Primitive Archer
Main Discussion Area => Bows => Topic started by: kevinsmith5 on November 09, 2013, 10:17:31 am
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Once again as part of my "horsebow without horn so you don't get to use glass" argument I'm looking for experience folks have with doing a sinew backed bow where the sinew was both waterproof and the bow was durable. The more ways, more examples the merrier. As an ELB guy and only so far making Flatbows for kids I've no experience with sinew, so if the answer is "can't be done" feel free to say so.
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You will never completely moisture proof any wood bow, sinew backed or not. I use Tru-Oil on all my bows and get good protection from it., plus it is easy to repair if necessary. My sinew backed bows will get mushy in humid, moist weather. When the humidity is high I don't use these bows and keep them stored in a dry location.
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Birchbark with Epoxy on top of the bark.
(http://i399.photobucket.com/albums/pp78/pat_05/IMG_0884.jpg)
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I do usually use snakeskin or rawhide over the sinew then seal over them.
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That's sweet pat, kool look to the bark
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Could you just epoxy over the sinew? Do all of you glue the sinew down originally with hide glue?
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Yes, you can just Epoxy over sinew. That's the method Jay Massey used. Massey diluted his Epoxy considerably before application but that's unnecessary and you'll get even better waterproofing by omitting the dilution except for a couple of drops of lacquer thinner.
If you want your sinew to do real work, you'll use a collagen based glue.
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I've used Knox for sinew but with mixed results. Now I only use hide glue.
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What could possibly go wrong with Knox?
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I've always thought that Knox was just purified, powdered hide glue.
At any rate, I usually save all of my finely shredded sinew scraps and make glue with them on the spot by warming them in a small amount of water when it's time to back a bow. That way the sinew (or hide) glue isn't heated multiple times, which I think reduces its strength.
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Pat, I had the sinew lift from the limb on two bows when I used Knox. It could have been my screw-up but I switched to hide glue and haven't had a failure or sinew lift since.
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For you that save the hide glue for later use, can it just be refrigerated or do you need to freeze it?
I processed some lately from my sinew and rawhide scraps and put in a covered plastic container in the fridge.
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The birchbark with epoxy looks very nice.
But I have to ask, are you speaking about the performance of sinew
If you want your sinew to do real work, you'll use a collagen based glue.
if so, why do you think epoxy is inferior?
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Nobody suggested actually backing the bow with sinew and epoxy. The reference was to PVA type glues.
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well, hide glue and sinew are chemically identical. so you get an incredibly strong, tough, close bond.
Hide glue is collegen. Sinew is collogen. Both soften in water. epoxy just so happens to be hydrophobic.
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I've used Titebond III (waterproof) with sinew and the results are very springy and water beads on the surface. Just use the Titebond III like you would hide glue: size the wood with it, use plenty of glue with slightly damp or dry sinew, and put a layer of glue over the whole job when the sinew is dry. Not primitive but it works.
(I'll probably get flack for this but, yeah, I said slightly damp or dry sinew. IMO, too much water messes up the job.)
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kevin.....It's just a matter of putting waterproof barriers between the air and your sinew backing.TT3 with a snakeskin then varnish over that[that's 3 barriers] or epoxy and birch bark with varnish over that[that's 3 barriers too] is about the best that I've been able to do.I've personally hunted with a sinewed bow in light rain off and on with no ill effects,but I would'nt reccomend staying in a hard rain with it.I keep mine stored in the house dry too like Pat B.Here's my sinewed epoxy birch bark bow too.
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Try dip sealing a sinewed bow once. Its incredible, and very, very effective. I use a 4" x 42" PVC tube with Helmsman satin. Nothing goes unsealed, and heavily sealed at that.
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snakeskin
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snakeskin
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I bet it did PD...I worry mostly about the back though where the sinew is on.I've had my sinewed bows out in the high humidityand heat along with misty weather.Not all day mind you but for 8 to 10 hours a day with no ill effects.There's no getting around the eventual creeping in of moisture if it's left out there long enough,That's just a fact.
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I havent tried this, and I doubt it is as effective as the Massey finish or others, but I have read somewhere that smoking a sinew backed bow helps make it resilient to moisture. Like smoking braintan buckskin, the formaldehyde imparts some moisture resistance.
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Yes Carson I've read and heard the same.Tying the bows up abve the fire in the teepee.I know a film of smoke I would call kreosote would develope over the bows and that sure is waterproof.It's sticky at first then dries to be easier handled.I've even discussed making the glue with tannic water from soaking oak bark etc.but have never tried that either.Maybe at the classic when I have my lodge set up it could be done smoking a newly sinewed bow.
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Ok along the lines of the snakes skin- could I rawhide over the sinew, gluing the rawhide down with TB3? For this "hey that looks like a horn bow but there is no horn" idea I think the skin wouldn't look as medieval as rawhide (remember this is a debate with an SCA member, it's as much about looks as anything else).
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Composite bows were often covered with leather, rawhide,gut and even snakeskin during medieval times.
However I think you are putting too much overall effort into a prop idea.
I would follow the plan for the bow that Dauntless just posted and dress that up with faux rawhide/gut(brown paper with Epoxy) and use an Epoxy with pigment to duplicate horn on the belly.
Here is an actual composite bow from that period. This one happens to be entirely wrapped with a spiral wrapping of bark that completely covers any evidence of horn.
http://www.bing.com/images/search?q=Zargalant+bow&FORM=HDRSC2#view=detail&id=05D723AB82580F93047746807668012D42E760D6&selectedIndex=0
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It's not really a prop. It's for actual use in a target archery competition. I n debating what bows could be used in "period archery competition" the horsebow shooters pitched a fit over there being a rule against FG or carbon cores because they swore a horsebow made without FG would cost "$1200 or more" (they said that a bunch). So while all other styles would have to shoot all wood bows, they should be allowed to shoot FG. I'm out to show that's not true.
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I understand that. I just meant the prop aspect of looking the part. It shouldn't be hard to show them that a non-glass replica can be made for a few bucks plus time invested.
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shellac is traditional way. I use directly on sinew.
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Another traditional finish is called French polish. It is a mixture or alternating layers of shellac and boiled linseed oil.
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Fish skin, snake skin, bark, but nothing is tougher than rawhide and sturgeon skin. Those are the 2 most durable in my book, add 9 coats Tru-oil. And I have no problem hunting in downpours.
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Downpours are usually not the problem, its high humidity that affects our selfbows and sinew backed bows. Some woods are more susceptable than others but sinew and hide glue are very hygroscopic, meaning they take on and release moisture as the huidity changes...even when well sealed.
I made a copy of Jay Massey's Medicine Bow; sinew backed hickory with a rawhide covering. I sealed this bow with a layer of Massey finish(2ton epoxy thinned with acetone), 5 coats of Tru-Oil and a few sprays of satin poly. That bow can change draw weight by 20#, depending on the humidity.
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Yep:)
I hunt the coast range of Oregon humidity rarely drops below 70%
My sinew backed yew only various about 2 pounds.
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I would expect epoxy glued and coated sinew to be water proof and probably superior to hide glue adhered sinew. The same for sinew glued with Titebond III and coated with polyurethane. But, epoxy, Titebond III or Polyurethane are not primitive materials. They are not illegal, immoral or fatening, so it depends on how primitive you want to be. You will also get superior performance from fiberglass or a compound bow, so each of us needs to draw our own chosen red lines.
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Those are the rules PA states dxhound.Everyone on here knows that.As far as primitive goes your right each can go as far as they want but leave the working parts that do the work natural.This is not a legality or moral or health food site.To jump from TT3 or epoxy usage to compounds is quite a jump.Most on here don't live a primitive life style either.If they did they would starve.Personally I have running water and do use electricity most times.I heat with wood alone.No back up.How primitive are you?
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I don't think anyone expects Epoxy or TB glued sinew to be superior to hide glued. Epoxy won't even work and nobody has ever shown that TB works as well as hide glue.