Author Topic: Moisture content  (Read 1547 times)

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Offline DC

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Moisture content
« on: December 07, 2019, 10:05:22 am »
I think we're all familiar with the MC chart http://www.csgnetwork.com/emctablecalc.html
I got wondering the other day if it could be used it reverse. I grabbed a dry billet off the shelf and put it in a plastic tube, put in a hygrometer and sealed it all up. We're just getting over a cold snap so any heated area of the house is down around 15-20% RH. The shop is heated half the time so the RH is a bit higher. The billet is only about 1" thick. The hygrometer had been in the house so it was reading 15% when I put it in the bag. An hour later I noticed that the RH in the bag was 20%. This morning it was 37%. Looking at the MC chart, that would put the billets MC at about 7.5%. I'm assuming that this will be a slowish process and that the RH in the bag will increase as the moisture moves out of the wood.
Do you think my logic holds here or am I missing something? So far it's making me think that my stash may be a lot drier than I think.

Offline Pat B

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Re: Moisture content
« Reply #1 on: December 07, 2019, 10:50:08 am »
DC, it might take a while for the M/C of the wood to stabilize. Wood absorbs moisture at about 1" per year so using that formula it should take about 1/2 year for the wood to rehydrate to the M/C you desire.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline Selfbowman

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Re: Moisture content
« Reply #2 on: December 08, 2019, 09:24:28 am »
What would be the desired mc for Osage by you guys? I have heard everything from 7-10.
Arvin
Well I'll say!!  Osage is king!!

Offline DC

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Re: Moisture content
« Reply #3 on: December 08, 2019, 09:36:03 am »
DC, it might take a while for the M/C of the wood to stabilize. Wood absorbs moisture at about 1" per year so using that formula it should take about 1/2 year for the wood to rehydrate to the M/C you desire.
You're right. It seems to have stabilised at 38%. That would fit with the way the RH has been going. That will just be the surface of the billet though. If there is excess moisture in there I should at least see a slow rise. Kinda like weighing staves. I'll watch it for a while. At least until I need the hygrometer for something else :D

Offline bradsmith2010

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Re: Moisture content
« Reply #4 on: December 08, 2019, 09:52:49 am »
I put rawhide on a bow and strung it too soon,..it lost couple pounds,,,then later when dry it regained to normal...