How many of ya trust your moisture meter????

[Bill White]

Have a Delmhorst meter. New batts, etc.
Just wonderin' how do ya cross-check the readings???
Wood is old, and has been stored dry for quite some time.
Is 8% (which I think is good) an accurate reading?
Bill

[Rob Holcomb]

I don't know where you live but 8% is exceptional for air drying. Most locations it's difficult to get that low of a moisture content because your lumber will acclimate over time to whatever the humidity level is in your shop. Only the driest of regions will achieve 8% from air drying. The best I have seen here in Western NY is 11% in my shop. As far as moisture meters go, I have a Delmhorst meter too. When I bought it, I had just recently gotten several boards of Cherry that myself and a friend had cut from a log he had on his property that came from a tree he had taken down two weeks prior. I wanted to get an initial moisture reading and expected it to be 25% or higher. Much to my surprise, the reading was 14% in several places on the boards. So I bought new batteries and re-calibrated it. Same result. 4/4 Lumber that's been air drying for more than a year in my shop shows a reading of 11% so I know the reading was nowhere near accurate. I don't put much faith in moisture meters anymore. I would rather go with either kiln dried lumber or if air drying, stick to the one year drying time for each inch of thickness.

[larry senen]

you would have to have two or more meters. different types as well, pin and pin less.i have a friend that installs floors, and thats what he uses

[Rick Moyer]

you would have to have two or more meters. different types as well, pin and pin less.i have a friend that installs floors, and thats what he uses
I don't understand what your friend uses from your comments??
I also don't have a moisture meter, so I am curious what others use and are confident with. Been thinking about getting one but not sure what.

[Bob Vavricka]

Why not check your meter by using the oven dry method. That should tell you if it is accurate enough to trust your measurments. A post in this thread explains the oven dry method. http://www.sawmillcreek.org/showthread.php?173476-What-moisture-meter-to-get&p=1787632#post1787632

[Lee Schierer]

I have a Mini Ligno Tech meter that is several years old. I trust it. When I bring home wood from my local sawmill that kiln dries, the MC is about 7%. After a period of time in my shop which is part of the house, the MC adjusts to 8%.

To check your meter go to your local lumber mill (not one of the Borgs) and ask them to check yours against theirs. Most likely they will agree to help you if you are a customer.

[John Piwaron]

If you own one for any length of time, you'll get a sense of whether or not it's trustworthy. Just observe the wood. That's kind of "seat of the pants" but it seems like a workable solution.

For example, my bench is hard maple. My meter says 14, with the correction that's 11%MC the bench has been in my basement shop for years. A hard maple board I just brought home from the lumber store was 7% on the meter. 5% with correction. I don't know that kilns can or will get it that dry, but it's clear that what I bought has come out of the kiln recently. I have to let it acclimate to my shop. If I don't, it'll move. Every time. If I do, it stay's where I plane it.

That store bought board is at 7% (corrected) now. It might be another week or two before it matches the bench.

In other words, my bench is my reference. Is that the right thing to do? I don't know.

[John Coloccia]

http://www.csgnetwork.com/emctablecalc.html

Look at the EMC chart. That's where'd you'd expect it to be.

Yes, I trust my Delmhorst. It's the only one I trust, actually.

[Rod Sheridan]

http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr06.pdf

I don't have a moisture meter, I use a megohmeter to measure the wood resistance, converting to moisture content using the chart in the attached link.

If you want to check calibration go to an electronics store and purchase a handful of 10 megohm resistors, they should be very inexpensive.

Connect one resistor to your meter, I've decided to use Black Ash as the wood I'm measuring.

From the chart for that wood, 10 megohms should be 14% (you may need to use the correction chart for species that comes with your meter)

Now connect 2 10 megohm resistors in series (end to end) which results in 20 megohms, your meter should now indicate 13% from chart

4 resistors in series, 40 megohms = 12%

8 in series or 9 in series should indicate 11%

Regards, Rod.

[Cody Colston]

I have two, both inexpensive meters, the General from Home Depot and a Mini-Ligno ED. They consistently read within 1% of each other so I think they are both reasonably accurate...at least between 6% and 20% MC. If I was selling lumber I would definitely have a more reliably accurate meter and would expect to pay over $200 for one.

The thing is, mine are both pin-type meters and only measure the MC of the wood as deeply as the pins penetrate. You have to be certain you are measuring the MC "in" the wood instead of "on" the wood. It's not at all unusual to measure 8% MC on the outside of air-dried wood. However, the MC at the core is often quite a bit higher. To measure inside the wood, you need hammer probes (Delmhorst makes them) a pinless meter or you can cut a piece of wood at least 1 ft. from the end, rip it in two and check the MC on the newly exposed long grain.

[Chris Fournier]

That's a high quality meter and I would expect that it is very accurate as long as you check the tables for temperature and species adjustments. I have air dried 10s of thousands of BFT of lumber and in Ontario Canada I can get it down to 4 percent if that is my goal. Drying lumber is a pretty simple process and as long as you understand what's going on you can achieve usable lumber by air drying with proper technique and patience.

[John TenEyck]

I also have a Mini Ligno and it is accurate within 1% when measuring small blocks of wood and then checking them with the oven dry method. As Cody said, the inside of a piece of wood that has not been in your shop a long time may be higher, or lower, than the outside. I'm in WNY, too, and wood in my shop is now about 6% since the humidity is 30% and has been for over a month. For wood that's been in my shop (which changes relative humidity slowly and only from 30 to about 50% from Winter to Summer) for several months, referencing the EMC vs. % RH chart in Hoadley's book tells me the MC. For wood I buy I use, and trust, the Mini Ligno.

John