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Hold my hand when I sinew my first bow
superdav95:
I personally think you are fine now but that’s just me. It’s a good rule of thumb though like you say to measure weight loss and then a few more days. I keep my place here in Alberta around the 45-50% humidity. The air outside is far more dry though. I have a humidifier attached to the furnace which monitors this. So your level of humidity may change this a bit. I started bending mine about week two. I did mine right around when you did yours too. I measured weight like you are doing and then watch it stabilize and even go back up which is a good sign you are there. 6” reflex is good. It will mostly creep back to that after you tiller out the bow to what you want. I’ve even seen this reflex increase a bit as it gets tillered. This is because there is less resistance pulling back against the sinew and thus more reflex. I did some pre bending on mine before laying on my snake skins. I’ll start bending it again in a couple more days. I just glued on my handle today so will give it a couple. I posted a little about ratios on my little bow too but just to mention it here too I measure and premeasured my sinew and glue. I mixed up a tiny bit more then I need in glue but not a lot. I used most of it. My weight of the bow prior to sinew was about 65grams less then after the sinew dried. Some of this weight is glue. So in essence 50grams sinew and about 15grams or so in glue. After sinew dried my weight was 412grams. Prior to sinew it was just over 347grams. So about a 1/3 was glue give or take. I then added my snake skins which added about 8-9grams bringing it to about 420.86grams. It’s always good idea to monitor weight loss when it comes sinew. Lots of factors that can change things so results and dry times can vary.
jameswoodmot:
Thanks again!
My fear of moisture is actually more about the wood than the sinew. It’s 85-95% humidity here and 50 degrees outside. Don’t know what the humidity is inside. It’s so hard to get white woods down to reasonably moisture content in the winter here. The only thing I can do is weight for them to stop loosing weight and hope that’s enough. Got a moisture meter on the way.
I didn’t think to weigh the bow before sinewing, I had the weight written down on the bow as I was drying it before bracing but forgot to reweigh it after.
The belly had gone from flat, the concave, to now pulling slightly convex in places now which is interesting to watch. The back isn’t going to become flat but but to me that’s more of an indication of the shrinkage than the reflex.
I’ve got one thick patch mid limb where I had too many overlaps, I think it’s going to be ok but I may file it down slightly, though as there are overlaps I don’t want to weaken that point
superdav95:
--- Quote from: jameswoodmot on February 27, 2026, 05:41:50 am ---Thanks again!
My fear of moisture is actually more about the wood than the sinew. It’s 85-95% humidity here and 50 degrees outside. Don’t know what the humidity is inside. It’s so hard to get white woods down to reasonably moisture content in the winter here. The only thing I can do is weight for them to stop loosing weight and hope that’s enough. Got a moisture meter on the way.
I didn’t think to weigh the bow before sinewing, I had the weight written down on the bow as I was drying it before bracing but forgot to reweigh it after.
The belly had gone from flat, the concave, to now pulling slightly convex in places now which is interesting to watch. The back isn’t going to become flat but but to me that’s more of an indication of the shrinkage than the reflex.
I’ve got one thick patch mid limb where I had too many overlaps, I think it’s going to be ok but I may file it down slightly, though as there are overlaps I don’t want to weaken that point
--- End quote ---
Ya that’s high humidity wow. But don’t fret. That’s the best environment for laying sinew for best adhesion. It may take a little longer to dry but will be very solid. As far as the clump in the middle I would just smooth it out and not file down completely just yet till you get bending it. You may find out later that you can safely file it off. Keeping track of weights are important your first few bows to see patterns. Once you get a feel for it you get the ratios right and other things. The concaving of the belly would indicate drying and being pulled by the sinew.
jameswoodmot:
sinew is just incredible!
its a bow! I started bending it maybe saturday morning, just working it over my knee but wanted to give it another day to feel safe.
It was probably pulling about a million pounds so i needed to take a good bit of wood off, i had literally just got it to brace before as i had read it was best to not pull them before the sinew was on. I should have got it back to 15" or so inches, that way it would probably pulled more reflex when the sinew dried and i would be in a better place to start tillering.
Tillering went ok, i didnt know what my final draw length would be so i didnt know when to start getting the middle bending. I had no reference to know how much the elm would take with the sinew on it.
Once i got it bending it felt amazing, completely different to just wood or FG, just so elastic and springy. I was expecting it to feel like a heavier wooden bow but not at all!
Got it to 20" and shot it a bit and it was feeling fast. I wasnt really sure how the tiller should look, some similar bows on yt had all the bend in the middle and just straight from mid limb and others were perfectly circular with the same front profile. I ended up monitoring where it was loosing reflex, the tiller is a bit of a weird shape but the set/ reflex seems happy. then i took it to 22".
I guessed the reflex before with it strung backwards and the extra knocks added, its was actually about 4 1/2"-5" reflex to start with. It was coming back to almost flat in the middle 1/3rd right after shooting and maybe 2 1/2" reflex then and going back to 3 1/2" within 10mins. Think it was about 155fps 10.5gpp at 22" which i was dead happy with.
Then I shot it a bit more this moring and fiddled with the tiller some more, thinned the wood off the tips that wasnt needed and got it to 24". The reflex is still about the same i just managed to get some more wood working. i dulled it past 25" once for kicks and it didnt seem to mind at all. If i can get it to 26" thats my full draw but i'll not risk it as 24" is a comfortable short draw for me.
So then i backed it with birch bark, harder to do than the sinew!
pics incoming
jameswoodmot:
First brace and back to 22” then to 24”. You can see the weird looking tiller where it’s bending in the middle, then straight through the mid limb and them almost hinging just before the recurve. When unbraced it comes back to loads of reflex right where the hinge looking bit is and flattest where the straight sections are.
The 24” picture the left limb is great but it’s a bit stiff on the right inner and too bendy in the middle , this is exaggerated but the lighting/ shadow though it wasn’t quite as bad as it looks.
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