Primitive Archer
Main Discussion Area => Bows => Topic started by: DC on June 14, 2017, 11:17:25 am
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I've been working on an OS recurve. When I finished working on it last night I weighed it(542grams) and then put it in my warm box(50%RH). This morning it weighed 540 grams. Does a 2 gram weight loss overnight call for some attention? Is it enough to maybe leave it in the box for a few days? Having been raised with the standard system two grams by itself doesn't mean a lot to me. I know that 2 grams is 2 cubic centimetres and that looks like quite a bit of water to come out of a "dry" piece of wood. The wood was as dry as I normally use but it's been exposed to our usual 70% RH for about a week.
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thats 15 grains,, I dont have an answer for you,,
if I knew what the moisture content of the wood was,, I would be more opinionated,,
but I have a feeling some of the guys gonna tell you to let it dry a bit,, I never did use a heat box with osage much,, so its out of my area of expertise, ::)
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That reminds me of someone checking their heart rate and blood pressure too often. That is a normal fluxuation. Your bow has to live where you live. I would build it at ambient RH unless it has been exposed to some unusually high moisture conditions.
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If you lived in a dry place, more types of woods could prove to be useful? Isn't the RH along that part of the coast very high year round? that might be a practical limitation, as some woods are known to pick up moisture faster than others. Have you tried to compare the weight gain/loss rate of different species by keeping some similar samples both in and out of the box?
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The RH is 60-70 sometimes 100%. I found a corner of the house to store my bows that is around 50% so I'm pretty good there. The RH here puts the wood's MC at about 12-14% which, I've been told, leads to lack lustre performance. It's the set it can cause that irritates me. I never know if it's me or the RH that cause it. I'm going to track the weight of this bow to see if there's a pattern. I also have a few equalised staves that I can experiment with.
Thanks
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Above 10% you will start showing more set. I am like you it irritates me. We average about 64% where I am at on the ca coast. I find some woods tolerate it better than others. I really like hickory but not where I am living. I can't get the performance out of them at 10% rh or more.
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I did a little thinking. If the bow weighed 500 grams and was equalised at 50%RH the MC would be about 9% which is 45 grams of water. If it was 70%RH it would be about 13% MC or 65 grams of water. The 2 grams I noticed is not even going to raise it to 10% so I'm OK.
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... Isn't that what you were expecting? You put it in a "warm" box with somewhat low humidity; of course it's going to dry the wood out and it's going to lose water weight.
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It was the amount I was wondering about.
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Only 30 grains of weight gain is'nt much of a percentage gain.That's what's in 2 grams I think.I keep 2 dehumidifiers running in the basement at my place to keep it at 50% humidity.Upstairs is air conditioned too.Analog humidity gauges setting around.Reason why I don't use a hot box.
I've read Tim Bakers' findings saying each 1% moisture gain is 6% performance loss or something like that.So 3% moisture gain is 18% loss then.It does add up.
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Normal fluctuation....don't stress!
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What the others have said! The crazy thing is it has also an effect on the draw weight - check it out!