Some sinew Qs

[tetaxidermy]

Got this 56'' osage scrap, only 1'' wide. Basicly a gullwing shape with flipped tips and pin nocks. I put one course of sinew on yesterday, borrowed Pat B's idea for holding the bow. My questions are, how long between courses, and how many courses? I was thinking 4 layers. Also how much weight will it add, left the bow at 50# @ 27'', after retillering when sinew dries would like to keep it in that range. Thanks, Eric.

[Keenan]

 If you are trying to up the poundage go with more. However two good layers of sinew should be ample to protect and see some benefit as well. With two layers you'll probably gain about 5-8 lbs. With 3-4 layers of sinew, it can start pulling and moving limbs and tips more, and may require more tweeking. Keep in mind that sinew can be affected by weather and therefor the bow might be prone to changes when in foul weather conditions if you have more then a couple layers.

[Pat B]

I've only done a few sinew backed bows so take this for what it is worth... I would add a layer of sinew, give it a month to dry and add the next. With the second layer I try to fill in the areas that have less sinew to even out the sinew backing. I let that layer dry a month and do a third layer to make a smooth(er) back surface.
  With the 53" sinew backed osage I'm working on now(the one I used the sinew loop and cup hook to hold reflex) I put down one thick layer of leg sinew(2 layers I removed from Elkie the last time) then about 3 or 4 stripped out backstrap sinews for the top layer with a month between layers. Last week I added the snakeskin with hide glue so I'm waiting more than a week before moving forward. I did brace this bow, evened up the tiller and shot it a dozen or so times before adding the snakeskin.
  The sinew will continue to cure out for a while so why rush the process. I'm sure some have and been successful rushing through but for me the process is what it is all about.
  I think a lot depends on the bow as to how much weight you can add by adding sinew. If I start with a freshly tillered bow of 50# and add the sinew before shooting the bow in I will end up with a 50# sinew backed bow or maybe a little more when the bow has been final tillered, finished and shot in.     

[tetaxidermy]

Not realy trying to add weight, just wondering how much I was going to have to take back off. Waiting won't be a problem been working on this one for several months now off and on, trying to get it just right. Lots of other projects to do in between. Thanks for the good info. Eric.

[blackhawk]

Yup...two layers is enough...and that's a sweet profile...its looking good so far

[tetaxidermy]

Thanks blackhawk, been wanting to do this one for a while. It called to me this weekend, had a black locust failure, figured I would go back to some yeller wood for awhile and ponder how to aproach the locust. Sneak up on it mabey.

[Marc St Louis]

You can put all the sinew on at once.  I have put up to 5 courses in one shot, more than that can be problematic.  Just make sure you put the bow in a place that has a lot of air movement.

[gstoneberg]

I have not seen a lot of weight gain with 2 courses of sinew with my osage bows.  I always do both courses at one time, and I never go with more than one sinew layer on the bow tips to keep weight down.  The rest of the sinew I keep just on the working part of the limbs.

I'm curious why you're adding the sinew if you're at your target weight and draw length?  Are you going for a longer draw than 27"?  I avoid adding it to bows these days if they're working without it.  If you don't need more draw weight and are just protecting the back I might stop with a single course of sinew.  From your pictures it looks like a real nice sinew job.  I'm anxious to see your bow finished.

George

[tetaxidermy]

George, it is mostly for protection. The bow is only 1'' in width and 56'' long just making sure it stays together, and mabey add a little snapiness. Will post up pics when done.

[gstoneberg]

I'm working on a 1" wide 52" osage bow now and I plan to sinew back it because of a bad check on one tip.  We'll have to compare notes when we're done.  It is my 3rd 52" osage bow in the last year.  The other 2 are unbacked, one pulling 25" and the other 27".  I don't think you have much to worry about at 56" with a bendy handle.  As we're fond of saying, it doesn't take much osage to make a bow.  I'm pretty sure the first course would be more than enough to protect it, but it'll be even stronger if you put on 2 courses.  I've not broken a bow yet that's been backed with sinew, though I assume it'll happen as I continue to build more of them.

Good luck,
George

[tetaxidermy]

We'll have to do that, put second course on yesterday. Going to let it cure for a couple of months while I work on some other bows. Time will tell as they say. Eric.

[crooketarrow]

  I've did it where I've let it dry a week,2 weeks and 3 and 4 courses at once. Really doesn't matter you let if completely dry in the end. I've but mine in  Hot box for a week but if you do this remember you have to let it rehydrate. Don't dare pull it give it a week.  I let mine dry a month 2 with 4 or 5 course's. THE WARMER IT IS STORED THE QUICKER IT WILL DRY.
  If you just wish to protect it there's other ways that take farless time. The more layers the better it will hold form. Osage will increase case. Remember with small limbs each layer increases mass and in the long run will make it slower not snapper. Osage is super tuff and 2 or 3 layers is plenty. I'd get around 2 to 3 pounds a layer.