Moisture Meters

[Craig Bumgarner]

Any preferences? I've been using a Tramex which uses surface pads, not probes. My vague understanding is it uses a radio wave to measure the dialectic of the wood. Higher moisture, higher dialectic. My understanding is it measures about 1" deep, but I don't have empirical confirmation of that. It seems okay, but I really have nothing to compare it to.

[Brad Heinzen]

Most of those meters come with documentation that tells you how deep they measure. Mine is apparently designed to read correctly only if the material is 3/4" thick. It's also based on an average species density which I have to choose from a chart. Although I do use my meters (I have a pound-in probe type as well) for general carpentry, I haven't really found them to be very useful for luthiery. If I've got materials that I know I'm going to track, I weigh them in, and re-weigh occasionally to see if they've reached equilibrium.

[Craig Bumgarner]

Brad,

I agree, I have been going more by feel than anything, but I thought I should probably get more quantitative. The moisture readings I get don't give me much more. I like the weighing idea, never thought of it, but that makes a whole lot of sense. Thanks.

[Steve Senseney]

I have an old moisture meter (with pins), but don't use it.

You can get some information by checking other boards in the same storage area as your luthier woods. In other words, have some cheap framing lumber that you can check periodically to see if your storage area is gaining or losing moisture in all of your wood.

[Bob Gramann]

I bought a cheap (expensive for me but cheap in the range of prices for those things) moisture meter. It was a pin type meter and read out in per cent moisture content. It has no correction for wood type. I found it to be next to useless. It would read 24% if the wood was obviously wet and 8 % the next day when the wood was no longer cool to the touch. I've been using the weight method described by Brad for many years. It's reliable. I imagine a very expensive meter might be more useful than what I bought but I still wouldn't trust it until the weight of my piece stabilized.

[Craig Bumgarner]

Okay, I like the weight idea. Just cut some neck blanks from 12/4 stock. Feels fairly dry. One blank weighs 500 grams. What kind of change over time can I expect if it is drying out? Or stable? Is it an oversimplification to say a change of 5 grams is 1% change in moisture content? It will be a couple months before I want to use them, so I'll find out eventually anyway, but just wondering.

Is an air conditioned room at 70 better for drying than an un-conditioned shed that routinely gets to 100 degrees in the daytime and 80 at night, this time of year, in Maryland, generally high humidity? I'm guessing they are probably about the same, with the low humidity but low temp, offsetting high humidity and high temp. At least the AC at 70 degrees is constant.

[Bob Gramann]

I build in a room where I keep the humidity around 40-42%. When I brought some Osage Orange in that had lain in a field for 30 years before it was cut, it took about a year for the weight to stabilize in the pieces I first used. I put some fresh cut walnut in my outdoor shed (in Virginia--probably similar conditions to yours) three years before I brought it onto my room. I cut it into back and side sets. The weight on those stabilized in a few weeks. Some kiln-dried persimmon stabilized in a few weeks. I like for it to go more than a month without the weight changing before I feel secure that it has acclimated to my shop humidity. The thinner the wood, the quicker it gets there. I've used all of the boards that I weighed and wrote the weights on, so I have nothing but memory now--I can't give you actual numbers.

[ThomD]

I have a pin type measurer, that in it's day was well regarded. I rarely use it. Wood will dry to ambient, if you just leave it, and I rarely get onto my wood at a speed where it becomes an issue. Ambient is basically what I have to work with, so I don't sweat it beyond that. I have a hot box for process control, but eventually the guitar is going to ambient.

Recently I cut a lot of beech, and it turned out that it dries really fast for the size of the stock. Something to do with the pores and rays. It seemed dry, but I could hardly believe that 3 inch stock was dry in a little over a year. I got out the moisture meter to confirm things. That is about the only use it gets.