# Moisture meter use with resinous woods



## Gary Beasley (Jan 21, 2009)

Don't know if this is the right forum but I have a question about measuring moisture in rosewood and other resinous or dense woods.
I have one of the meters with the contact pads if that make a difference. The rosewood I have seems dry but the meter says 28 percent, the mesquite wood I have run through the microwave warming cycle three times at an hour apiece and still measures in the 20 to 25 percent range. Do these types of wood read differently from say oak or maple with most meters?


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## jeffreythree (Jan 9, 2008)

I believe it is a density issue, not resin. The higher end meters can be calibrated for the type of wood being tested, I believe. Others I have seen come with a chart showing error for different species than the one it was calibrated to. Hopefully someone will chime in who owns one, not borrows one.


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## TexasTimbers (Oct 17, 2006)

If your meter has a chart like Jeff mentioned maybe it'll list the particular species for the correction. Mine does but best I remember none of the species required more than 1 or 2% correction. 

I can't answer your question specifically because I never thought about it really. I guess I just trusted that if resin had the ability to dramatically skew readings, the meter company would have included the information on that. 

But regarding your mesquite drying in the radar range, don't know what sizes we're talking here but for small bowl blanks for example you'll have better success if you'll soak the blocks in a high grade alcohol for a day or two, take them out and let them sit for a few hours (not in wind or sun just in the shop somewhere), then hit them at full power (one at a time) for ~30 minutes depending on the size. After you've cracked a few you'll get the hang of how long you can zap them. Then let them sit to relieve stress for an hour or two then back in the alcohol bath. 

Not as much work as it sounds if you only have a few, but letting them dry naturally is much less fuss if you can wait, and you won't ruin any during the learning curve.


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## Gary Beasley (Jan 21, 2009)

This thing didn't come with a chart. The mesquite is cut into 5/8" pen blanks, I was trying to get them done enough to turn without later shrinkage and cracking. The microwave usually dries pen blanks pretty fast on the warming setting. Any higher and I can get burn marks inside the wood.
I was hoping I could get some rosewood pen blanks good and dry too but the moisture meter is not telling me a good story.


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## ketthelps (Jul 31, 2010)

*Moisture and wood species*

Dear Gary:

Jeffrey is right, on "electrical type" moisture meters, there is a compensation that needs to be made based on the wood species and is generally done by density (specific gravity).

However, each meter will have a different adjustment based on both the wood type and the moisture it measures. If you don't have that in place, what you can do is measure the wood, dry it, measure again until it goes down to a "stable" value. Unfortunately, this may take you to a "bone dry" condition where the wood becomes drier than you'd like.

Remember to allow the wood to cool to room temperature as the temperature of the wood will also change the moisture values.

Higher end meters will provide automatic temperature compensation and density adjustments


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## Gary Beasley (Jan 21, 2009)

Thanks for the input everybody. I'll see if theres anything I can find about the meter online but theres faint hope there.


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## ketthelps (Jul 31, 2010)

Gary:
Have you contacted the manufacturer of your moisture meter? Ours include the correction sheet (older instruments) and the new ones automatically correct to display the proper moisture content.


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## Gary Beasley (Jan 21, 2009)

It's a Ryobi meter. They have very little on the web site for info on the unit. I've got a feeling they don't consider it high end enough to require corrections.


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