Opinions on moisture meters

[Doug]

I'm in the market for a moisture meter and want to know if there are any brands or features that I should look for or avoid.

Thanks, Doug Chapis

[Edwin Pawlowski]

I have no idea what they should be like, but Woodcraft does happen to have one on sale. I got the email flyer yesterday. Ed

[RB]

I don't have one so can't offer an opinion.

I would like to know though what you will do differently after you buy a moisture meter. I'm trying to understand why I should consider one. I certainly won't play golf tomorrow just because the moisture content in my wood is too high, or too low.

RB

Doug wrote:

[Wilson]

[Jon Endres, PE]

I have a Lignomat, one with pins. If you want a pinless, (i.e. doesn't leave small holes in the wood), Wagner makes good ones. There are many reviews over the past few years in different magazines and online, do a few searches. I am happy with the one I have. It seems like it would be more accurate in a thicker piece of wood than a pinless meter.

Jon E

[George]

I don't either, but used 'em at the university. It's a bit like using a micrometer on a tablesaw that's producing good cuts to see how far off it is. Precise, but with little meaning if your wood's the same MC. Stored properly it should be, and then the rules of good joinery take over. Build tight in wet, loose in dry to take care of the future.

If you get wood from disparate places and are in a rush to complete, I suppose you might make allowances in construction based on the meter readings rather than the relative humidity.

[Tom Watson]

I have an older Lignomat with a pin style probe that is good for thicker stock.

I also have a Wagner pinless which reads fine on surfaced material up to about 5/4 thk.

I use these in conjunction with a digital sling psychrometer that lets me take humidity readings of the area that a piece is going to live in.

Since my shop is in a valley and next to a stream, my wood pile tends to run a little higher than the norm, as far as moisture content goes.

Using the information from these tools, I can condition the wood before working it, to get it to the proper equilibrium moisture content for the space that the piece is going to be in when completed.

Whether the sticks come from my racks, or are purchased from the supplier for a specific project; each piece is checked for moisture content. A stick that reads too wet can then be set aside, in favor of one that is within the correct range.

Regards, Tom.

Thomas J.Watson - Cabinetmaker (ret.) tjwatson1ATcomcastDOTnet (real email)

[Andy Dingley]

Save your money.

I've only got a fairly cheap one, as I can't afford the _serious_ money for a good one. I rarely use it anyway.

What I have instead are half-a-dozen cheap air hygrometers (and a couple of better ones). I measure the humidity in my workshop, in my house (as a destination for furniture) and in my various timber racks. For timber that I've had long enough to equilibriate, my estimated EMC values from the air measurement and the ubiquitous graph are in very good agreement with any MC measurements I've done with borrowed good quality moisture meters.

I find that thinking seriously about moisture content and beginning to understand it has been a great boon to me. But when it comes to measuring it, I'm better sticking with the air.

Of course, if you're buying timber from someone else's stacks, then YMMV.

[Mike G]

Drying wood requires time, money, and a tied up investment.

Hard though it may be to believe it is not absolutely unheard of for someone to cut a corner or two and sell wood for furniture construction that may not quite have an appropriate moisture content for that use.

Yes, I know how absolutely unbelievable it is that kind of thing could happen but trust me, not everyone is Mr. Nice guy.in the real world.

A moisture meter is a good way to check to see if you are dealing with someone who is selling the real goods and it doesn't hurt to occasionally spot check your local suppliers once you have found a reliable one..

Note, if you should find wood with too high a moisture content it is not necessarily the local suppliers fault. Maybe they don't have a moisture meter either.

[JMWEBER987]

I just purchased 230 board feet of red oak that the seller had gotten a reading of 12% MC on. A friend who also purchased the same wood from the same stack used his meter and it read 20%. There are some good tutorials online about drying wood and I happed across one that gave directions on how to REALLY find the MC of wood. You need an accurate scale, and over than will maintain about

220 degrees F and an appropriatly sized piece of the wood. The process is to first weigh the wood and then place it into the over at 220 or so. Take it out every 24 hours until the weight so longer changes between 24 hour periods. Subtract the ending weight from the starting weight and divide the difference by the ending weight. That is your MC. I just finished doing this for the red oak I purchased and it calculated to 14.3%. My wood started at 862,8 grams and ended 12 days later at 754.8 grams. The weight drops quickly at first and then slows considerably as the free water is quickly evaporated. The vapor inside the wood cells takes longer to migrate to the surface. If I find the URL I'll post it. Mike in Arkansas

[Mark L.]

[Frank McVey]

Hi, Mike.

The oven method is certainly the most accurate method of determining MC. It isn't necessary to use the whole lump of wood - a centre-board offcut from the centre of the stack is best (although not always convenient) - a representative sample, in other words. Don't use an end off-cut, since that is always drier than the centre of the board.

I was drying some air-dried oak wedges last week (snippet for newbies - use bone dry wedges in your projects - they'll take up moisture afterwards, and never go slack), so, for the first time, I used the microwave oven on defrost setting ( having read about microwaving bowls on rec.crafts.woodturning) and it works extremely well. As you say, just keep weighing the piece until it cease to lose weight. Difference was, it took around 4 hrs, as opposed to days, measuring the weight every hour or so. According to calcs, it went from around 18% MC to zero.

There was no apparent distortion in the samples (other than the shrinkage you'd expect, but they were pretty straight-grained anyway), but there was a significant raising of the grain, quite a bit more than simply raising the grain with water before finishing.

A note for the newbies reading this - under most circumstances, you don't want 0% MC in your stock - you want the MC of your furniture etc, to be at the same level as that of their surroundings. A bone dry board taking up moisture can be just as apt to warp as a wet board losing it. Sticking your MC meter into a door jamb or a skirting board is quite a good way of establishing the current MC of a room.

Cheers,

Frank

[JMWEBER987]

Along these lines I am letting the board sit inside until it stops gaining weight (mositure) and well see where it stops. Then going to place it outside and see what it does in the Arkansas summer humidity and again this winter. The gain so far has been small and very slow. Mike in Arkansas

[Doug]

Thanks for all the good information. I had some lumber cut up last weekend and want to keep track of how well its drying out.

[George]

the air drying and storage publications. Might save you money, as the wood is still fresh.

Oh yes, they also have a publication on moisture meters, as long as you have one.

[nospambob]

[Mike G]

Well, that too but those suppliers that consistently supply green stock you don't go back too.