Questions and comments on the best sinew and hide glue.

[loefflerchuck]

I've made my own glue from sinew scraps and hide many times. I've always heard 12 hour glue made at home is far superior to commercial glue. From my experience a 315 gram strength glue I buy from a furniture supply works better than my slow cook glue. I would love some help with making better glue.
 My method. 1-soak sinew scraps in a few changes of dish soap and hot water to try and remove oils. 2 cook glue for 10-12 hours at about 160f for first poring. I've brought the glue to a rolling boil to skim off the bubbles of impurities that come to the top. Sometimes I have not. Just straining it through cloth and screen to dry. The glue is very clear and looks good but does not hold like the 315g glue I buy for high stressed horn bows.
 I am asking on hornbow page because I need the best glue. Even the worst glue I have made holds sinew to wood. Only the best splices horn and holds sinew to a huge reflexed horn bow. I would love some composite makers help on this.
 One more question. Would making your glue at high altitude yield a better and more pure glue? At say 8000 or even 10,000 feet water boils at a lower temp so the impurities could be skimmed off at a lower boiling temp.
Thanks
Chuck

[BowEd]

I make my sinew and hide glue the very same way but do not boil it towards the end.I have used a canvas sizing brand glue too on one backward C shape cured bow.The horn to core joinery held good to brace from extreme near handle reflex using the tepeliks.The usual time it should break apart.The sinew tore though.It was cured for over 2 years.I have not used my first pouring yet of sinew and hide glue to comment on.I'm personally going to try air bladder glue to mix in too.
Can't comment farther on the subject but there are others on here who can.I think they are mixing in home made air bladder glue too.
 

[loefflerchuck]

Thanks Beadman. The last 2 batches I made I did not boil towards the end. The sinew tore? I heard of that happening one other time but the sinew he used was very crushed in processing. I think it was pounded with a rock. Did your sinew actually tear or did it lift on a seam?

[BowEd]

Actually Chuck I sent my horn bow cured to England to Mike to tiller for me.I was stigmatized by making those tepeliks.He had been through it before making horn bows.I'm sure he'll comment on the glue question.He showed me a picture of what happened.It looked like it tore.Tips are'nt set back near enough.First attempt over 2 yeas ago.It's 52" TTT.Hickory/horn/sinew/mulberry sijahs.Next one tips are set back a lot better.Mike has that now too to sinew.Ironwood/horn/sinew/edge grain red elm horn inserted tips sijahs.48" TTT.



Sizing that horn I used very thin multiple sizings to get into every crevice.Sanding inbetween.

[BowEd]

This was bow before it was braced.

[BowEd]

[mikekeswick]

I think you are getting it too hot.
I make my glue at no higher temperature than 55 deg Celsius/131f. I also only heat sinew glue for 6 hours.
I don't use hide as it is so greasy.
Air bladders from the Yellow Croaker are superb for glue, they 'melt' at lower temperature and in less time. 3 - 4 hours is enough.

[loon]

I think you are getting it too hot.
I make my glue at no higher temperature than 55 deg Celsius/131f. I also only heat sinew glue for 6 hours.
I don't use hide as it is so greasy.
Air bladders from the Yellow Croaker are superb for glue, they 'melt' at lower temperature and in less time. 3 - 4 hours is enough.

Great to know... thank you... I've set my glue to almost 70C :\
I think my hornbow looks kind of like that... ...

[Stick Bender]

Pretty interesting topic you have going Chuck I wanted to ask you on the 315 g glue what your exsperience gel time was I used some 250 g for the first two layers on my curent bow & found it had to quick of gel time for me , that yellow croaker glue sounds interesting thanks for sharing that , Mike if you get a chance can you comment on gel time etc on it ?

[gorazd]

Beadman:

When looking on the crack of the sinew - I think that there should be more isue of the sinew (too thin layer) ....than glue ?

IMHO (not even first horn bow finished here  )  but At least conclusions from extensive experience in other composites (custom windsurfing boards - glass, carbon, kevlar, sandwich composites, vacuuming, etc ) ... glue is only a filler .... the fibers are doing the job - tension

[BowEd]

I think you are getting it too hot.
I make my glue at no higher temperature than 55 deg Celsius/131f. I also only heat sinew glue for 6 hours.
I don't use hide as it is so greasy.
Air bladders from the Yellow Croaker are superb for glue, they 'melt' at lower temperature and in less time. 3 - 4 hours is enough.

Mike....The amount of water used then cannot be much at those temps and time periods.I'm in the process of getting air bladders.Yellow croaker and catfish.Will use lower temps in the future.
gorazd....Yes the sinew may have been compromised before applying it too.Or tore so to speak.I know on that bow I put far too much sizing on over the finished job.Reason for cracking on the top layer too.

[BowEd]

There are plenty of videos showing the process of making sinew/hide/or air bladder glue but not of it being put to the test.I think as clear as possible/no odor product is a good indicator of strength.
I'd have to agree about hide glue being a bit more greasy.
Pre soaking the glue in a mild mixture of lye to plump it up to break down quicker I have not tried yet.Could easily be something to that.
These tests being done on the strength of the glue.Are they wood edge glueing then seeing if delamination occurs?

[gorazd]

Beadman :

I dont know how others are doing - I only looked at some videos on Youtube .... one Turks obviously dont remove shorter (and damaged) fibres from bigger bundle ,... but seems that Koreans remove shorter ones - and put them in thin uniform layers

So I washed the sinew strands (to get them very very soft and pliable) and peeled the wet strands to get very small diameter (less than 1mm) and removed every shorter strand - very time consuming - so ALL my strands were equall length... I noticed that quite a few strands are not so strong as other - I tested with puling with small force and removed breaked ones

Sinew which was naturaly dried  (from my butcher source - cow, young beef) does have less damaged fibers  than sinew I have got from pet-shop (Ostrich and cow sinew - tendons) which obviusly was in some hot air drying oven ... even when on first look they seemed OK (when breaking them apart in dryed state) -> some of them just poped when I wetted them !
 

[DC]

I don't have a lot of experience with this but when I was cooking up my dog chew hide glue I watched carefully for oil/grease floating on the top and there was none. I'm thinking that they maybe do some kind of treatment to get rid of the oils. Less stink for when the dog chews one on the living room couch

[BowEd]

Mike....I hope your right about this yellow croaker.Reducing easier then sinew.
My sinew before heating it were scraps of course[waste] and reduced very thin.
I will cut up these yellow croaker bladders very small to find out.Then use less water and heat for a shorter period of time.
DC...I think the dog chew things are soaked in some sort of chemical to make them more pleasant.What usually comes up floating when ever I do sinew is just a little foam in the center of the pot.Not much and nothing very foul at all.It gets skimmed off.
gorazd....Dried sinew tendons can naturally dry very hard just from air exposure.I've always pounded my sinew with a hammer and on a metal door weight too.Reducing stable strong strands to less then 1/16".Same length piles divided up into 4 or 5 piles.It could easily be the back of the bow should of had more of a crown.The core was slightly crowned and a flat grain belly piece of wood.