Wednesday 27 July 2011

Moisture Meters - firewood, woodworking


We were getting hardwood floors installed - or so we thought - when the installers notified us that they could not do the installation because the wood in our house had acclimated to 6.4% moisture and our subfloors were at 12.8% moisture. The installer found a leak in our water softener line which we got fixed the next day. Unfortunately, we had no way of knowing (ourselves) when to call the installer back. Hence, we purchased this meter.



As far as we know, it works great. We aren't too concerned with the overall accuracy of the instrument, +/- 3% is just fine for us as we're looking to compare the difference between two materials in our home (assuming the error is consistent between those readings). The resolution of the meter is 0.1%.



Other things you might want to know:

- It comes with it's own 9v battery.

- It measures wood between 5 - 50% and 1.5 - 33% for other building materials.

- It has a hold feature which allows you to save the current reading so you don't have to keep the meter jammed in the material you are measuring.

- It beeps to let you know when it is done measuring. (Although, you can turn this off. We did accidentally and then figured out how to put it back on. We don't know why, but it has 8 different tones from which you can select.)

- It has a toggle button between measuring wood and concrete (or other building materials).

- The instruction manual is easy to read and follow. They come in English, French, and Spanish.

- It uses a two pin system to measure the electrical resistance of the material between the two pins. This is then calibrated against moisture content to give you the reading as a percentage. This means that it will make two small pin holes in the wood you are trying to measure. Therefore, if you are concerned about the holes, consider a "pinless" moisture meter, which are much more expensive.



The instruction manual lists other uses such as testing the moisture content of powders (for any scientists out there who need to measure such things for making standard solutions from scratch) and to test the dryness of a wall or furniture before painting or finishing. It also shows instructions for how to track down a leak using the meter. There's a funny picture in the instructions with the caption "be careful not to hurt your hands on the pins." Although, I did "test" the moisture content of my husband's leg. Don't worry, I didn't draw blood.



Overall, for the price, the features, and the product functionality (so far), I would say this is a great buy. Also, we got it shipped quickly via Amazon.com. It arrived two days after we purchased it. Yay!



UPDATE (7/31/2010): The pins broke when we were testing some brazilian walnut - one of the hardest woods out there. But I read in the instruction manual that pins were replaceable. I emailed General Tools through their website and got a quick email back. Less than a week later, I had two new prongs FOR FREE in my mailbox. Customer Service was AMAZING! The replacement prongs are much better than the ones that came with the meter. The new ones are shaped like little cones and have worked great on the harder woods. General Tools MMD4E Digital Moisture Meter

I bought the General Tools MMD4E Digital Moisture Meter to check the moisture of some flooring and trim moulding for house I am building. At the price of this product, I don't expect much in the way of absolute accuracy. Instead what I want is relative accuracy. In other words, I don't care if the wood has 8% or 10% moisture content. What I want to see is, what does the wood do over time. Once the reading stops dropping, the wood has mostly gotten as dry as it is likely to get in its present location. I tested the meter by taking a variety of readings to see if I could reproduce a giving reading. I went from dry wood to wet and back to dry. It seemed to be able to reproduce readings with a reasonable reliability.



The meter has a peculiarity that I think is responsible for another reviewer thinking his meter was broken, resulting in a 1-star rating. If the meter has not been turned on for a while, you have to hold down the on/off button for 4-5 seconds to turn the unit on. I've used a number of products which require you to hold down the power button for a prolonged period to prevent turning it on accidentally, but nothing as long as this meter. To make matters worse, the documentation says nothing about this feature. I can easily see why some people might think their meter is broken. A strange twist on the on/off is that if you turn the meter off, then turn in right back on again, you only have to push the power button for about a second for it to turn back on.



I rated this 4-stars because of the accuracy Vs resolution of the display. Why do they have a display with a resolution of 0.01% on a meter with an accuracy of +/- 3%? In trying to reproduce the same reading multiple times I typically saw +/- 0.5%. Realistically the meter should not display readings to a tenth. Sadly, many people do not bother reading directions, and as a result they may believe that the meter is far more accurate than it actually is. (The skeptic in me wonders if that was the intention of the marketing department.)



Now if only the meter would dry some of my trim boards that are at 25% moisture down to 10% so I can start trim-out. :)

Once I saw my emergency restoration people with one of these I had to have one. This no frills low priced moisture meter does the one thing I bought it for, it tells me where the waters coming from and to what extent. The meter is easy to use and accurate, in dark places the green, amber, red light make it easy to detect the wettest concentration of moisture.

I've used this meter for several months now and like it. This is the second moisture meter that I have owned. The first one came on as soon as I opened the top which was nice because all you had to do was pop the top and get a reading for my split firewood. That meter suddenly quit, couldn't fix It took a little getting used to turning this new one on because I had to wait for the meter to turn on. It has an auto turn off in about three minutes but there are times when I'm not using it in that short of time. Overall, I think that it is worth a 5 because it has a nice large readout and it has a hold button for when you are reading in a low lighted area. It takes a nine volt battery. As far a accuracy, it provides me with a good ballpark reading for the firewood. - Woodworking - Moisture Meters - Firewood - Hardware'


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