Questions on re-doing my bow trade bow…

[ssrhythm]

So my bow trade bow (you can look at it in that thread) was a little longer than it shoulda been, so I’m thinking that the bit of hand shock I wasn’t thrilled with was due to the length…67-68 inches ish.  It developed a “tick” after it was finished and when I was tuning arrows and getting speed numbers. 

I just got around to removing the snakeskin backing and I can not see a splinter anywhere.  I’m thinking the ticking was coming from issues in and around a cluster of three tight pin knots, but I can not see an obvious raised area.  I know it’s there…there is no doubt.

Question 1.  Do I string it and slowly pull it to expose the issue so it can be glued down, or do I just go forward with the sinew job thinking this will move the defect toward the neutral plane and the sinew will lock it down and support the compromised area well enough.

I’m fairly certain of the compromised spot, and I will be chopping 3” off each tip and instilling tight radius recurves to minimize string angle at full draw and maximize mech advantage while sparing as much working limb as possible.  When I cut and recurve, this cluster of pin knots will be an inch from where the curves start to bend and will be left stiff and non-bending.

I’m going to leave the tiny bit of set that took close to the fades, but I’m going to induce very slight reflex in the outter 2/3 of the working limb to give it a mild deflex/reflex design.  I want to heat treat the belly once limbs are reflexed…I know I’ll need to do this in the form.  I’m going to sinew the back.  I know the bow will be much heavier at this point, so ipoundage will have to be brought down during tillering.  So….

Question 2.  If I toast the belly and do a patient and thorough heat treat, when I start scraping and removing Belly material during tillering, will I simply be removing the heat treated wood cells and turning any heat treat into a “pissing into the wind” situation?

Question 3.  Has anyone ever successfully done a great heat treat after backing with sinew and after the sinew has cured?  I’m thinking to do good with a belly heat treat, the sinew backing job will suffer. 

Obviously, the heat treat of the belly is not necessary, but if I can pull it off, I’m kinda thinking “why not.”

Last question…for a 60-62” Osage recurve with 1 5/8” wide working limbs…
How much sinew would you use (grams or Ozs) to provide a performance boost as well as to provide protection?

Thanks in advance for replies.

[bjrogg]

Sorry I didn’t look at the trade thread, but I have few questions.

1# are you sure the tick is from bow? Or could it be the arrow? Have you tried drawing the bow without a arrow?

Have you tried rubbing back of bow with steel wool? If it has a lifted splinter the steel wool should catch on it revealing the hidden problem.

If steel wool doesn’t catch I would suggest stringing the bow and then trying the steel wool again.

I guess until I found the cause I don’t know if I could answer the sinew questions and I don’t have sinew experience anyway.

I would say heat treatment before sinew. I’m pretty sure heat treatment after sinew would be detrimental to your sinew.

Bjrogg

[ssrhythm]

Tic is from upper limb of the bow for certain.  If you go to the trade bow thread, I posted a vid explaining what happened and posted a vid of when the tic started happening, and you can actually hear it tic.  Then I shot it a couple of more times, and then I overdrew it and the ticking was worse and very obvious.  I need to do a little more scraping to get some more glue off, and then some sanding, and at that point, it may be more noticeable.  I was also thinking that maybe the bow was opening up some longitudinal cracks or other cracks that would not be detrimental to the integrity of the back.  IDK.  I figured I should probably string it and have my wife draw it on my tillering rack while I listened for and tried to determine the exact spot/cause of the ticking, but I did not want to make the problem worse just to find it if a good sinew backing job would shore it up and prevent further damage; I just didn't know whether or not that was the case.  I think I'm going to clean it up some more, put it on the rack, and steel wool it or use gause or cotton to see if I can identify a lifted area.

Once I shorten the bow, I'll heat treat the belly on the reflex forms since I will be applying heat to induce that bend anyway; I don't guess that can actually hurt anything as long as I don't go crazy with it.  Then I'll sinew and hope for the best.

If I don't get any definitive answers on how much sinew to use, I'll just use the same amount I used on my hunting bow, as it seems to have turned out well and is still holding up nicely.

[ssrhythm]

Looking back, I used 3.047 oz or ~86.377 grams.  Bow is 63 is tip to tip 1.5" wide working limbs and recurved with sinew playing out at the start of the static curves.  It worked, but I'm curious to get other sinew backers' feedback.  Is that too little, too much, or Goldilocks "just right?"

[ssrhythm]

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.

[superdav95]

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.

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.