Moisture Meters

Moisture meters measure the percentage of moisture or water in wood to determine whether or not the timber is too wet or too dry to be used for furniture making.  If the timber is too dry you will get glue bond failure and if too wet it too will not hold, so using a moisture meter irrespective of whether you’re a hobbyist or professional is essential.

I admit that I haven’t up until recently ever owned a moisture meter and have to a certain degree worked wood successfully without one but I emphasise on that word to a certain degree.  Not every timber I worked was without its problems of cups, warps and bows, this isn’t necessarily attributed to moisture levels as I will describe below in more detail.  Not every timber I planed remained flat the next day.  Had I used a moisture meter prior to working that wood I atleast would have been informed of its moisture content percentage level and would have decided then and there whether or not this timber is workable.  However, not always is the MC level the culprit, as I mentioned in the Kiln drying article if the timber isn’t dried correctly it will form stress and regardless of its moisture content level you will face hard times working that piece.

Pinned versus Pinless

A pinned version consists of two pins that are proud on top of the meter, these two pins are inserted into the timber either face or end grain which is more common to take a reading.  A small electrical current is passed between the points, and the amount of resistance is correlated into a moisture content reading.  Moisture is a good electrical conductor so the wetter the wood the less resistance there is to the current.  The accuracy of a pinned version is affected by the variances in the naturally occurring chemical composition of wood species, but isn’t as affected by the density of species to the other.

A pinless version penetrates deep into the wood by using an electromagnetic wave through the area under the sensor pad.  This creates an electromagnetic field which then the meter produces a moisture content from the signal it reads back.  The real beauty of a pinless version is its non destructive, which means there are no holes bored into your timber and scans a much larger area than the pin styled version.

The debate between the two versions of which is more accurate has been an ongoing debate for years with only ever one outcome, pointing favourably towards the pinned styled version until recently.  With technological advancements, the pinless style is just as accurate with the added benefits of no holes in your timber as described above its non-destructive.  However, it always boils down to the quality of the device and there are many manufacturers out there producing both versions that range in price from $30 to $1000.

All companies regardless of version will make claim that their meter is the best in terms of accuracy.  Research and knowledge will quickly weed out the falsities of these claims and help you determine the accuracy or falsities of their claims.

So how do we know which manufacturer to choose from, well lucky enough for you I have done this research over many months and am providing a link for you www.moisturemeter.com where you can see for yourselves which brand is better than others.  These tests conducted are by experts and the methods they used are described on their website.  I urge you to thoroughly go through all the brands tested so you can make a truly informed unbiased decision, after all money doesn’t grow on trees even though the leaves are the same colour.

After extensive research of many, many brands I have opted to go with a Wagner MMC220.

wagner-mmc220

With this meter, you also receive a clip-on carry case.  Yes, this meter is fragile you cannot exert more than 2-pound pressure and if dropped from 4 feet or more will result in damage to the unit and will need to be sent back for re calibration.  I thought I’d point that out straight off the bat other than that, its accurate and measures moisture in the wood and not on the surface of the wood.  It measures softwoods and hardwoods as well as tropical species. In the manual, you receive they provide a specific gravity list of most commonly used timbers. If your timber isn’t listed they also provide you a link to where you can locate your timber.  I know you’re wondering just what is specific gravity? It’s the weight of a volume of wood divided by the weight of the same volume of water.  The higher the specific gravity the stronger the wood and more difficult it is to work and since we’ve jumped onto this topic, I might as well add four more property terms you will encounter on lumber yards’ website descriptions in different species.

Hardness is the resistance of the wood surface to damage.  For example you will see hard, medium, soft or very soft.  The higher the number the less surface damage it will experience.

Strength will determine how much weight a specific wood can support.

Bending Strength is the ease with which a wood can be bent and how much of its strength in percentage it will retain after it’s bend.

Movement is the woods movement across the grain so the lower the percentage the less movement across the grain there is and the more stable it is.  However, when there is a big difference between tangential and radial movement the wood is prone to cups, twists, bows and warpage.

If this wood movement is between 1 – 3% it should be stable but anything higher than that you will experience the above mentioned.

So here is an example of the descriptions you’ll see.

11_blue_gum

Blue Gum

Heartwood dark pink to red brown. Sapwood usually sufficiently paler to be readily distinguished. Texture moderately coarse and even. Grains straight or slightly interlocked. Gum veins common. Also, known as Sydney Blue Gum.

  • Density kg/m3 Dry: 850
  • Specific Gravity: 0.85
  • Modulus of Rupture Mpa Dry: 140
  • Modulus of Elasticity Gpa Dry: 18
  • Radial Shrinkage: 5%
  • Tangential Shrinkage: 9%
  • Hardness (Janka) (kN): 9
  • Finish: Good
  • Stability: Good
  • Durability: Durable
  • Susceptible to Lictus Borer: Yes
  • Machining: Good
  • Split Resistance Nailing: Good
  • Split Resistance Screwing: Good
  • Gluing: Good
  • Growing Region: Australia
  • Availability: Widely

Embolden and underlined are what to look out for, other websites will add further information of its blunting effects on tools, work ability and so forth but as your experience grows by working with various species you will come to know and expect each timber blunting effects, work ability and stability.

According to the information given the average percentage between the radial and tangential shrinkage is 4%.  This website claims stability is good when in fact it’s poor, but they can’t say that otherwise the laymen’s will not buy it.  With this timber, you will experience behavioural problems which means you must work fast to overcome these potential problems.  Basically, once you have it planed flat, by the end of the day your joinery and assembly must be complete.  In this case, you would have to break up your work and be realistic on how much you can complete within that given day.

Let’s look at one more example.

ng-rosewood

Rosewood

Heartwood can be either golden brown or a dark blood red. Sapwood pale yellow. Texture medium. Grain variable. The freshly cut wood has a fragrant odour often highly figured. Also, known as New Guinea Rosewood, Solomon Islands Rosewood.

  • Density kg/m3 Dry: 650
  • Specific Gravity: 0.65
  • Modulus of Rupture Mpa Dry: 95
  • Modulus of Elasticity Gpa Dry:12
  • Radial Shrinkage: 1%
  • Tangential Shrinkage: 2%
  • Hardness (Janka) (kN): 5
  • Finish: Excellent
  • Stability: Excellent
  • Durability: Durable
  • Susceptible to Lictus Borer: No
  • Machining: Excellent
  • Split Resistance Nailing: Good
  • Split Resistance Screwing: Good
  • Gluing: Good
  • Growing Region: Asia Pacific
  • Availability: Available

As an excercise you pick out the points of interest.

You will note that the stability is excellent with only a 1% difference.  This timber is not only attractive but durable and stable but does have reversing grain which isn’t mentioned in the description.  This is one of my most favourite timbers to work with.

It’s amazing how I never stick to the topic at hand but I felt it necessary and important to have added the above lessons as I’m sure not many of you would have known this.

So let’s get back to the unit itself.

The price of this unit in the US is US$395

https://www.wagnermeters.com/shop/mmc220-extended-range-moisture-meter/

In Australia on special for AU$416.90 including GST until March 2017 which it will then be $469.90

http://kevmor.com.au/wagner-moisture-meter-australia/2210-wagner-mmc220-wood-moisture-meter-extended-range.html

Don’t bother with eBay as they are selling it for well above $600 which is usually the case with eBay now a day.  If I see something I like on eBay I will always hunt around on google for a better price and 9 out 10 times I will always get a better price elsewhere.

For my Australian readers, Carba Tec is usually more expensive than items you can buy from England directly either through eBay or their websites which sometimes includes the shipping as well.  Complaints have fallen on deaf ears even though they made a solemn promise it wouldn’t.  With just under 10,000 readers of my blog worldwide and growing weekly I’m sure their hearing will miraculously return.  Praise the Lord.

Final thoughts

Price unfortunately for many of you is a determining factor in which product you’ll buy.  For many of you that is of that mindset usually ends in detriment that produces less than desirable results which, always leads to a disastrous end and possible loss of interest in the craft down the track.  When it comes to tools, quality should never be compromised due to lack of funds.  Hard work, patience and strict budgeting is the key to success. Just setting aside just $20 a week is a saving of $480 in 6 months.  This may seem like a long time but 6 months will go by with or without you budgeting so why not set yourselves goals.

You’re not children and I won’t treat you like ones, you know your own financial circumstances and need to think and act responsibly.  On the same token with some thought and foresight you can own many high quality tools if you move away from the I want it now mindset and learn to be patient and budget well.

I have no financial benefit from the above mentioned websites, nor do I have any financial benefit from you either, nor from this blog.  So there is no need for me to sugar coat anything when I tell you,  being a tight arse will get you nowhere, which reminds me of a video I once watched on YouTube.

A guy making a box, nothing fancy just a box.  He is claiming it only cost him $10 to produce,  which is a false statement as he hasn’t claimed labour, rent, electricity, taxes, packaging, shipping etc. but let’s go with it anyway.  He claims that this box will sell for $40 on the flea market but he’s not willing to pay $40 himself so how does he expect others to pay him the same.  Get the picture?  I hope so, maybe I could have worded this better but we are coming to a close and I really want to get on with my project.

One last point to make,  the Australian dollar is quite low, and the economy is quite weak irrespective of what my weak, irresponsible, dumb, lying government who only gives tax breaks to the wealthy, will say. For the US, this is a great opportunity to get good bargains.  This unit should cost you less if you purchased it from here than in your own home country.  When the Aussie dollar was stronger than the US I took advantage of this and saved hundreds.  So now you too have this opportunity for however long it lasts.   Think smart, budget well and be patient.

Thank you for reading and listening to my blog.

 

 

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2 thoughts on “Moisture Meters

  1. Very useful post. Thanks Salko
    I’ve been searching one myself, because I already had some moisture surprises after ripping a thick plank 😦

    Never the less an old fellow once told me about our local pine wood, “after dry, no matter what, your wood should be in your shop at least during 4 seasons before you built with it”

    Liked by 1 person

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