Customer Reviews

General Tools MMD4E Digital Moisture Meter

5 star:		(24)
4 star:		(13)
3 star:		(5)
2 star:		(2)
1 star:		(8)

 

 

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.

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. :)

i don't know how it is for lumber, but this has been great for firewood. makes it super easy way to figure out what wood to use first. highly recommended!

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.

We had a competent craftsman repair and replace logs on our family log cabin built in the 1930s. The Cedar logs installed were all new, and we wanted to coat them with a material that would keep them light & preserve them as long as possible. We chose Clear Rymar. Since it is important to apply the coating when the logs are as dry as possible, I purchased this item. It worked just as described, swiftly measuring moisture content. Tested it first after dry periods and as well as just after rainstorms. The variance showed it was doing what it was supposed to do. We then gave it to the professional painter who used it throughout his application. Prices vary much with these meters, this was reasonably priced and did what we needed.

This meter works as good as any Iv'e seen. I used it on lumber (Red Oak) that I had determined the moisture content by weight, using the oven dry method. The meter was within .5%. The turn on procedure is long - but once you know to hold the power on button for 5 seconds all is good. You can spend a lot more money but this works great for my woodworking shop.

I am a Painting Contractor and in Oregon need a good moisture meter to tell me what the level of moisture is in the house I am going to paint. I have used other meters that cost hundreds of $'s and they are not better than this one. At this price I am going to buy on for each of my painting crews.

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.

The general tools Digital moisture meter is an excellent item for the price. I bought it to test the moisture content of logs I obtained from a tree service to see if they were moist enough to use for growing mushrooms. By drilling holes in logs and inserting mushroom fungus (spawn) into the holes, mushrooms will grow from the logs for about five years. A 30% or higher moisture level is necessary for proper mushroom fungus growth in the wood.

That's where the moisture meter comes in, to determine if the moisture level is sufficient. For this purpose, the meter works well. It should be noted, however, that readings will vary with the location on the log being probed with the two sharp prongs and how far and forcefully the prongs are inserted into the wood.

It's not precisely accurate with every reading, but that's a function of the degree of penetration, the uniform force of insertion and the area tested (bark or bare ends). This meter would be also be great for determining the reciprocal of what I test for, namely, how dry is the wood for burning.

Previously, I had to saw a small piece from each log (much work), weigh the piece with a precision scale, then dry the piece on low for 24 hours in the oven, then weigh again to determine the moisture content. Now I can do this in a few minutes!

I recommend that, when using this meter, you push it into both ends of the logs AND in several spots in the bark with the same degree of force, and see if you get consistent results. Use the same force to push the pins, and try to get the same pin depth in each test spot in the wood.

A friend used it to check the extent of moisture in his basement carpet after he had some seepage. He was able to identify what areas of the carpet that needed drying so he could focus his fans and heaters effectively. After drying a while, he used the meter to determine which areas were fully dry so he could move his fans and heaters.

One final observation: Another reviewer complained about the meter not turning. My advice: READ THE DIRECTIONS. It takes about 4 seconds of holding the 'on' button down to turn the meter on or off. This is a battery saving feature.

Easy to use. Does what it says it should do. Seems to be accurate or at least consistant. Having no other tools to compare it to I don't know how accurate it is, but testing against itself in the same spot, it gives consistant readings, and in areas I "know" are damp or dry, it certainly reflects that. Good price.