19 Nov. 2007|
Moisture meter wood floors,wooden boat plans for beginners,child's twin bed frame - .
Pin-type moisture meters function by measuring the electrical resistance between two electrodes. One of the advantages of using a pin-type moisture meter with insulated contact pins is that they provide the best means for identifying the precise location of moisture in sub-floors or kiln-dried lumber.
A popular pin-type meter among flooring contractors, woodworkers, furniture manufacturers, Quality Control inspectors and small lumber mills is the Delmhorst J-2000 Pin Type Moisture Meter. Some conditions such as wood thickness, wood species and multiple layers are particularly difficult to penetrate with standard contact pins.
Using a pin type meter with insulated pins is most effective in determining moisture gradient (the difference between shell and core moisture content). Choose a pin-type moisture meter that features simple controls and a display that is easy to read.
For more information on choosing the best moisture meter for your flooring needs, call 877-DELMHORST (877-335-6467). Do you think this pin type moisture meter can also read accurate for dry food etc like frozen meat or biscuit..
I have always found pin-type moisture meters to be the most reliable method of measuring moisture in flooring, particularly at sub-floor level, and I have worked as a flooring contractor for many years. AccessoiresMCS-1Moisture content standards are great for verifying that your Delmhorst moisture meter is in calibration. Using a Slide Hammer Electrode like the one pictured below allows easy pin penetration in hardwood floors. They are so simple to use that there is no issue with retesting the wood as many times as is needed to make sure that everything is ok.
In a nutshell, moisture content (%MC) compares the weight of the water within a piece of wood against its oven-dry weight. With built-in wood species correction and temperature correction, the J-2000 is an extremely versatile tool for a great value. With two electrical resistance values (12% and 22%) to test your meter against, you can be sure that your readings will stand up to the strictest standards of accuracy. It only makes sense, then, that you should carry the one essential tool that allows you to detect and battle moisture problems—the moisture meter. In a perfect world, all moisture content testing would be completed by an "oven test" where a piece of wood is weighed before being placed into an oven at 212 degrees Fahrenheit (100 C) for around 24 hours. This resistance is measured in ohms and then converted to a reading expressed as % moisture content.
Digital displays also make it very easy to see the exact moisture content of the wood, which allows decisions to be made about how to progress and reduces the need to correct mistakes later. Although it is a relatively simple tool to use, one mistake made using a moisture meter can prove to be a costly one. Readings are obtained by inserting pins into various depths or areas of the flooring and sub-flooring. Here are seven common moisture meter mistakes and how to avoid them.1) Using the Wrong MeterDifferent meters are calibrated to test the moisture content of different materials.
Carry two meters to the job site if you know you will be working with both types of materials, and learn how to properly use each meter. For added convenience, some manufacturers offer models with both wood and concrete moisture meters combined into one. Generally, both pin and pinless concrete meters qualitatively measure the relative moisture content of the slab, meaning they indicate which areas are dry and which are still wet. Know their limitations, one being that concrete meter signals can only penetrate—at the most—an inch into the material, failing to reveal moisture problems deeper in the slab that can migrate up into your flooring after it's installed. Also, any fast-cure additives or vapor retardants added to the concrete may give your meter a false reading. Consult the manufacturer to determine if further tests are needed, such as the ASTM F 2170 test of drilling a hole into the concrete, waiting 72 hours and then measuring the moisture content with an in-situ probe or using a relative-humidity meter.Using the right meter for wood can pose a different set of challenges from concrete. Evaluate which meter best serves your needs for the type of work you do.Pin meters feature two pins protruding from the end of the meter, between which an electric current travels and measures the moisture resistance in the wood. The pins can either be hammered or stuck into the flooring, and they must be placed in the direction of the grain for the best reading.
The pins can be driven into the flooring at varying depths to determine the moisture content of each section of a particular board, making it easier to find the exact source of the moisture. Some meters feature pins insulated with latex or rubber to give a precise measurement in a specific location, which is ideal for gradient testing (measuring the moisture content of the wood at different depths of the board after installation) because the readings come only from the exact area between the ends of the pins. It transmits low-frequency signals down into the flooring, which travel back up to register the average moisture content of the entire plank.
But for any flooring with thicknesses less than what the meter is designed to measure, the meter may measure the subfloor underneath and give an inaccurate reading. The pinless meters are considered more convenient because they don't require hammering or insertion of pins and are preferable to the pin meters for prefinished flooring because they don't leave any holes. For materials made of multiple species, such as engineered flooring or plywood, testing methods vary, so consult the flooring and moisture meter manufacturers on the proper way to test for moisture content.2) Not Properly Maintaining the MeterIt doesn't take much to ensure your moisture meter gives accurate readings, but there are a few things to keep in mind for maintenance.
Occasionally, the meter's calibration can be lost, in which case you should send it back to the manufacturer for recalibration. If you use insulated-pin meters, be sure to change the pins frequently, since every time the pins are stuck in the floor, some of the insulation is scraped off, eventually making the meter more susceptible to inaccurate readings. If they measure the acclimated flooring, the middle of the subfloor and once under the window, they think they have covered all their bases.
By measuring so few areas, these contractors are less likely to find trouble spots in the floor.
Test the areas most conducive to moisture—along the exterior walls, under windows, around fireplaces, in exterior doorways, anywhere plumbing comes up through the floor and anywhere there may be discoloration.
Testing the flooring before installation gives you a good idea of what happened to it since it left the warehouse. The more measurements you take, the better you'll be able to determine the overall moisture content of the flooring.
Record the readings from the subfloor and the flooring with either a spreadsheet or with photos of the meter on the flooring with the reading prominently displayed.
This shows you properly measured the moisture content on the job site in the event any moisture-related difficulties arise later.5) Not Interpreting Data CorrectlyOf course, all these measurements are meaningless unless you know what to do with them. Many wood moisture meters aren't calibrated to a particular species or, if they are calibrated, it's to a generic specific gravity such as that of Douglas fir. You need to adjust the readings to the flooring you're working with to determine if the moisture content is acceptable for that particular species.Consult a chart or do a calculation provided by the manufacturer to get the correct moisture reading. Some meters on the market can calculate this information internally—all you have to do is punch in a certain code.6) Not Knowing the Area's MCTo interpret the moisture meter's data, you need to know the acceptable moisture content for the area of the country you're in.
For example, the meter may read 12 percent moisture content, which is within the normal range for some regions but which is too high in drier, lower-humidity areas.
See the "Moisture Content of Wood" chart on page 66, which lists acceptable moisture contents for wood at certain temperatures and relative humidities. Some contractors try to rely on old-fashioned methods of feeling the wood or trusting that the acclimation time was enough.They may not want to invest in a good meter, or they may be under pressure from the general contractor to get their work done faster.
Whatever the reason, with the great potential for problems and the myriad meters available in different price ranges, styles and functions, there's no excuse for installing flooring without a moisture meter.By learning from the mistakes of others, you can effectively use this tool to protect your floor from the disastrous effects of moisture—and therefore from costly callbacks.