Primitive Archer
Main Discussion Area => Bows => Topic started by: Jesse on February 10, 2009, 01:11:12 am
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Just wondering if you guys have ever had bows gain a lot off weight?. I asked Robsbass how the maple bow I made was holding up and apparently it gained 8# and is now 62#. When I shipped it the weight was 54#. Its gotta be moisture but the bow was really really dry when I sent it ???
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if his climate is dryer
i could see that happening
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Yea, I've had that happen a number of times. I haven't quite figured out why though.
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I have seen Hickory do that a lot.Put it up in a dry place for a while and it will pick up weight.
It has to be MC that dose it.
Pappy
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Its the cold dry air I bet Jesse, I've noticed tha my bows have gained weight in the low humidity of winter.
Ya have to be careful that it don't get to dry and blows up on ya :o
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Jesse, I made my brother-in-law a osage bow several years ago and he couldn't put down his compound long enough to use it. Stored it in of all places his attic! He gave it back to me and when I found out where he'd been storing it, I put it in my basement to hopefully pick up a little moisture. I haven't strung it yet...
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Nope. It's always the other way around here. Jawge
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Yea must be too dry.
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I had an ash bow pick up about ten pounds over a few years. It was still a bit moist and unseasoned when I first made it.
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Is he in Georgia? I have friends back home in Georgia and their deer and turkeys seem to gain alot of weight over the weeks and years... ;D
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All of mine gain a few pounds during the winter... I do too ;D
It's because the relative humidity is lower and the moisture content of the wood drops. ;)
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99% of my bows I make in the Winter which is very dry here. Then when Summer arrives the humidity soars so I have to keep my bows in the AC which removes the moisture or they take set and the loose weight. Jawge
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This may be a classic case of demonstrating the difference between dried and "cured" wood. Despite what Tim Baker would have us believe, there is a difference.
No question that wood can safely be dried and used quickly but that little extra bit of time does something to wood that mere drying won't.
You can kiln dry an axe handle and after a couple of years the wood will still shrink and presumably become slightly denser. That's what happens with bows picking up pounds down the road.
You should be able to feel the difference in wood that you have quickly dried and the stave that you forgot in the corner for 5 years as you work it.
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This stave was cut in late summer of 2007, split immediately and air dried in rack protected from the weather, sent it Jesse last Dec or so
and he had it in his basement.
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I agree with PatM. There is a difference between dry and cured wood. Art Butner brought this to my attention in reference to hardwood shoot arrows but it is also appropriate to bow wood. The longer wood cures the more stable it will be. As the resins, etc cure out(solidify), they are less affected by moisture because they become less water soluble. This does not eliminate the hygroscopic action of the wood but will lessen the effects somewhat.
Wood is hygroscopic....meaning it takes on and releases moisture as the R/H rises and falls. The slower we can make the hygroscopic rate the more stable the wood will be. We can not eliminate this and don't want to eliminate it. Just like us, the wood needs to breath and M/C is a result. The amount and rate of the M/C is what we are trying to control.
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One thing about this bow is it was only a matter of a few weeks from when Jesse finished it and sent it to Rob,
so I don't think the wood cured in that short of a time. Not to say there isn't a difference between dried and cured.
Just in this instance I believe it was low humidity that caused the weight gain.
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I think it could be a difference in our scales also. I had that stave in the hot box for two moths straight and it was already at 10% when it went in the hot box. I dont think it could have gotten that much drier. Not 8# in a few weeks .but ya never know :)