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Moisture Meters

Posted: Tue Apr 20, 2010 11:17 pm
by riot_nrrd
Hey everyone - I am looking at purchasing a moisture meter. Fine Woodworking seems to like the Ligno-scanner SD, but I'm not sure I want to spend that much money. What do you use, and how do you like it?

Posted: Wed Apr 21, 2010 10:59 am
by pennview
I have two -- an Electro Physics pinless meter and a Mini Ligno pin type. The latter I obtained just recently at an auction for a few dollars. I've had the Electro-Physics model for about 12 years and prefer it over the Ligno.

New, I believe the ElectroPhysics was about $200 and the Mini Ligno about $100.

Between the two, I prefer the ElectroPhysics because I believe it's more accurate. It has a dial for selecting the density or specific gravity of the wood being tested over a range of .4 to .8. Whereas the Ligno lumps the woods into just two categories, treating a light wood like Basswood (.37) the same as a dense wood like Shagbark Hickory (.72).

I use a meter to determine if the wood is suitable for a building project--that is the moisture is about 8 - 10 percent. I mostly buy wood these days at an auction or green, with most of it being air dried and so you never know exactly how dry it is. With a meter, you can keep track of the drying progress and don't have to guess. My wood is stored in a variety of places -- outside, the garage, shop, and basement, so the moisture content varies quite a bit. I've had some bad experiences with kiln-dried wood cracking after assembling a project, so I've come to the conclusion it's better to be safe than sorry.

I just went to the basement and used both meters to test some walnut I bought last month. It had been either air dried or dried in a solar kiln, but subsequently stored in a shed. The Electro-Physics meter measured 11 percent, the Ligno 14 percent, so both meters tell me it's not ready yet.

Posted: Wed Apr 21, 2010 8:53 pm
by boostfan
I didn't start the thread, but I loved the great information. I have several Walnut logs from a couple trees I had cut down last fall. After reviewing several options, I ordered a Granberg chain saw mill today, so I will be in the market for a meter soon.

Posted: Wed Apr 21, 2010 10:00 pm
by charlese
riot_nrrd wrote:Hey everyone - I am looking at purchasing a moisture meter. Fine Woodworking seems to like the Ligno-scanner SD, but I'm not sure I want to spend that much money. What do you use, and how do you like it?

Hey there, Riot! You have asked a question that hits on one of my most favorite subjects. Rather than go on - I'll throw you(s) a thread and a couple of posts from back in 2008 that discuss Moisture Meters. If there are more questions I'll be glad to blab on:rolleyes: .
https://forum.shopsmith.com/viewtopic.php?t=2176&highlight=moisture+meter

Here's the posts:
https://forum.shopsmith.com/viewtopic.php?p=12796&postcount=6

https://forum.shopsmith.com/viewtopic.php?p=12905&postcount=8

A reliable MM should come with conversion tables for different species of wood. The one I have is designed to measure moisture in Douglas fir. Conversions are necessary for different species because of their various densities (specific gravities). Even a single board of red oak (most of my experience) will show differing results on the meter because of differing densities within the board. It is up to the user to determine if the meter readings are caused by moisture or by density.

Posted: Wed Apr 21, 2010 11:13 pm
by riot_nrrd
Thanks Chuck - good info. I'm starting to get the feeling that if I want a good meter, I'm going to end up dropping a couple bills on it. The Ligno-scanner, the Electrophysics, and the Wagner all look great. I guess I just need to suck it up and remember that you get what you pay for. :-)

Posted: Thu Apr 22, 2010 10:13 am
by pennview
Originally Posted by: charlese

Hey there, Riot! You have asked a question that hits on one of my most favorite subjects. Rather than go on - I'll throw you(s) a thread and a couple of posts from back in 2008 that discuss Moisture Meters. If there are more questions I'll be glad to blab on .
http://www.shopsmith.net/forums/show...moisture+meter

Here's the posts:
http://www.shopsmith.net/forums/show...96&postcount=6

http://www.shopsmith.net/forums/show...05&postcount=8

A reliable MM should come with conversion tables for different species of wood. The one I have is designed to measure moisture in Douglas fir. Conversions are necessary for different species because of their various densities (specific gravities). Even a single board of red oak (most of my experience) will show differing results on the meter because of differing densities within the board. It is up to the user to determine if the meter readings are caused by moisture or by density.
Good points and good reading, Chuck.

I'd add a couple of things though. The Mini Ligno I have doesn't come with a Conversion Factor for the various species, it simply has two settings and a list of woods that fall into each category, but one could work out those densities if need be. Therefore, it would be good to see what the instruction manual looks like before buying a moisture meter. I can't complain though as I only paid $8.00 for it at an auction.

As you point out, density can vary over a single board and therefore you get different "moisture" readings depending on where you put the meter. The way I deal with this, in using my Electrophysics pinless meter, I plop it down on the board, take a reading, and write the moisture content on that spot with some chalk. So the next time, I know the previous reading and where it came from.