Primitive Archer
Main Discussion Area => Bows => Topic started by: Prarie Bowyer on May 16, 2012, 03:38:54 pm
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So I pushed it a little too far too fast. My tiller was looking good then at a deeper draw not as good. Lower limb stiff and upper limb doing most of the work.
I had that patch on the other bow tha seemed to be working. however I decided to try it again in another suspect place and flat out failed.
So it seems a bit finicky. I'm not sold on it in short.
I have a bow I'm working on for someone and I developed two chrysles. They don't seem to go across the limb and to bow seems to shoot ok. What would happen if I wrapped them in B-50 soaked in super glue and let it go like that? Think I'm asking for trouble? Would it be a good idea to sink a saw kerf into them and fill them with a wedge of something before wrapping?
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I've done exactly as you thought. wrapped it with B-50, and soaked in super glue. Mine has been good since last June. Not saying if it will ever blow, but it seems to work pretty good.
Good luck.
Dmc
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Wait a moment!
I did this torges patch thing on the other bow. that chrysle went completely across the belly. This just goes on the side and in about 1/4" in two places. I'm thinking about sinking a coping saw kerf into them then fitting a little wedge for it to be glued in with Urac or super glue. I don't know why that wouldn't hold. Am I headed for trouble here?
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I suggest finding out why your bows chrysall rather than try to master patching them. Chrysalls are NEVER good, "patched" or not. They only get worse and/or spread out.
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I've only ever had the Ipe and the Lyptus Chrysle. when I got it to full draw with the regular string length I had some more bending in that area than i thought i would. It was fine at 27-28" but I HAD to take it to 29". You know just for saftey sake.
I can't hand select my Ipe. I may go back to Hickory.
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It has to be something in your tillering doing it. Ipe is good stuff and doesnt fret easily no matter the backing. Frets form when its over worked in areas, not many other reasons for them to form on good bow woods.
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Well I sgtart with a loose string then take it back to 29". Shorten the string and work it back to 29". By work it back I get under the bow on my knees and exercise it down with 20-30 pulls down to a screw set at my depth then I hook it over and step back to check the bend. While bending I'm watching the limbs for areas of undue stress.
Then I move my screw down 2" and do it all over again.
I JUST made a tillering gizmo and that helped alot in the early tillering.
When the string is short enought that I need to flex the bow to get it on (I use disposeable string and tie knots in it as I go) I tie up a real string for it. then I work the bow down at a low brace height and try to eaven things up. Then I twist the string to tighten it up and do it all over again.
I try to stop when the string brace height is about right and I can get back to 28"+1".
I use a 50 grit grinding drum for the initial work and a card scraper when I get to the real string stages. When it's where I like it I take it in and serve the string, add a nock point and such, oil the wood, shoot it with poly and make a handle wrap for it.
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Wo what about the patch idea? Think it would work? I would also reduce the opposite limb some.
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Post a pic at 25" draw. I cant say a patch will work without seeing first why its needed.
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shot at 24"
(http://i235.photobucket.com/albums/ee59/scottnlena/IMG_3614.jpg)
(http://i235.photobucket.com/albums/ee59/scottnlena/IMG_3615.jpg)
(http://i235.photobucket.com/albums/ee59/scottnlena/IMG_3616.jpg)
(http://i235.photobucket.com/albums/ee59/scottnlena/IMG_3622.jpg)
(http://i235.photobucket.com/albums/ee59/scottnlena/IMG_3623.jpg)
some at 28"
(http://i235.photobucket.com/albums/ee59/scottnlena/IMG_3623.jpg)
(http://i235.photobucket.com/albums/ee59/scottnlena/IMG_3628.jpg)
(http://i235.photobucket.com/albums/ee59/scottnlena/IMG_3628.jpg)
(http://i235.photobucket.com/albums/ee59/scottnlena/IMG_3621.jpg)
(http://i235.photobucket.com/albums/ee59/scottnlena/IMG_3619.jpg)
(http://i235.photobucket.com/albums/ee59/scottnlena/IMG_3620.jpg)
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Thar ye go!
Just noticed I got them out of order. the ones with a screw driver handle by the tillering stick are at 28"
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I believe you ipe is too thin and your boo is too thick. There isnt much belly wood left to work with boo that thick. I think it will chrysall further. I suggets an all ipe and boo on your next attempt. Perhaps leave the center out to allow the ipe to be thicker. The right limb look spretty flat mid way.
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Yeah what Pearly said. Looks to my eye like you have a flat spot on the right limb just outboard of the chrysal and then a hingey spot just outboard of the flat spot just before the recurve. Whenever I get a chrysal, I look between the chrysal and the tip for problems in my limb thickness taper. Usually means there's a stiffer spot somewhere between the chrysal and the tip.
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i think pearly got it covered, i've never had epe chrysal, it either makes a good shooter or it blows, Bub
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I got creative with the tillering because of centered string issue. I'll reduce it some more. On future ones I'll make the maple core even thinner. I like it in there. Boo is only about 1/8" or so. I sand it down to the action fibers or real close. I do leave it thicker in the center but that is to help fill out hte grip and that section does not bend.
My last recurve had even thinner Ipe.
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If you want that maple to stay I suggest tapering it from center out and let that ipe stay at least 1/4" thick at its thinnest.
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So I just had the same problem. Backed some ERC with bamboo, and ended up with all kinds of chrysles.
Tattoo Dave
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I've had and seen Ipe chrysal sometimes for no reason.It comes from overpoweringthe Ipe, belly wood and the wood itself is not always uniform. Just recently I backed a bamboo backed Ipe bow with one course of sinew because it had lifted a splinter. I shot it about three times and noticed it had chrysaled on both limbs where you wouldn't expect it, right at the Fades. I'm still shooting it and it hasn't broke yet, but,,,?
There are different grades of Ipe and the small pin knots are very hard to see. When you have a small knot it doesn't take much to chrysal or break one.
I'd say wrap it, soak it in super glue or, wipe the spot down real good with oven cleaner or acetone and heat it lightly and feather some super glue in the crack and shoot it.
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Just thinking here, but I'd say that wrapping and supergluing won't do much to help a bow that is chrysling-here's why I think so:
Chrysleing is caused when the back overpowers the belly and you crush a line of belly cells. Its like an intense dose of set in a small area. Fibers and glue won't replace crushed wood cells. It might help protect the back from breaking (which could happen if the belly was too weak), but it won't reverse the damage done at this point. You can't add stiffness back to the belly of a bow without a wood patch and I have considerable doubts about the wood patchs (but thats for anothe post).
I've had bows that chrysled (especially locust) and still shot for years. However, Pearls right, it always gets worse over time. Just my 2c.
Gabe
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I think I would scrape out the chrysal and glue another slat of ipe on the belly, then retiller. A chrysal is not like a broken bone, it won't heal.
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The bow chrysaled because it's bending far too much into the handle on the right hand limb.
If your bows are chrysaling it's because the belly is being asked to take too much compression.
As mentioned before chrysals almost ALWAYS have a stiff spot between them and the tip.
I would suggest slowing down and not using a 50 grit drum....
Rasps/files/scrapers and sandpaper are your friends!
Ipe can take a hell of a lot of compression BUT ONLY in a bow that is well tillered - put it on the belly of a bow with hinges and it will chyrsal just like any other.
The first thing to do with a limb that has chyrsaled is to look tipward and remove the offending stiff section. DO NOT touch the chyrsal unless you are going to do a proper patch. If you just cut a small kerf and fill it then the CAUSE of the chyrsal is still there. Wrapping a chrysaled section of limb is going to do absolutely nothing other than hide your mistake....
Good luck.
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If you want that maple to stay I suggest tapering it from center out and let that ipe stay at least 1/4" thick at its thinnest.
Maple is double tapered on both sides. Thickest is 3/16 in the center and just under 1/8" at the tips.... I think.Somethign like that.
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I've had and seen Ipe chrysal sometimes for no reason.It comes from overpoweringthe Ipe, belly wood and the wood itself is not always uniform. Just recently I backed a bamboo backed Ipe bow with one course of sinew because it had lifted a splinter. I shot it about three times and noticed it had chrysaled on both limbs where you wouldn't expect it, right at the Fades. I'm still shooting it and it hasn't broke yet, but,,,?
There are different grades of Ipe and the small pin knots are very hard to see. When you have a small knot it doesn't take much to chrysal or break one.
I'd say wrap it, soak it in super glue or, wipe the spot down real good with oven cleaner or acetone and heat it lightly and feather some super glue in the crack and shoot it.
Great. I just got a new Ipe board. It has two worm holes in it, 3-4 pin knots in it, and a big dutchmans plug in the middle. The plug I'm less worried about becasue Torges says you can use those to fix wood before it's used. Still I'll place it in the riser section of the next bow. On this bow I'm going to try the saw kerf idea. I don't know why it wouldn't work. The torges patch works well and if you think about it it shouldn't work at all. You have two mated semicircles. A male and a female. The female is flexing against the male such that it pinches the plug and thust pushes it out. That can't happen here.
I've shot the bow a fewtimes and drawn it to 28 and 29" on the tree and they don't seem to be growing. I'm thinking it's like those cracks on a car window. If your relieve them they'll stop creeping. Filling in with an Ipe wedge that is well fitted should almost dissapear. I nkow Horn is AWESOME in compression and I could fill it with that but it would be an obvious patch.
There was grain runout across the belly and that creates the twist when drawing. Took some fiddling and luck to get it all out. Next time I'll wait before cutting in the arrow shelf. It's a pain because the twist showed up late in the process. Probably the outer portion of the limbs could be bending more so I reduced them.
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The bow chrysaled because it's bending far too much into the handle on the right hand limb.
If your bows are chrysaling it's because the belly is being asked to take too much compression.
As mentioned before chrysals almost ALWAYS have a stiff spot between them and the tip.
I would suggest slowing down and not using a 50 grit drum....
Rasps/files/scrapers and sandpaper are your friends!
Ipe can take a hell of a lot of compression BUT ONLY in a bow that is well tillered - put it on the belly of a bow with hinges and it will chyrsal just like any other.
The first thing to do with a limb that has chyrsaled is to look tipward and remove the offending stiff section. DO NOT touch the chyrsal unless you are going to do a proper patch. If you just cut a small kerf and fill it then the CAUSE of the chyrsal is still there. Wrapping a chrysaled section of limb is going to do absolutely nothing other than hide your mistake....
Good luck.
Yea it's frustrating because it was looking pretty good. Then I tackled the the twist and went to the final string. I had it to 26-27" with no apparent problems and started scraping to clean up and getting it down to 28-29" It was the trip to 29 that killed it. I've already reduced the outer limbs and will be trying the saw kerf. Mostly as a way to visualy fix the flaw.
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Prarie try a few reflexed only or straight bows until you get it ironed out, then maybe head back to the R/D's and give it another whack. You have a reliable, solid combo.
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Well I sgtart with a loose string then take it back to 29". Shorten the string and work it back to 29". By work it back I get under the bow on my knees and exercise it down with 20-30 pulls down to a screw set at my depth then I hook it over and step back to check the bend. While bending I'm watching the limbs for areas of undue stress.
Then I move my screw down 2" and do it all over again.
I JUST made a tillering gizmo and that helped alot in the early tillering.
When the string is short enought that I need to flex the bow to get it on (I use disposeable string and tie knots in it as I go) I tie up a real string for it. then I work the bow down at a low brace height and try to eaven things up. Then I twist the string to tighten it up and do it all over again.
I try to stop when the string brace height is about right and I can get back to 28"+1".
I use a 50 grit grinding drum for the initial work and a card scraper when I get to the real string stages. When it's where I like it I take it in and serve the string, add a nock point and such, oil the wood, shoot it with poly and make a handle wrap for it.
This advice may be unrelated, but it will definitely affect your tillering, which may be what is deceiving you. When you're tillering, you want to get your bow to low brace as soon as possible. If you are drawing the bow to 28 or 29" before getting to low brace, then either your tiller string is way too long, or you're just waiting to long to shorten it. The tiller string initially should be just long enough to reach from knock to knock. Then as soon as your limbs are moving enough to get it to low brace, shorten the string. Tillering the bow out with a long string on it does nothing to show you the true forces that will be exerted on the limbs with a regular string.
I'm not sure what you are using for your disposable strings, but you may want to consider making an overly-long flemish string out of b-50 with a loop in one end, and an adjustable bowyers knot in the other. Then you have one string that can be used on many bows.
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It worked! I was able to draw and shoot the bow. I put it on the tree to look at the limbs. No problems were evident. Had it at 28". Decided I should reduce the outter thirds of the limbs for saftey sake and when I went to take it off the tillering stick that 1/4" extra draw to get the string off the peg caused my most dramatic bow explosion.
I"m not working in a good place lately. I'm screwing up alot of bows. I'm gonig back to Hickory for a while. Ipe is over rated or not for new bowyers.
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Your designs are not for new bowyers. Ipe is wonderful wood.
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What is wrong with my designs? they have all worked well in Hickory. I wish I could quantify exactly what I am doing wrong.
I buy 3/4" thick Ipe and rip it in 1/2 after cutting my rough blanks out. The edges of the board are radiused. So that gives me 4 bendy handle bows (other wise there is a cove or I need to trim the radius of and waste wood. I try to make up the difference in thickness for the draw weight I hope for in a core lamination of either maple or bamboo.
Lately I'm trying to wrok fast and just get them done. figure things out so I can eliminate the discovery in the process and get close to final tiller and shape.
On that one it was probably a recurve mroe than a R/D bow becaue the tips were above the center at rest. I figured some string follow woudl pull it back down.
I've had a few glue up problems with wood pulling down to my form despite my wedges and thoughtful rubber band placement. I may need to make a dedicated form for these. I hate those long flat parts in an otherwise curved limb. Had rubbers break in the form and wind up with one recurved side and one barely reflexed side.
Latest bendy handle recurve I got the tips out of alignmant at glue up and I shaved the belly to thin to start with. I have generaly pretapered my belly to help get them in forms. In the case of a recurve I need to cut the kerf also. I was struggling to mark and saw along that radiused edge. Bugger me.
I can feel the emotional state from which the mistakes come from.. But as I work on more bows and will myself to come up with a great one.. it's like it fated to go wrong.
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Here comes honesty. I remember your joining in around here and thats awesome! You chose a great hobby to start up. Your new and jumped right into tri-lam R/D bows before you ever learned to tiller or build a just a 'bow". Your design of chose is one thee toughest to tiller and glue up as shown by your above pics. Changing back to a more resilliant wood doesnt teach you anything about tillering or buildng, it just makes a poorly tillered bow not explode. Learn to build simple bows with reliable wood and expand upon that with bamboo, tri-lams, recurves and horn. Hopefully this doesnt come across as pompus or rude, truly not my intentions I swear. Your questions where clearly answered above and you want to blame the wood, thats simply not the case. Your talented and "get it", thats obvious. Slow her down a bit and let your skills catch up with your imagination. You will build kick azz tri lam recurves one day.
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I agree with a lot of what Pearlie just said. I too remember when you first joined us. I was just a beginner myself (and still am!) and I remember seeing you turning out these bows and thinking, wow, this guy's hardcore! It's obvious that you like to challenge yourself, and some failures and disappointments are bound to come from that. You just have to soldier on and try to make the most from the experience. These guys here can teach you a lot, if you're willing to listen.
I've never attempted a tri-lam reflex deflex, so you can take this with a grain of salt. But if I was you, I'd try making the limbs slightly wider to better handle the draw weight you are looking for. I would narrow (or remove) the maple lam and thicken the ipe. I would also invest in a pully setup on the tiller tree, rather than using a tiller stick, to keep the stresses on the limbs to a minimum. My bow building mentor always told me "the tiller tree is a harsh mistress". If that's the case, I can only imagine that a tiller stick would be nothing less than a cold hard bitch ;)
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i had missed the whole second page of this thread n wished i hadnt...anyways...
your pics tell the whole story and dont need any words to go along with them
#1. it looks like your ipe got to thin on the belly....either make the maple thinner or the boo thinner or both,and if the ipe starts getting thin then you need to start side tillering
#2. its very easy to see from your tiller pics that you grossly overdrew that bow while tillering,and the combination of my first explanation and this will fret the best compression woods everytime
mike and pearl are giving you very sound advice
patching,wrapping those is a waste of time imho...those frets are right at a high stressed spot(fades) and go all the way to your glue line with the maple...that ipe is toast man.....the best way to fix that and get a shooter out of it is to grind that ipe off and thin the maple some and glue another compresion strong wood slat on the belly(i.e. ipe,osage,yew etc..),and if you have room to narrow it id suggest that as well.
and i agree with drums about taking a few steps back and get some more simpler designs under your belt,and get some confidence in ya,otherwise its no fun and youll get so frustrated that youll stop trying to make bows altogether....i say this because of my own experience,and i went thru a couple years of trying to build bows that were over my head,and i almost stopped building bows...whew...glad i didnt do that,and im glad i went to trying way easier stuff because it gave me some confidence and made it fun instead of frustrating
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I'll take a good piece of ipe over any other belly wood in a laminated bow, Period. All ipe is not created equally however. I'd start by making sure you choose good pieces of ipe. If you're having someone else choose your wood, I'd start by fixing that.
I must buy it mail order.
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I thought of something later while on a walk. I took that bow unwrapped and cooke dit for 4 hours last night at 150* with another bow I was gluing up. When it exploded it was the other limb. COmpletely no warning and at 28" AFTER arleady removing some wood from both limbs out near the tips.
the piece that came of came off along the URAC glue line and it came completely free. I wonder if I damaged the glue or dried out the wood and needed to let it rest to get the MC back up?
Thanks for the input guys. I'm continuing witht he tri lams. I've had them work barring the broking form strap failures.
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That must have been it then.
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"this feels great and is soooooo much fun"
(http://i1181.photobucket.com/albums/x436/blackhawk28/ispc026073.jpg)
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the most telling statement you made was"I'm just hurrying and trying to get them done", that's a poor philosophy when building bows, that's why i hardly ever build a bow for money, i don't like to rush, and i don't like to be rushed, just step back, take a breath and K.I.S.S., ;), Bub
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Yea,
I'm not building from a good place. I tried to get all my stuff laid out and error free for these after several successful ones. then I introduced new variables that cause problems.
I'm liking the bendy handle bows. I've got one straight one at 60" going. It's coming along nicely and the "Tillering gizmo" seems to be working like a charm. I wonder if that thing works well on R/D bows. I wouldn't think so.
That exploded one was also pretty deep. NOT as deep as previous ones. But I had my tips above the high point of the center at the riser. I think I should have added spacer blocks under it.
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:D yeah a gizmo doesnt fair well with R/D designs...like cam said you need a rope n pulley tiller tree....i never use a gizmo or straight edge anymore...its all done on the rope n pulley,no tiller sticks.....you will be able to see it unfold waaaaay better on a tree than a stick,and you cant see it well enough being underneath it while on your knees pulling it from a stick....
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Well I loop it over the peg and step back. Probably I should try the rope thing again. I felt like physicaly moving a peg forced me to not push too far too fast but perhaps It only made me do it in a different way. I also felt like watching the limbs bend I could see the fibers compressing and stressing.
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Tillering stick = wood grenade ;)
I second what has been said. KISS
If you were ready to start selling these bows you wouldn't need to ask all these questions.
I would kindly suggest you take a step back and think about what you are doing. You are asking questions about things that should be completely sorted and well 'worked out' for somebody who sells bows.
Making bows is NOT an easy way to make money and you should remember that if a bow breaks whilst at full draw it's only luck that stops the person holding it from getting seriously hurt.
The overall quality of ipe is going down due to the way it is being used and grown today. I have it on very good authority that this situation is only going to get worse...flooring boards are made from quick grown wood (eg.cheap) nowadays. I'm not saying it's all bad but the proportion of not too great ipe is going to get higher. Try looking at greenheart.
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When I look at the full draw pics to me it looks like you have to much reflex in the handle area. With the extreme radius in your handle it is putting a lot of stress on the limbs right out of the fade. It would be difficult to get the limbs to bend smoothly out of the angled handle section. If youare set on the design then I would try to use les reflex in your handle next time. That will make it easier to keep the limbs "flowing". I looked and looked at the pics and while you do have a stiff spot about mid limb, I think the real problem lies in your design. Like everyone said ipe can take alot of strain and tiller imperfections. The thick boo, stiff spot in tiller and mistake In design all added up to frets. Take a look at your handle and I think you will see what i mean. Good luck on the next one.
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You know what happens to me is that when something happens I loose my confidance. I start second guessing myself or revisiting things I thougth I knew.