Primitive Archer
Main Discussion Area => Bows => Topic started by: Greebe on January 04, 2015, 03:39:57 pm
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Hey guys and gals,
I was looking around for a chart to tell me the moisture content of wood when making bows. I found this one that can be downloaded as a pdf and printed. It tells you the moisture content of wood based on the air temp and humidity.
https://www.finewoodworking.com/FWNPDFfree/equilibrium-moisture-content-chart.pdf
Hope that helps someone.
Greebe
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Just use a kitchen scale to see moisture content. Here in the wet PNW wet wood is no joke
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How would a kitchen scale give you the moisture content?
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because moisture content is physical weight that can be measured.
If I had 2 staves sitting in the corner, one cut a year ago one cut last week,
would the chart tell me it's the same moisture content in each stave?
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Cut a scrap piece of the wood you are going to be working on.
Weigh it accurately.
Dry it completely in an oven till it loses no more weight.
A bit of maths and the two readings will give you a definite m.c. reading.
Just weighing them will only tell you if it's still losing weight. (still heading for E.M.C.)
If it's losing weight it's due to it trying to get to E.M.C. which is what the chart tells you.
The chart DOES NOT tell you what moisture content the wood is....it tells you what it's heading for IF nothing changes with the temp and the relative humidity.
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This chart is a great help. Been using it for years. It wont tell you the exact MC of a full stave nessisarily but that's not really that important to me. But used in conjunction with a kitchen scale it will tell you MC pretty accurately.
Take a roughly floor tillered bow blank that's been sitting outside and has lots of moisture. Weigh it and take it inside for the next few weeks. Weigh it again every few days. When it stops loosing weigh for 1/3 of the time it's been drying it has equalized to its environment.
Now assuming it's been in a stable environment your chart will tell you approximately what the MC in your bow blank is. Not where its heading or where it's been even just where it is.