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Yew billets belly drop build with sinew backing.
superdav95:
Still working on these bows…. I got the sapwood one sized with watery thin sinew glue I made from my scraps from processing the moose sinew for these bows plus a few extra scraps from previous. It took about 20 coats! Letting each dry to the touch each time till I got to the point of a noticeable shine when dried. This yew sapwood soaked it up like a sponge! Should hold very well indeed. The glue was very thin so good penetration into the wood pours and surface fibers. I also used a Grobet gimping file from my knife making days to put my surface grooves in. Ive used this technique a few times now and it’s a very good consistent way to get clean fine grooves on your glue surface. I do this with sinew and horn belly lams too. For the horn lams I use the courser grobet file. I use the finer one for sinew. Not sure where I bought these but they work awesome. I have used hack saw blades and other blades mounted in a scraper with success too. The key is to get them smooth and clean. Most important thing in my opinion is adequate sizing of very thin glue. Can’t stress that enough. The failures I’ve had on earlier build in past I attribute to lack of proper sizing. I grooved both bows with same fine file. I wire brushed after each and wiped down with damp cloth with acetone. I let them dry and started sizing. Like I said the one with sapwood took 20 coats of thin sinew glue and the heartwood only bow took three coats of 50/50 mix water and tb3. I used a burner in the stove to warm up the surface of each bow before sizing. The tb3 seeped into the grooves and fibers of the heartwood well and followed up with two more subsequent coats which hardened up nice yet still leaving the fine grooving visible. I will use this same 50/50 mix to soak my damp sinew bundles prior to applying on the bow. I will follow up with full strength glue and then wrap it tight with a cloth wrap. I will likley hot box this tb3 and sinew bow overnight. I’ve not done this before with other instances of using tb3 and it may not be necessary but I’m thinking at this point that I may. As for the sapwood one I’m going for one layer with a handle overlap into the fades. Sinew for Both limbs will be weighed and measured for length to balance out the sinew applied to each. I will likley do 30 grams on each limb and a handle section of 5-10 grams.
The two bundles seen in the pics are what I’ve got for the 2 bows. The big bundle is 104grams of good long moose back strap. The other is 19grams of washed moose back strap med- long strands. This is the bit that I started with on my chew experiment that ended in disaster. I rewashed it all and dried it out again and will reuse it. I hope to get them both backed today. Thanks for following along. Dave
superdav95:
Here’s a pic of those file for those interested and the sinew I’m using and glue I made with the scraps. For the glue I just use a crock pot on warm setting for 2 days. I then blend it all up with a Braun mixer and let it go another 6 hours. Temps were kept below 80-90 degrees. I then cut up the gelatin into small chunks to dry for a few days with a fan blowing over them. This has made me great glue in the past.
GlisGlis:
--- Quote from: superdav95 on January 31, 2024, 01:54:35 pm ---For the glue I just use a crock pot on warm setting for 2 days. I then blend it all up with a Braun mixer and let it go another 6 hours. Temps were kept below 80-90 degrees. I then cut up the gelatin into small chunks to dry for a few days with a fan blowing over them. This has made me great glue in the past.
--- End quote ---
what water/sinew ratio do you use to make glue? do you have to add water during the 2 days of slow cooking?
superdav95:
--- Quote from: GlisGlis on February 01, 2024, 01:20:36 pm ---
--- Quote from: superdav95 on January 31, 2024, 01:54:35 pm ---For the glue I just use a crock pot on warm setting for 2 days. I then blend it all up with a Braun mixer and let it go another 6 hours. Temps were kept below 80-90 degrees. I then cut up the gelatin into small chunks to dry for a few days with a fan blowing over them. This has made me great glue in the past.
--- End quote ---
what water/sinew ratio do you use to make glue? do you have to add water during the 2 days of slow cooking?
--- End quote ---
I kept this batch quite thin so that I could use it for my sizing coats. But normally I make it little thicker. As far as ratio it really doesn’t matter in the end so long as you get a fairly firm gelitan mass that you can cut up into small chunks and let dry to 100% glue. It will be rock hard. I like to keep it fairly this so that it strains well too to get good clear glue free of most of the little bits and floaties. So no measurements on water to sinew. I just had basic estimates of 200-300 grams of sinew scraps and filled my crock pot up with water. I added another 500 mls by day two. Hope that helps. Here’s a pic of what I ended up with after 3 days of a fan blowing on my little chunks on drying racks.
superdav95:
So I got my bows sinewed yesterday and wrapped. Here’s what I got after removing the wraps this am. See last 2 pics. As far as my set up and bundles pic one shows that laid out. Again as I mentioned earlier I sized both bows very well before getting here. I think this is key to success with sinew. I got a criss cross pattern on the sapwood one a bit more then I wanted but not a huge deal. I’ll smooth that out a bit more when it surface dries a little more. So. Here is where I’m seeing a difference already. I had suspected that the tb3 variant would have more mass retained. This seems to be the case so far. Time will tell. Both bows were weighed before sizing coats and laying down sinew. The weights recorded the following day includes the the addition of the back set string. The sapwood bow weighed 645.55gr before sizing and sinew. The day following sinew it weighed 797.07gr. That’s a difference of about 151gr give or take. The heartwood tb3 bow weighed little more to start at 675.25gr then 833.63 respectively after sinew. That is about 158.gr give or take. So we shall see how things go as the days go by. Gonna see how these measurements drop each day and record them down. I suspect it will take several weeks if not months to get to the point of bending these again. Anyway here are some pics.
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