Primitive Archer
Main Discussion Area => Bows => Topic started by: Badger on August 07, 2015, 11:45:23 am
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I have primarily used dry heat for bending osage on all but the tighttest curves. Seems like the last couple of years I have had more problems with cracks forming in the bend, or uneven bends, or the wood just not want to give. No problem on the gentle curves like you would see on a cawl or d/r bow but on the recurves. It has got to be something I am doing different.
The only difference I can figure out is that I used to buy almost all my wood from the southern U.S. Last few years I have been buying from Ohio, Michigan, Pennselvania, I like the wood a lot better.
Is it posible that where it is grown affects how it bends?? 90% sure it just my fault but I can't see anything I am doing different.
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Steve the two things I believe cause cracks in osage with dry heat are, wood not totally dry and/or too much heat being applied that it tears the wood rather than stretch it out like we want it to. I wont lie, I got tired of dealing with and the last few years all the osage bows Ive made have been straight tipped, or statics.
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I never have been big on recurves I like a gentle flip in the last 12" or so but have even experienced some mild cracking there. I won't even attempt a dry heat recurve anymore. You may be right about the greenwood, most of the wood I have been working with lately has been fresh cut within the last couple of months.
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That's probably your killer. Even though its dry enough to make a perfectly serviceable bow, its not dry enough to suck up intense heat. I think a flip tipped long bow is one of the sexiest profiles in the self bow world, but I really cant get one to shoot much differently than a straight reflex limb with very little set. So I keep it simple anymore.
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Normaly what I do is as soon as I get a stave in the mail I rough it out into a bow, about a week or two later I put in on a cawl and then I wait about a month to tiller it out. They usually ride around in my car for about a week before tillering.
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I have run across the odd Osage that was resistant to heat bending Steve and it's usually wood with tight rings. I always use wet heat except for making corrections or reflexing, just safer.
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I've used your localized steam method a few times Marc. If that method wont move wood, it doesn't want to move.
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I have run across the odd Osage that was resistant to heat bending Steve and it's usually wood with tight rings. I always use wet heat except for making corrections or reflexing, just safer.
The stuff I am buying up north generally does have much tighter rings than I used to get down south. That might be the problem.
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On Osage when I'm doing heat corrections I always use oil now. I've been having too many problems with just dry heat and breaking rings.
Just wanted to add almost all my Osage dead standing with very tight rings
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I too use marc's localized steam method for flipping and recurving with great results!
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I've done a few tight radius statics and I'm working on one now..........with dry heat, I think slow medium heat works best with me. Too hot too quick is not good. I've done some steam bending on osage too with real good success and the steam temp is only around 212 deg F.... not real hot but deep penetrating. My wood is 4 or 5 year old, and the ring thickness varies........
DBar
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could someone link too a post or describe this localized steaming? i haven't heard of it before.
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I've used your localized steam method a few times Marc. If that method wont move wood, it doesn't want to move.
Is there a how to on this stem method ??????????
Thanks
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I think the process they are referring to is to wrap a localized area with a wet towel/rag and seal with aluminum foil. then hit it with the heat gun and apply pressure with clamp. for me this method works very well taking out twists and bending thick handles to align the tips. I agree with danzn bar, dry heat seems to cause cracks for me when it is rushed. For me dry heat seems to work best combined with vegetable oil and a light, steady pressure as I bend around a form. When the wood is ready, it bends like melting plastic. If I push too hard or force it, I get cracks. Most have been shallow, though and I leave enough wood usually to just scrape below the splinter to good wood.
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I live at 7000 ft,, I was used to steam bending at sea level,, when I moved here it seemed more difficult to make a bend without problems,, it takes food longer to cook,, so I think it just takes more time to get the right heat for the bend,, or longer steaming,,
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I live at 7000 ft,, I was used to steam bending at sea level,, when I moved here it seemed more difficult to make a bend without problems,, it takes food longer to cook,, so I think it just takes more time to get the right heat for the bend,, or longer steaming,,
Just longer penetrating heat in general....steam or dry heat.......for osage :) ;)
DBar
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The localized steaming method is in a back issue of primitive archer
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I think the process they are referring to is to wrap a localized area with a wet towel/rag and seal with aluminum foil. then hit it with the heat gun and apply pressure with clamp. for me this method works very well taking out twists and bending thick handles to align the tips. I agree with danzn bar, dry heat seems to cause cracks for me when it is rushed. For me dry heat seems to work best combined with vegetable oil and a light, steady pressure as I bend around a form. When the wood is ready, it bends like melting plastic. If I push too hard or force it, I get cracks. Most have been shallow, though and I leave enough wood usually to just scrape below the splinter to good wood.
Yep.....Saw Pearly do it at Marshall on Jackson Cash hockey stick..........
DBar
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The temp water boils is 212 @ sea level and drops by roughly 2 degrees per 1000 ft of elevation,so in brads case water boils at 198 degrees storing less energy. Boyle's law,there fore I believe I tight wrapping of foil raises the pressure ever so slightly making the steam hotter if that makes sense lol!
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Steve, are you referring to cracks across the grain on the outside of the bend or longitudinal cracks(checks) in the back at the curve? I have had osage crack across the grain while bending dramatically with dry heat. I use oil on the area I heat and bend and that helps in bends that are not too drastic. I think the oil holds the heat better, helps it penetrate the wood better and prevents scorching. I also use shellac on all newly exposed backs, no matter how well seasoned it is. The shellac is quite stable even when getting the belly very hot and has prevented any checking on the back that is caused by the heating, drying of the wood.
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Pat, I am referring to cracks across the bend actually breaking the wood, usually it doesn't go past a ring but I have ruined a few bows with them actually breaking.
I never noticed this with the southern wood and it might be because of the fatter rings. I have gotten to wear I really prefer the more northern wood but I just don't attempt dry heat recurves with it anymore.
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On my last osage static recurve "Sweet Thang" I made drastic recurves with dry heat and it cracked badly. It was from Clint's monster osage tree from Illinois and it had very nice rings. I ended up filling the cracks with super glue and adding underlays and so far all is good. The under lays were yew with a thin piece of ipe where the string tracked.
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I use steam on recurves [ don't do many of them anymore]and dry heat on most everything else, but my rule is any Osage less than 2 years old I steam first and older I use dry heat. :)
Pappy
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That sounds like a pretty good rule Pappy.