Dry vs "seasoned" sinew

[Eric Garza]

Eric I think you might have missed the point that Pearly was making.  When it comes to bows, short is a relative term...

I think I get what he's trying to say now. Thanks!

[loefflerchuck]

If the question is about a all wood bow with 2-3 layers of sinew, not very wide, not a huge amount of reflex, and with a draw of about 1/2 the length of the bow. Then there is no reason to let the sinew season for more than a month(not that it would hurt). The reason the turks let them season for a year+ is that these bows were under a huge amount of strain with a large layers of sinew. When you are starting to bend a bow with the tips touching with reflex and ending with a bow that has a extreme overdraw then we need to look at using only the best glues with the perfect setup time and allowing the collagen to form complex bonds over months. I feel I have done my fair share of experimenting with sinew. I've made juniper and cedar(incense cedar not erc) bows with 5-7 layers of sinew. Sometimes shooting in only two weeks. Yes the tiller changed in time but the reflex just continued to grow. I didn't become obsessed with good glue and seasoning time till I started making horn/sinew only bows that are 50% horn and 50% sinew on average. The sinew would draw the bow into a reflex as high as the bow was long. A O shape missing the top. I would start to bend and tiller the bows after 2 months of dry time. Plenty of time for the complex glue bonds to form. The problem was I would still be tillering this same bow with heat and sand paper 3 months later. If I wait 6-8 months, when it's tillered it's done. This is a different game. If you are asking about a 52" wood bow with 2 layers of sinew that you will be drawing 26", then by all means go ahead and shoot it after 3 weeks

[PEARL DRUMS]

Thanks for all the feedback Chuck. This was a good thread.

[PatM]

One thing I notice is that no matter how long people let their sinew cure it still gets that "hammered"  look after the bow starts bending. This must be from the glue microfracturing due to the glue bonds failing.
 I wonder exactly how complex these bonds are actually becoming if after months the glue is still failing to a degree and only the sinew is actually in any degree of continuity.
 I have been experimenting with a few ideas to try to get the glue to hold up better under this stress where it still appears clear after bending. Just time doesn't seem to be the answer.

[PEARL DRUMS]

Pat Ive made 8-10 sinewed bows and none have ever taken on that hammered or cracked look you speak of. Ive never even heard a crack or pop once I start bending the bow? I contribute that to the glue quality and quanity. I leave very little glue behind.

[PatM]

I think that is a large part of achieving that. Good glue and less of it.
  Where do you normally let your bows cure/dry and at what temperature?

[PEARL DRUMS]

62-64 degree's, 25-35% humidity. I usually have a 3-4 month window to sinew bows. If I miss it, I wait a year. I tried sinewing a bow in 60-70% humidity and it mildewed fast. I have a quanity of glue and back straps Ive used for all of these bows. Its nice knowing the materials are the same and the results have been as well.

[Pat B]

I've never had the scary popping sound on any of my sinew backed bows but I squeegee most of the glue off of the sinew before I lay it down. I do sometimes add a thin layer of glue over the sinew after it is all down but that is mainly to smooth out the surface.
 I usually store a freshly sinewed bow in our utility room over the hot water heater to cure. The utility room is slightly cooler than the rest of the house and there is good air circulation near the gas hot water heater. Inside of our house is quite dry during the winter. This past summer when I built my last sinewed bow was the wettest summer we've had in a long time with over 40" of rain in June, July and August. That is one reason I allowed about 3 months before stressing the bow.

[Eric Garza]

I've only had one sinew-backed bow, out of perhaps a dozen, develop that 'hammered' look and thinking back it was because I used way too much glue. Now I squeegee as much glue out of the sinew before I lay it down as I can, and remove more glue by heating the backing and pressing it with cloth. I also use sinew glue that I make myself the same day I'm laying down a backing, and monitor the glue's temperature so as to minimize denaturing the collagen in the glue.

[mikekeswick]

By definition they are the same thing?

The tiller definition? No. Marc refers to tiller changing and PatB refers to "tillering" the bow to a reduced weight due to the bow gaining weight.

The same thing as in the woods properties have changed. If the tiller changes - something has changed. If the bow gains weight - something has changed. What you call the process of getting it back to where you want is immaterial.

[PatM]

Your question was kind of vague and I wasn't sure what you were getting at.
 I wouldn't call weight gain a change in tiller or a change in the property of the wood.
 I was merely trying to narrow down what Marc meant since he wasn't clear.

[Gus]

This is some Good Stuff y'all...

After reading through this Thread a couple times.
I realize the only part that I have any first hand knowledge of is in Processing Green Sinew.
And now I find myself wondering if the way the sinew is cleaned can have an effect.

I usually Clean and Dry my sinew in One Gallon Bag size batches.
Process as follows:

Thaw a Gallon Bag of Back Sinew.
Scrape each piece as clean as I can of Meat.
As each piece is finished I drop it into a pot of water with Dawn Dish Soap to soak.
When the batch is scraped and in the Soap and Water Soak I wash it vigorously changing soap and water several times.
Once the water runs clean, I fill the pot with fresh soap and water, cover and place in the Fridge.
I then wash and rinse at least once per day for three to five days.
When I'm happy with the Color and Smell of the Sinew, I hang it to dry.
I let it hang for three to five days or until fully dry.

During the wash - rinse cycles most if not all of the Slippery Membrane is removed.
And at each washing I wash and rinse till the water runs clear...

Just Food for Thought...

-gus

[Eric Garza]

Hi Gus, I use a generally similar method for cleaning back tendons, although I scrape the membrane off when I scrape the meat off the other side, and I dry sinew on parchment paper under a fan rather than letting it air dry while hanging. Not sure that either of these differences matters that much. Getting that membrane off makes the sinew much easier to separate into fibers though.

[Marc St Louis]

When I said changing tiller I didn't mean draw weight change, that is mostly due to moisture change in the bow.  No if a sinewed bow that has not been left to cure properly is tillered out and then left sitting for several months it will have issues with the bow going out of tiller.  Anyone else have this happen?

[Eric Garza]

I've had this happen on earlier bows where I ended up with too much glue in the sinew-glue matrix. I suppose it could be due to sinew curing, but I've always assumed it was because the glue was still drying and that I had used more glue on some parts of the bow than on others, yielding a changing density of the backing matrix. But I admit I never thought to study it too closely, so I could be misinterpreting what was going on. I haven't had this happen in the last several bows I've made, as I'm a lot more careful now about minimizing the amount of glue I use.