Sinew glue-a-long help

[osage outlaw]

I want to try to make some sinew glue for backing bows.  I could use some help with it.  I just finished sorting my scraps.  I pulled out any dark pieces and anything with fat on it.  I ended up with 4.5 ounces of clean scraps.  I am going to put it in my crock pot and cover them with water.  Should I cook it on high or low?  With the lid on or off?  I know I don't want it getting to hot.  And how long should I cook it?  I will post updates as I go along.

Clean scraps and dirty scraps

[Bevan R.]

I would think low. I understand you do not want it to boil.

[Keenan]

Clint your pile looks great. I cook mine on hi with the lid on. That is just below boiling on most crock pots. It will bubble hen you first pull the lid off but it will be fine. I fill it a little over half full and start it at bed time and it will be glue by morning. Just through what you don't use in the freezer until needed.

[osage outlaw]

Keenan, does it really take that long to cook?  I just turned mine on.  I guess I could turn it off and wait until tonight to start it.

[toomanyknots]

This il be fun to follow. My last sinew glue was all cracky and crappy. The bow I sinew backed with it is still shooting after almost a year now, and has about 1" of reflex right now I think, it went from like 60# or so @ 28" to maybe like 75# or a bit more, at least that is what it feels like after trying to draw it the other day.  :laugh:It only has one layer of sinew too. The glue cracks to hell at back when I draw it, so it is not that much fun to shoot. I have read in TBB once that boiling for a couple hours make glue only a small bit not as good as simering for 5 or 6 hours. Now that confused the crap outta me as I have read and heard, as have everyone else I think, that you should never boil hide/sinew glue, as it il weaken the glue. I do my best nowadays to simmer for a good couple hours. I have never made glue in a crock pot, but I'm about to try it out also. My old lady recently decided that our crock pot is broken, as it "doesn't even get that hot", according to her. LOL LOL So she said I could use it... I not entirely sure that she really knows how a crock pot works, but I am not gonna argue!

[adb]

If you don't want to end up in the dog house, especially today, you'd best cook it outside, or in the garage, cuz it really stinks.

[osage outlaw]

Thanks for the tip.  Its in my work shop in the garage.  My wife complains about the smell when I cook deer meat.  I could only imagine what she would say to cooking hide glue in the house.

[toomanyknots]

Clint your pile looks great. I cook mine on hi with the lid on. That is just below boiling on most crock pots. It will bubble hen you first pull the lid off but it will be fine. I fill it a little over half full and start it at bed time and it will be glue by morning. Just through what you don't use in the freezer until needed.

You usually have big chunks in the glue left over in  the morning, right? Do you usually throw them away, I used to grind them up to liquid in a blender and then use it as glue, but I think that may not be the best thing? I have tons of glue questions. It seems to me that my glue doesn't get sticky until it is pretty thick, which is when I use it when it will stick my fingers together. But then it starts to get little glue balls everywhere and all over my hands. Or that my be it is drying to fast. The last bow I made has cracks covering the entire back, I could almost tiller the bow by telling where it is bending more by the cracks it is so bad. I'm hoping as some guys on here have said that it is because of the glue being too thick, is your guys glue sticky when you use it? 

[osage outlaw]

Did you strain your glue when you were done cooking it?  Maybe it was to thick.  I don't know.  I have only used knox gelatin and I didn't get any cracks in my sinew back.  The knox it thin stuff but very sticky.

[JW_Halverson]

Lower, slower, and longer is the best hide glue.  That's why I use the oven.  I can keep my oven at about 170 degrees F/77 Celsius.  It never approaches boiling that way. 

As long as I keep a cover on the pan (I use an enameled roasting pan) I don't lose so much moisture.  If it does lose moisture, top it up with distilled water.  In fact, use distilled water for the batch, I can only imagine the dissolved minerals and salts can't help the glue any. 

[osage outlaw]

Now you tell me JW.  I forgot about distilled water.  I used tap water.  Oh well. 

I rigged up a hillbilly coffee can strainer.  Maybe I should make another one.  It might clog up fast.  Will this aluminum pan work to dry the glue in?

[criveraville]

Good thread here amgio

Cipriano

[osage outlaw]

I turned it down to low for the night.  I will check it first thing in the morning and see what I have.

[Keenan]

I use paint strain filter for mine. As far as sticky it seems watery until you start soaking the sinew bundles. They will just add to the stickiness.
  Guys everyone seems so worried about a crock pot getting to hot on Hi and it simply isn't anything to worry about.  I have a dedicated crockpot and have done more batches of sinew glue then I can remember.  I have only had one time when it lifted slightly and that was due to lack of surface prep.
 Several things I like about "true sinew glue" is that it seems to soak in slightly deeper because of the watery tendency and gets the glue beneath the surface of the wood. Yes that adds more moisture to the wood and can sometimes take longer on the curing then tightbond or other glues. However I have tested it several times and it will often rip the wood before pulling off the bow back. It should be noted that I have not sinewed Osage and most of my experience is with white woods
 

[MWirwicki]

Good thread here.  I won't address the making of the glue because you all have that covered.  As for the cracking of the glue once it is on your bow, I'll address that. 

In my experience, it has nothing to do with the quality of the glue or how you processed it.  It is a meter of how much glue you are using when applying the sinew bundles to the back of the bow.  First, the glue doesn't have to be Aunt Jemima syrup, thick.  When it is, it will set up faster causing your "glue balls".   Second, apply a very thin coat of hide glue to the bow back and allow to soak in slightly prior to applying any bundles to bow.  This is called, sizing.  Then, dip your bundle of sinew into the hide glue and squeegee off the bundle between your fingers removing excess glue.  Apply the bundles to the back of the bow as though you were shingling a roof, alternating bundles so as not to have a continuous seam across the bow limb.  The key to reducing the cracking is reducing the amount of glue.  There is a tendency to use too much glue and it is not necessary.  I've also seen some bowyers fill voids between sinew bundles with hide glue to get an even appearance.  This will also cause the cracks in your finished product.  Keeping a moist towel (not your wife's monogrammed his/her towel) near you to wipe your fingers between each bundle, helps with the "tar and feather" syndrome.

Sinewing is something that takes a bit of practice.  You'll get better at it as you discover your own little tricks.