using it. Also, If i'm remembering correctly, the TBB series has a glue comparison section, and I think normal wood glue is around 30% weeker than hide glue, and fish bladder glue is 10% weeker than 2 ton epoxy, and 30% stronger than hide glue.

[beetlebailey1977]

From the Bowyers Bible volume 1

They actually talk about how you can put a thin layer of hide glue onto glass and when it dries it will pull up glass chips.....hide glue has 10,000 plus pounds of tensile strength.  They also say that the knox gelatin was about 4 lbs. stronger in the glue test that regular hide glue. 

[Prarie Bowyer]

When I do sinew backed bows I use hide glue. I know some use TBIII but I've not heard of anyone using Gorilla Glue. Give it a try on a test piece of wood.

Are there TB3 sinewing instructions someplace?

[Prarie Bowyer]

From the Bowyers Bible volume 1

They actually talk about how you can put a thin layer of hide glue onto glass and when it dries it will pull up glass chips.....hide glue has 10,000 plus pounds of tensile strength.  They also say that the knox gelatin was about 4 lbs. stronger in the glue test that regular hide glue.

WAIT WAIT WAIT. ... So Hide glue is the strongest glue assuming we mean water based glues?  And Knox Gelatin is stronger than that?. 

I gotta say I LOVE TB3.  I keep some around for all sorts of stuff.  I only use Gorilla's thick super glue.  The foam glue is not taht great in many applications.  I worked at a sign shop that loved the stuff for gluing up sign blanks.  However we switched to TB3 becasue of the quality aand cost differential pluss ease of clean up.  Butt he number one feature was the Water Proof nature of the stuff.  how would you water proof hide and Gelatin glue?

Where would Urac fall on that list?  I LOVE Urac now. I notice that it dosent bond to my baby food applesauce cups I mix it in ... allowing me to reuse them.

[JW_Halverson]

I tried making up a batch of water-resistant hide glue.  No hide glue will ever be waterproof. 

In the first Bowyers Bible there was a short line on how tannic acid helped hide glue resist re-hydration.  So, I filled a 5 gallon pot with oak bark shredded fine, topped it off with water, set it to soaking for a few days.  Once the bark was well hydrated the water looked like coffee.  I then set this on to boil and boiled it all down for 6 hours.  I strained this thru cheesecloth and ended up with 3 qts of concentrated oak bark dye.  This is also the liquor you would use to tan hides, since the main compound is the tannic acids from the bark.

I then filled a roaster with 3 lbs of scraps of elk leg sinew, deer and antelope back/leg sinew scraps, and any bits of rawhide left over from projects.  With the black brew poured over the scraps I tossed it all in the oven at 165 degrees F for 8 hours.  I added distilled water to keep the sinew covered.  The whole batch was again strained thru cheesecloth and set in the fridge to gel. 

How did this batch of black hide glue work?  I dunno.  Haven't had to sinew a bow for a while, so it just sits in the freezer.   

[Prarie Bowyer]

I guess you could do a top coat of TB3 ....
I'll have to keep that in mind. 

How do you work with the gelatin as glue?

[bubby]

waterproof it buy skining your bow with rawhide or snakeskins with tb3, Bub

[Jude]

Consider how stretchy and resilient that piece of glue you found is, and compare to how stretchy and resilient a piece of dry rawhide or sinew is not.  That is what hide glue is made of and that's part of the reason it's stronger.  On top of that, it forms a molecular bond with rawhide, sinew and wood, and it shrinks as it dries, drawing the joined pieces into tighter contact.  Dry sinew is in fact stretchy, but more like a steel cable than a rubber band.  It requires a lot of force to stretch it a little bit, and consequently stores a lot of energy.  You don't want a stretchy glue zone when you are trying to transfer force from one layer of a laminate to another, regardless of the materials.  If the glue joint creeps, the back won't be doing the work it should.

[osage outlaw]

How do you work with the gelatin as glue?

I mix a few packs of gelatin in cold water.  I mix it until it is kind of thick.  Then I microwave it for just a few seconds to get it warm, but not to hot.  I have a hot plate that I put a pan of water on and then put my bowl of glue in the pan of water, kind of like a double boiler.  If the glue gets to hot, it will make the sinew curl up and ruin it.