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Questions on re-doing my bow trade bow…
superdav95:
--- Quote from: ssrhythm on February 14, 2023, 05:26:35 pm ---Yikes! I put it on the rack, and I damned sure know where the issue is now. It's a pretty large issue that I am going to have difficulty getting glue under. I'm shortening this bow by 4.5 inches, adding a bit more bend to the recurves and shortening or tightening the radius of the curves, heating in some outer 1/3 limb reflex, and then sinew backing it. It was 59 lbs at 28", so I expect that I am going to gain plenty of draw weight to eliminate this problem from the top.
I don't think the violation carried through and violated the next growth ring down, but I won't be sure until I get there...which tells you what direction I think I'm going to take with this one. I'm thinking my best option will be to remove 2.25" from each tip then get to work chasing the ring under the current back. Once that's done, I'll induce the reflex and rework the nocks and tips. Then I'll lay down the sinew and hope like heck that the bow is not just compromised with crappy wood at that point. There is not a knot or single physical issue that I can determine which would have caused the wood to crack where it did, so I may be about to waste a pile of sinew on otherwise great wood with one bad spot. I gotta give it a try though.
Worst case scenario...It goes boom despite a good sinew backing. Mid range result would be it coming in very light and turning into my kids new hunting stick. Best case scenario...I lose the poundage I will gain with the shortening, reflexing, and sinew backing and Mo get's a really sick little hunting bow. Let's see if I can pull this out of my a.....out of the fire.
--- End quote ---
Lots of potential still for you with this bow. I saw your video and felt your pain. I’ve been there unfortunately more then I’d like to admit. As for your plan of attack I think it’s good. If you can see the lift area is not deep and want to chase down to the next ring I would try that. If you don’t want to go that route I’ve also had good results with locking down the small area of lift or crack with very thin ca glue and varying on with sinew on the back. In fact that is essentially what I did with my bow I made last year called “bolt”. My fastest bow to date for me. The sinew will lock it down good and if it’s a minor tick issue you won’t even know it’s under there. Your plan for the amount of sinew is about what I did then and still do now. I’ve only ever gone over 90 grams once on a bow and it didn’t mean a whole lot of difference. More is not always better with sinew. You’ll add some mass with sinew as well so it’s a balance as you know. I like 80-90grams for my recurves and longbows. For my horn bows it’s less usually but can depend on the length and style. My last tartar style bow had over 90grams. It’s also around 75-80lbs. I think your on the right track though. It what I would do in your situation. As for heat treatment of the belly you’ll have to do this prior to sinew. I’ve never use urack glue and I know that others here have done heat treatment after backing with boo or solid type backing Sinew is not able to withstand the heat that will be applied to wood for heat treating to have an improvement effect on the belly. The cells of wood are already stressed and worked in this bow for the most part. This doesn’t mean you can’t see some benefits of applying heat. The tiller will change a bit with sinew but not significantly as far as the bend is concerned. This is more the case if you carefully measure out your sinew bundles dry in pre measured bundles for each limb. It makes a difference in the final tiller I found. I’ve had some bows that required next to no retillering after sinew on finished bows like yours. I like your idea I doin recurves to increase your string knock angles too. You’ll concentrate your bending area on where you place most of your sinew. I think your plan is good. I say go for it. Best of luck!
ssrhythm:
Thanks a heck of a lot for that info. Very helpful. I’m tempted to go with your thin ca idea, but the other alterations I’m planning on making to improve the efficiency are going to raise the draw weight by at least 20lbs, so I’m thinking if I’m going to take off enough wood to get it back down in the 50s, I might as well get rid of the problem area. I’ll keep you posted on how this thing goes for me. And yes, I agree about careful bundle weight and length prep. I looked over my notes from my hunting bow build, and I now remember weighing and matching and laying out each limb’s bundles to get them as close to equal in every way as humanly possible. Very little had to be done to get the tiller back to where I wanted it. Thanks again for your words of wisdom on this.
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