Primitive Archer
Main Discussion Area => Bows => Topic started by: rockrush69 on September 20, 2013, 02:20:06 pm
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Hello what's going on guys? I have a bow that was already back with sinew about a year ago .... it is made of hickory and its kinda light in weight ... my question is ... if i add more sinew now after it is and has been already backed with sinew will that raise the draw weight of my bow ? I would like to go from aroumd 35# up to 40-45#
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I don't see why not.
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If done right sure...but that's the key words....it must be evenly applied and same amount to both limbs,so yo don't have to retiller much if any at all....if your sloppy about it you will have to retiller and lose any weight you gained negating any benefits....and a sinewed hickory would be my last choice of bows to hunt with and use in Florida(jus my two cents there)
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I know ... its a backing wood with backing on it ... lol. ... it was one of my first bows from a few years ago . And its my dads and he wNts it heavier. So ......
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I think it's more because Hickory and sinew both work better in low humidity. Hickory needs lower moisture content than most woods to perform well, and sinew expands/relaxes in moist air.
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Yep just start another..... ;)
Sinew actually has very low stretch resistance meaning that you would have to add a large amount to get a 15# raise in weight.....trust me you would need close to 100 grams in my experience. Sinew/glue is way heavier than wood 1.3sg this combined with the low stretch resistance would likely just make your bow sluggish.
In the time it takes to shred all that sinew, apply it and then let it cure (a couple of months at least) you could have made many more self bows! Heck I reckon I could knock up a 50# selfbow in the time it took to just shred the sinew...... :)
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Original Question....
Backing of most any kind doesn't raise weight much at all. Good for preservation, i.e. less chance of breakage or raising a splinter.
At the weight you are currently at...Make a new bow as mentioned earlier.
JMO
Ron
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How long is the bow n-n and what is your dad's TRUE draw length,maybe you could pike it that will add weight quicker than sinew and not add mass weight,not to mention much easier. ;) ;D ;D
Pappy
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Backing will raise draw weight if you put the proper amount of reflex to it as you do it.The more reflex,the more energy storage.Putting sinew on a reverse profile to make it do it's fair share of the work in otherwords,and use hide glue please.You should see the difference.At this stage of your bow piking or a new bow would be faster as said earlier.
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Its an old bow . And it has been finished for a long time. I already added sinew . And processing and glueing sinew on only takes me maybe an hour . ( not including dry time ) its my dads bow and only gets shot every few months . I had tons of sinew so i went ahead and just added a thick cable of sinew down the center of the back . As to raise it in the middle and make it a little more arrow dinamic . Also had some compression cracks on belly so i wrapped it on both limbs ( just for looks only top limb needed it ) now it will sit for a while ... maybe three or four months . And it only had one layer of sinew before. So .... i dont think another layer would hurt . But we will see . Rather than cuting it down to make it shorter ... i will just leave it alo e at this point and make him anothrr one ... i am going to cut down five mulberry trees today ! So .... i will have some bow wood soon . Thanks for all the tips guys ... as always i habe learned alot from the masters . :)
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would cuting it down in length be an option?
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Naaaa ... its a finished bow . And because of it already being sinew backed and seasoned for a year . I added more waited a month ... and shot it yesterdY ... it did raise the wieght alot . From 35# to 55# im very happy with the turn out . :)
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Just my opinion, take it for what it's worth, but living in Florida I wouldn't waste the sinew or use hickory for anything but BBQ'ing pork ribs. My first hunjting bow was hickory, 70#. I've seen it shoot like it was 35# by 10 in the morning when the Temperature and humidity really started kicking in gear.
If I backed it with anything it would be Bamboo.
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+1
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I dont know ... maybe its thw poly urithain that i seal my bows with . But i have 2 hickory bows one with sinew one without. Both shoot every day and have nevet had a problem. And im on the gulf pretty much as far south on the west of fl. You can go .. very humid here. Idk . Maybe i just lucked out . :) as for sinew . I have a hook up ... i have way more than i know whT to do with .... but i fou d a few folks on here that wanna trade some sinew for chert so finalyy i can put all this stuff to use . My butcher friend gives me about 40 leg tendons at a time every few weeks.
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Correct me if I'm wrong but isn't Polly water proof? I'd think it would effect the curing time of sinew as it would seal it off from oxygen too soon. But hey to each their own. As to draw weight increase the answer is yes. A properly layed course of sinew can raise it by 5-10#.
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Poly is water resistant, and it does slow the curing process. I've had to retiller some bows with sinew overtime that were not sealed with polyurethane.
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Nothing will prevent sinew or wood from changing M/C as the R/H changes. Both are hygroscopic and that means they take on and release moisture to the atmosphere as the R/H changes.
My Massey Medicine Bow(sinew backed hickory) has changed weight from 45# to 65# depending of the R/H at the time. That bow was sealed with Massey finish(2ton epoxy thinned with acetone), 5 coats of Tru-Oil and a spray of satin poly.
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Thanks for the info. I know of some who apply sinew with TitebondII and III and as a protective backing I see it as fine, but I much prefer hide or sinew glue and then set it aside to cure for a time then maybe sealing it with something water proof. When you think of it the birch-bark wrappings done on the ancient bows and even the snake skin were water barriers. :)
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I have so many bows that have been backed with sinew its rediculus and 2 of them are hickory . I have never wieghed them during moist and dry times. But i have never noticed a change. Looks like im gonna need to check on this ... i definatly belive you . Because number one hickory and si ew both suck water up like crazy . And number two . Well .... you guys are respected members of this site . Who are very good bowyers . And yes . Poly slows down the process . But nothing really totally seals anything period ..... im sure it may help with the moisture changing the bows weight from day to day though . As it slows this down ....
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Can u seal the sinew with a layer or two of super glue
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I took Pat's Medicine bow hunting one morning near the Kissimmee River and shot a hog with it. No doubt it was shooting in the 60# range. By afternoon with the temperature and humidity climbing I had to park it for the Benelli. It was shooting my arrows to inconsistently to hunt with.