Hold my hand when I sinew my first bow

[jameswoodmot]

So my laminates have started over as I found out the hard way my cascamite had gone off and my yew is still drying. My 100lb roving bow still isn’t down to low enough moisture so I started another bow!

I’ve been waiting for the right elm stave to practice sinew backing. This one is 43” from the top of a sapling I took down. 1 5/8” in the middle down to 1” at the tips

Gave it a cook over coals, it’s ready for a short string.

It’s got a little bit of snakeiness and a little knot in the middle and quite high crown. Are these likely to cause an issue?

My tendons are roe deer leg tendons so pretty short but it’s all I can get.

Any suggestions as to weight of sinew and how many layers? I know it’s an open ended question but it would be good to have a guide for the first one

[jameswoodmot]

Little knot and the reflex

[superdav95]

It’s a great candidate!   What are your longest strands?  I would lay down a brick pattern with shorter sinew strands.  This allows for staggered and methodical approach to laying it down.  I measure in dried pounded and stranded sinew bundles.  I then lay down either a single combed bundle premeasured by dry weight for each limb.  I save the shorter strands for over the handle area to overlap a bit.  The brick wall pattern would be good for shorter strands.   Ask away any questions. Lots of experience guys on here. 

[bjrogg]

I’m going to be watching this one to. I still haven’t done a sinew backed bow. I know Dave knows a lot about not only applying it, but also preparing bow for it, making glue for it. And knowing how to use it all.

Bjrogg

[jameswoodmot]

Thanks guys!

Averaging about 6-7” long, tearing it up now.

I’ve found if I shred it too much it starts to turn into a curly mess so I’ve left it slightly coarser.

Going to use commercial hide glue bought as dried granules.

I was thinking about tbb with the diagram of the brick pattern. Are two layers ok for this or would three thinner layers be better? I’m thinking also that because of the crown that perhaps applying slightly more to the centre of the crown and less to the outsides.

[superdav95]

If it were me I would really clean the sinew very well. Your hide glue will work just fine.  Separating bundles of strands into short medium and long can work well if using a brick patters.  I would measure the amount of sinew you want for each limb.  The last couple I did that were a little longer then your bow here each took about 70 grams dry.  So basically equal mass in glue general rule of thumb.  Depending on your glue and how it’s done can be a little less glue but risky.  I always mix up a little more then I need at approximately 25-30% strength.  If using granule glue just start with small mason jar with 75 grams of water and then add your granules till you reach 100 grams.  This will give you 25% glue.  If preparing the back for sinew I use a fine toothed hacksaw.  And run parallel grooves up and down both limbs.  I then take a stainless wire brush to clean out any debris.  I size coat with 5-10% glue about 10 times. This allows the pours of surface to really open up to accept the glue and adhere well for sinew.  Basically coat with a brush letting it dry to the touch warming slight the wood.  It will be shiny.  It may be overkill for sinew but you won’t regret taking the time to get it sized well prior to sinew.  Measure each pile for each limb to be as prices as you can to not end up with way more sinew on one limb then the other.  I comb my sinew and clean it well with my fingernail its entire length dry first to pull into finer strands.  I then comb it with a dog brush to even finer strands.  Doing this will give a very clean surface.  These bundles when layed down can be smoothed out with fingers dabbed in some water.  I use a heat lamp to keep things warm aimed at my work.  Another trick I’ve done with brick pattern sinew to get a smooth finish is to let the sinew gel up well and start to just be dry to the touch on surface only and then wrap it is with a t shirt stripped out or some sort of bandage.  I don’t use tensor bandage as it has a little too much elastic but instead I use horse leg wrap.  This stuff is very thin and leave virtually no wrap marks and compresses just enough the sinew to make it smooth even with brick pattern or laying it down.  Works well.  I’ve posted on this method using wraps.  If you search my yew bow builds last year or so I show it.  I know it’s there I just sent link to someone else recently with similar questions.  Anyway.  Don’t be afraid to get messy.  The sinew will stick to you and be like playing with wet spaghetti noodles.  Is you sinew fairly clean when pounded up?  Leg tendon is good for giving clean sinew dry.  There will be some pieces that will have extra bit that would need to be washed and combed for best results. 

[jameswoodmot]

Fantastic thanks Dave you’ve already answered many of my questions.

When you say is it clean are you referring to the oily/residue or how cleanly the stands come apart? It definitely has some oiliness to it it I don’t have a lot to compare it to as I have only used one piece of roe back strap before. I have pulled out the short strands where the tendon splits into branches and done my best to pull out any short bits.

I will strip it down further into smaller pieces and  I doing so sort them into length (currently between 5” and 8”)

What do you recommend washing with?

[superdav95]

I use a dawn dish soap.  I wash it well in Luke warm water.  I’ve also soaked my bundles overnight for some of my moose backstrap as it has bigger strands.  I use a small stainless steel brush for final brushing to root out the clumpy bits that are sinew and remnants of casing.  The soap will help cut the oils too. Back string your bow too when you lay it down.  You can do one good layer or 2 smaller layers.  I’d let it dry a week or so between.   This may also give you the chance to fill in any voids or sand down any clumpy spots.  Keeping all the fibers is key to not have the fibers twist when drying under top layers of fibers.  I like to comb it the flip it and comb it again to be certain all the fibers are parallel

[jameswoodmot]

Thanks again!

Man, my hands know I was shredding sinew last night!

I’ve got 46g (1.6oz) of long 5-8” and 11g (0.4oz) of 3-5”. 2-2.5oz seems average for a 60” bow so I should have plenty there. As it’s Elm I would rather not over power the belly.

Later I’ll go through it all and sort the long bundles into two sizes and pull the longest pieces out of the short pile. Break down any larger looking bits and give it a brush through to pull out any stragglers.

I’ll get this bow to brace height and a bit further, score up the back with hacksaw blade, clean.


Does the sizing need doing at the same time as the sinewing or can I size one day and then re wet it and warm it back up again?

[Robert Pougnier]

Yeah is sinew is about as tough on the hands as it gets!

That's about the amount I added to my 60" hickory bow and It pulled an inch of reflex on it's own initially as it cured.

I've had no problem doing either. I prefer to let the sizing dry but you can size it just before you apply the sinew too. If the back seems to absorb a lot of the glue you could give it a couple of coats to make sure there's a nice solid base for your first layer to key into.

That's looking great so far and I can't wait to see how it turns out. Nice job!

[superdav95]

Thanks again!

Man, my hands know I was shredding sinew last night!

I’ve got 46g (1.6oz) of long 5-8” and 11g (0.4oz) of 3-5”. 2-2.5oz seems average for a 60” bow so I should have plenty there. As it’s Elm I would rather not over power the belly.

Later I’ll go through it all and sort the long bundles into two sizes and pull the longest pieces out of the short pile. Break down any larger looking bits and give it a brush through to pull out any stragglers.

I’ll get this bow to brace height and a bit further, score up the back with hacksaw blade, clean.


Does the sizing need doing at the same time as the sinewing or can I size one day and then re wet it and warm it back up again?

Ya it’s hard on the hands.  The way I do sizing for sinew prep is heating the bow slightly to open up the pours to better accept the thin glue.  I let it dry to the touch each time and with a little warm heat. Radiant heat.  I use a hot plate burner.  Do not over heat.  If you do see it bubble up let it dry and scrape it off and restart.  I go as many times with warming it and adding another size coat till it looks shiny but still thin.  This can happen on same day as laying sinew.  I would scrape the back and size coat the same day.  Sinew can wait to be done as long as you want after sizing.  Just wet it slightly with warm water just before starting to lay your bundles.  It’s also good to have a system written down.  You’ve spent all that time and energy get to this point so keep good notes.  I like to draw out a diagram even of how i plan to lay out my staggered bundles with check boxes. This way if something happens and I have e to leave and come back I can pick up where I left off.  Notes are good to keep for future builds too. I’ve often referred to my old notes as my memory is t what it used to be and I also can spot irregularities later to be improved upon. Sounds like you made some progress.  Don’t worry about measuring out too much glue.  You can always freeze it to be used later.   When you are about to lay sinew it will all be laid out in measured bundles that are damp, clean, combed straight and brushed of debris.  I dip my bundles right down into the glue and squeeze out the excess glue and lay it down. Best of luck and keep us updated.   

[jameswoodmot]

The first couple of coats of size is going on.

Got it braced today and the back scored with hacksaw blade. Had a bit of an issue with it getting fluffy as I wasn’t diligent enough keeping the lines straight but I got it cleaned up. Degreased with isopropyl alcohol.
It looks like it’s getting pretty well soaked in already.

I’m sorting my bundles for sinewing tomorrow.

I’ve got about 1.6 oz. I was counting strands to groups of 6 which quickly became obvious it wasn’t enough so I doubled it to 12 and for the one limb Ive got over 50 bundles. Does this seem reasonable, should be the bundles be bigger or smallr? I imagine smaller bundles will give a better backing at the expense of more time?

[superdav95]

Those strands will work but the finer you can get the strands to in dry form it will save loads of works and make combing them later when wet.  The ends tend to be clumpy and can hang up your comb even when wet.  The finer you get the sinew the better imo.  It will give cleaner more uniform layer too.   What ends up happening often is crossed fibers in the under layers of your bundles the create voids when it drys.  The key is to get it combed well which means combing through the hard clumpy bits at the ends.  In dry form I use my fingernail to scrape some of the end bit as good as I can prior to washing.  Your grooving looks fine and does not need to be perfect and straight even.  So long as it’s cleaned and free of any scrapings debris in the grooves to create possible air voids.   Size coat till the surface is saturated with glue.  Heat slightly to open the pours a little will help.  Not too much so as to have oils raise to
The surface like in the case with oily woods like Osage.  1.6 ounces is on the lighter side but could still work fine if you place it on critical spots.  I would lay around 50-60 grams so closer to 2 ounces.   I know it’s a short bow and if only looking for a little increase in weight or more for protection for a longer draw perhaps you’ll be fine.  I certainly would feel like any more than 60 grams would be needed.  The more smaller bundles could be more work for sure and may not be necessary.  You would smooth out with you fingers or the back of your comb anyway to make smooth.  Make your life little easier. It will still work.   Just stagger the bundles and blend them together as you lay them.  If it seems lumpy still wet your hands and flatten it down more as needed.  You will hear little air pops as you do this.  There is benefits to laying you first strip down the middle of each limb as you add to the sides to blend.  You will get a feel for it.  Just have a tub of water for your hands near by when laying.   I’m actually doing a little Osage 48” recurve right now!   I’ll see if I can take some video to post later. 

[jameswoodmot]

Ok I’ve just shredded a couple more tendons which has given me 12 ish more grams. I don’t want to use any more as that’s half of my sinew and I have the other half of this stave still.

I’m going to leave the strands as they are, honestly I’m bored of messing with them now. It’s just taken a fraction of the time to do those two extra tendons and now I know how it’s works when I do the next ones I’ll be able to shred them finer in less time. Will be interesting to see the difference between fine and less fine sinew. If this one’s a real munter I’ll cover it with a snake skin or something.

I made a right balls up of weighing out the strands and I’ve lost all faith in my kitchen scales so I’m going to get and get my micro scales from the workshop and also a halogen heater. I think I should have warmed the back more when I put the first layers of size down as I think I could have soaked in more.

Thanks for your help Superdav, a video would be awesome if your hands aren’t too sticky!

[superdav95]

James.  I have to apologize.  I had it in my head that this bow was longer than 43” and wider.    I think you’ll be fine with what you got.  It’s all depending on how much more you want to add draw weight wise.  My 48” 1” wide Osage recurve bow will be getting about 50-60grams fyi.  I’m hoping to get it on in one layer but we shall see how it looks as I get doing it.  I’m not going all the way to the tips either due to the recurves so it may be closer to 50grams.   Just a guage for your bow you may be fine with 20grams per side with an overlap at the handle.  I’ll get a video together and post it here tonight hopefully.    Sinew strands can be tedious to deal with and sort.  It goes quicker like you say with more experience doing it.   I will detail a bit on this in the video too.