Primitive Archer
Main Discussion Area => Bows => Topic started by: Badger on June 04, 2015, 12:57:58 pm
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I use a cawl on all my osage with heat. I have had the occassional crack appear when the moisture has been too high. The piece I am working now I thought to be dry yet I did get a small crack that I am not worried out. I have to wonder now if the wood doesn't have higher moisture than I thought it had. Anyone else ever have a crack open up on dry osage when heating. The crack was not there before heating.
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A bunch of times. I keep superglue handy and hit the crack when it first appears no matter how small. This always stops them and they tend to be invisible on a finished bow.
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I do the same as Eric. I also seal any newly exposed back with shellac, no matter how old or dry the stave is.
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More often than not for me, but I seem to gravitate to the staves that require more correction.
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I do the same as Eric. I also seal any newly exposed back with shellac, no matter how old or dry the stave is.
+1
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Steve it has to be "wetter" than you perceive it to be. No other reason I can think the osage would rupture like that. Ive had it happen plenty of times myself.
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I've had 20 year old staves crack while reflexing them.
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20 years old doesn't always mean dry though. If a 20 year old stave is stored in 70% humidity for a month its not dry enough to work.
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I am kind of like Pearl, it never surprises me when the moisture is in question. The bow didn't take any real set as I was finishing so I went ahead and finished but I am going to stick it in my car for a couple of weeks and see if it gains weight before I do the finish work on it. The crack closed up once it cooled down and is barely visible if you are looking for it. Going to give it a touch of superglue and forget about it.
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Its similar to how we can rough out a green stave and have it dry in 2-3 months. Its all about the humidity it lives in.
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Years ago we had some abnormally dry weather, bluebird days with very low humidity. I had some seasoned osage staves in my garage, to my horror, when I looked at them they were riddled with hairline cracks down the backs. I thought they were toast but looked at them again several days later and I couldn't find the first crack, they had all closed up with the return of normal humidity. This was before I learned to shellac my staves.
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This one only opened up slightly on the belly side. My bows usually settle in at about 8% in my coastal california climate. I can live with that pretty well. Humidity runs about 50% but slightly drier indoors.
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This one only opened up slightly on the belly side. My bows usually settle in at about 8% in my coastal california climate. I can live with that pretty well. Humidity runs about 50% but slightly drier indoors.
Do you find 8% MC too low for some woods?
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I haven't experienced that as a problem. I've had very, very few develop cracks when heating to make corrections. I use no oil or crisco or anything.
I try to do the major corrections while they're green, with steam. When they're dry, I use the heat gun. But you guys are really making me wonder what I do differently than you... maybe I heat slower, or dont get them as hot? maybe I've just been lucky :^)
I live in western Pa, one of the cloudiest and rainiest parts of the country. All of my wood is in my garage or shop. I do keep staves I'm working on in my drying box. In my shop now I have a dehumidifier running, so things are fairly dry and stable there in spite of what's going on outside.
I don't ALWAYS re-seal the stave's back after exposing a new ring. If it feels dry, 'rings out' sufficiently while bouncing
an end off the cement floor, or reads dry with my moisture meter, I don't shellac them and they're just fine... again though, maybe it's the relatively stable environment. Not sure why, but cracks while heat correcting, reflexing, or recurving hasnt been a problem for me.
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Considering how many osage bows I have built I would say I have had very, very few develop cracks when heating or storing. I never seal the back once I have roughed a bow out unless I know the bow to be green. If a stave is 6 months old I feel pretty confident in roughing it out and not sealing.
I haven't experienced that as a problem. I've had very, very few develop cracks when heating to make corrections. I use no oil or crisco or anything.
I try to do the major corrections while they're green, with steam. When they're dry, I use the heat gun. But you guys are really making me wonder what I do differently than you... maybe I heat slower, or dont get them as hot? maybe I've just been lucky :^)
I live in western Pa, one of the cloudiest and rainiest parts of the country. All of my wood is in my garage or shop. I do keep staves I'm working on in my drying box. In my shop now I have a dehumidifier running, so things are fairly dry and stable there in spite of what's going on outside.
I don't ALWAYS re-seal the stave's back after exposing a new ring. If it feels dry, 'rings out' sufficiently while bouncing
an end off the cement floor, or reads dry with my moisture meter, I don't shellac them and they're just fine... again though, maybe it's the relatively stable environment. Not sure why, but cracks while heat correcting, reflexing, or recurving hasnt been a problem for me.
This in my first dry stave to crack with well over 1,000 osage bows under my belt now. I don't plan to change anything if only one in a thousand develops a micro crack. I am going with the theory that I just thought it was dry and it wasn't.
I have never found any need in sealing the back on a dried stave either. Green staves I don't take a chance on and rub the back down with whiteglue.
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I had some 20 year old Osage do some very odd things while heat-treating it several years ago. The belly started roll and bubble as if it was full of water leaving cracks that ran deep into the wood, ruined the bow. I've been very cautious with Osage since then
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I had some 20 year old Osage do some very odd things while heat-treating it several years ago. The belly started roll and bubble as if it was full of water leaving cracks that ran deep into the wood, ruined the bow. I've been very cautious with Osage since then
I had the same thing happen on the Osage bow that I'm currently working on. I don't think mine is ruined though. This stave even buckled on the trimmed sides when I heated it. It had been cut four years ago and been stored inside the house for the last two years.
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I use my moisture meter all the time. I keep checking right until I string it up for the first time.
Sometimes I still get surprised.
Jawge
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I have had wet ones crack on me when recurving or heat treating. Never a dry one. Also I have never once sealed the back of any stave fresh cut or not. Just the end grain.
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When I used to dry heat osage I sometimes got cracks, especially with really old osage. After I started to use vegetable oil with dry heat I haven't encountered the problem again.
I also used to use shellac on the back whilst seasoning, but I found that the shellac seemed to seal in the dry heat/moisture so much that it had to explode from the build up of pressure internally in the cells. No cracking on the belly side that gets the heat but many tiny fissures on the back, hard to see unless you get up close.
So now before I use dry heat, I either scrape off any shellac, and coat the bow in oil, no problems anymore.
Hamish
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I think in this discussion, we need to clarify whether we're referencing heat TREATING the belly, or heating to change shape, as I think there's a big difference in the two techniques and how each of them can affect the wood.
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I have had that happen from time to time, Like marc I am very careful with Osage now. My rule if it is less than 2 years old I steam first and then heat if needed, older than 2 I just heat. I always seal the back and use cooking oil while heating. I had a run of that a couple of years ago ,probably as Pearl said moisture, it was a wet year but I figured it wasn't that much trouble to seal and oil so I do that all the time now. No problem as of late. Usually the cracks caused no problem, ha that's what snakes were made for, hide the flaws. ;) ;D ;D
Pappy
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Like most of us, I experience the same cracks from time to time. Our humidity is a bit higher here in Michigan though. I fill with super glue and continue on with the bow. I too steam 2 year or under wood; usually backed up with a heat gun to keep it hot during my tweeking. Dry heat on older wood.
I would be weary about leaving the bow in a hot car. I've seen some osage return (to some degree) back towards its "original" state when exposed to excessive heat after corrections were made.
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Matt, I plan to do a lot more steam work with osage than I have in the past. I have gotten more than my fair share of cracked limbs when recurving, my own fault I know but I have a better success ratio with steam on recurves.
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Steam everytime for me with recurves too.
Badger - california...50% rh....8% emc....sunshine....over a 1000 osage bows! Well I'm jealous even if nobody else is!
Newcastle....70 - 90% rh....13% emc....rain/cold....about 10 osage bows..... ;) ;)
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Steam everytime for me with recurves too.
Badger - california...50% rh....8% emc....sunshine....over a 1000 osage bows! Well I'm jealous even if nobody else is!
Newcastle....70 - 90% rh....13% emc....rain/cold....about 10 osage bows..... ;) ;)
Mike, I was exagerating, probably 1/2 that many osage bows would be more accurate.
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I'm no where close to a 100 bows like BADGER but I have biult over 100.
But I've cut and sold a 1000 other staves.
I also after ruffing out my bows. I've never resealed any and it's been a year for a couple before they got finished. As long as their in a dry place there good.
I quit useing heat on moveing parts long ago. I do bend handles and tips if I need to. I've mever seen any cracks doing this.
But for lots of bows. I ruff them out green and but them on caul. To get the tips,handle inline. To be finished when I need it.
Alot of the others I'll ratchet strap them down beteen saw horses while green to add reflex.
I also have a lot just straight staves. Give me a PM if anyone needs a stave.
Only reason I can thing of is your stave had a small amount of moister. Or it could be relitive hummity exspecially if you live where theres high hummity. But I've never seen this and there was a time when I heated quite a few osage.
Thats why there small cracks because theres only a small amount of surface moisture.
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Just had a 5 year old light yellow stave send out many longitudinal cracks while heating to bend. Its dry for sure but cracked under slow heat. Not life threatening but annoying for sure. Heat was on belly, cracks, belly to back.