Wagner Extended Range Moisture Meter (MMC220)

We've all heard the old adage, "good things come in small packages". Well I'm here to tell you that the principle can be extended to include the Wagner Electronics MMC220 extended range moisture meter. This thing is hard not to like. Right out of the box it screams quality, from the heavy-duty nylon carrying case with its spring loaded belt clip, to the no-nonsense tool itself.

This is a tool that I really wish I had years ago when I was gathering a stash of musical instrument tone woods (mostly North American spruce, mahogany, maple, East Indian rosewood and ebony). Back then, I occasionally had access to a finicky moisture meter that required the stabbing of two prongs into the wood to obtain a reading. It was cumbersome and I was never positive that I was getting accurate readings since they varied considerably over small areas of the same stock. Moreover, the wood dealers were not too keen on having me poke the device's prongs into their wood, especially when the wood had been thicknessed to 1/8" or less. As I recall, it was also prohibitively expensive.

The MMC220 has none of those problems. Its operation is simplicity itself with an On/Hold button and a Species button to select the Specific Gravity of the species of wood being tested. To take a reading, say of teak, you would look up the Specific Gravity of teak (SG=0.59) in the accompanying pocket-sized booklet, and then enter the figure into the meter by means of the Species button, which can be advanced in increments of ten or one depending on whether the button is held down or pressed iteratively. The Specific Gravities booklet lists the data for a wide variety of hardwoods, softwoods and exotics, plus plywood and OSB (oriented strand board); many others can be found on the Internet. To obtain a moisture content reading, the meter is simply held flat to the surface of the wood being tested and in a second or two, the estimate appears in the digital display. Successive readings of a single board or a stack of same-species boards is no more difficult than moving the meter to different locations or different boards. There is no re-calibration required, no pressing of buttons, no time delay of any kind involved at all. It's that quick. Another example of Wagner's attention to user-friendly detail is the area on the front of the meter where the Specific Gravities of up to ten species can be written down for quick reference.

The MMC220 can provide moisture content estimates of 5% to 30% for woods with Specific Gravities of 0.20 up to 1.00 (to get an idea, Eastern white pine has a Specific Gravity of 0.35 and Black Walnut's is 0.55; the moisture content of a construction-grade piece of spruce would be about 15% to 19%). The unit is not affected by temperature or humidity, wood grain orientation or any applied the finish. It will even read through the plastic wrap that mills often use to envelop large quantities of wood for transport. It is only slightly affected (upwards) by surface moisture which should be wiped off in any case. Frozen wood with greater than 15% moisture content can be accurately scanned as well. Scanning depth is 3/4".

In addition to its simplicity, the MMC220 is small (4-9/16" long, 2-3/4" wide and 1-1/16" high) and lightweight (under 6 ounces), comfortable enough to use with just one hand and manoeuvre into tight spots. It has a hold function which allows it to take blind readings in difficult to access places and retain it in the digital display until it is deleted by the user with a touch of the On/Hold button. Powered by a 9 volt alkaline or NiCad rechargeable battery, the unit has a low battery (LO-BAT) indicator as well as a 60-second auto-shutoff.

Another couple of examples of the thought that has gone into the design of the MMC220 are the two membrane buttons which serve to keep dirt and moisture out of the switches. Grit, grime and moisture will inevitably infiltrate push buttons and slide switches but this shouldn't be an issue with the MMC220. Also, with its big, clear, bright digital display, the meter is very forgiving of low light conditions and oblique viewing angles. This tool was designed to be used.

I think one of the real advantages of this meter is that its learning curve is very shallow and very short. This not only means that you can pretty much use it within ten minutes of opening the box, but that a few months from now when you pick it up to use it again, you can do so without having to go through a lengthy, frustrating, 'where's-the-manual' re-familiarization process.

Ideally, I would have liked to have used the MMC220 on wood samples of known moisture content. The best that I was able to do was to use it on my air-dried musical tone woods that I've now had for almost thirty years, some spruce framing timber taken recently from the attic of a 100+ year old house, and some other boards about which I have a fairly good idea of moisture content. The meter appeared to provide accurate readings in all cases. In addition, being a researcher in a previous life, I know that the repeatability of results is one indication of reliability and in this regard, the MMC220 performed very well with the variability being well below 1%.

The CD that comes with the meter includes digital copies of the two hardcopy manuals, plus manuals for other meters in their product line, as well as an interesting article by Dr. Eugene Wengert of the Department of Forestry at the University of Wisconsin, entitled "An Industry Review: 10 Ways of Eliminating Wood Problems".

Wagner Electronics has been in the business of developing cutting edge moisture meter technologies for industry and private consumers for more than forty years, and they got their MMC220 right. The unit is a well-conceived, user-friendly, robust device that fulfills it's single raison d'être - to measure the moisture content of wood, which it does very well. Whether you're a furniture/cabinet maker, a musical instrument maker, a carpenter/contractor, a flooring installer, a wood dealer, an inspector, a serious hobby woodworker or anyone else who works with wood, the MMC220 can help you reduce wastage, call-backs, warranty claims and overall frustration. With the high cost of wood and time these days, this meter can pay for itself in no time.

Wagner Electronics warrants the unit against defects in material and workmanship for one year from the date of purchase, subject to the usual terms and conditions. It comes with a 100% satisfaction guaranteed return policy.

Reviewed November 2010, Gerry Tsuji