Can a moisture meter be used on a bowl that has been covered with anchorseal to get an accurate measurement? If so what would be a good meter to invest in?
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Moisture Meter
- Thread starter Ryan Sohn
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I never felt moisture meters worked for me. The pin type can only give a reading at the surface. Weighing the rough outs weekly until they stopped losing weight has been a better option.
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I agree. A small digital scale that measures in grams gives a much better answer.
Yes, either pin or pinless types can read through a thin surface layer. I have the Electrophysics model MT808 which is both pin and pinless. I like that I have both options, but so far I haven't used the pins.
http://www.electrophysics.on.ca
Ok thanks for the input guys. I have currently been weighing mine and wondered if it would be beneficial to check with a meter. Any idea on timeline to dry bowls that have been coated? I’m guessing up to 6 months or more for extremely wet bowls?
A moisture meter is a valuable component of the "big picture". Others have indicated the weight is the best indication of the process overall, and I agree with that, but that doesn't eliminate the need to know the MC as the starting point. A turner needs to know as much of the available information possible, in order to oversee the process of moisture stabilization. Eliminating the guess work is an important part of the process.
-----odie-----
-----odie-----
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It depends on where you live. Here in north Texas average size maple bowls dry in three months. Extremely large ones take about six months. I also turn a lot of mesquite which can be turned in a single session.
Awesome input, thanks guys!
Not to my way of thinking Bill.......it's important way of assessing the data......but, I understand that not all turners have the same methods of determining the moisture stabilization process as I do.....
I bought one at Home Depot. Makes me look like I know what I'm doing when a customer comes to pick up a bowl from the rough turned ones drying. I can steer them to the right one that I want to sell with the moisture content, LOL. Seriously, I mostly go by the date on the bowl. Minimum 6 months for Koa... I have too many to weigh and keep track of that..
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I have used a pin moisture meter for many years.
I check using the pins into the tenon. The tenon dries a bit faster than the bowl but it is close enough.
I don’t turn lots of dried bowls but I have a shelf full so I can test the moisture quickly if I’m looking for one to finish turn.
I use the meter to test ball blanks. Pop them in the microwave if the MC is to high.
Weighing is more accurate but you have to weigh regularly and record the weight.
In a controlled environment when no weight loss is seen in two weeks it is dry to that environment.
You can use a chart to find the MC for that environment?
I check using the pins into the tenon. The tenon dries a bit faster than the bowl but it is close enough.
I don’t turn lots of dried bowls but I have a shelf full so I can test the moisture quickly if I’m looking for one to finish turn.
I use the meter to test ball blanks. Pop them in the microwave if the MC is to high.
Weighing is more accurate but you have to weigh regularly and record the weight.
In a controlled environment when no weight loss is seen in two weeks it is dry to that environment.
You can use a chart to find the MC for that environment?
Most of the wood I turn is already dry, however, I do turn green wood when it is available too me. I have a (General) pin type MC meter that I use during the drying process. I also weigh the bowl once or twice a week and record the weight as it goes through the drying process....... I store green bowls in a paper bag with dry shavings.....I do use anchor seal on the end grain of stored green logs.
Bill......You can probably get by with a formula like that......and, whatever works for you is ok.
Eventually, there will be a problem with it, because all individual pieces of wood are unique in their characteristics. Weight is a better indicator of stabilization, than time. Weight is a direct measurement, while time is based on theory. Wood that is dense, or has tight swirly grain vs straight plain grain, different species, domestic or exotic, differing initial MC's......all will require monitoring in a direct manner. The only real way to reliably know for sure if it's stabilized, without room for error......is by weight.
-----odie-----
I think if a turner uses mostly the same species of wood, or similar, it would be fair to say a formula based on time should work very well. I turn a lot of domestic maple, and most of it is partially dried, and has MC around 14%-18%. In that particular case, I could use a formula based on time, and it would probably work very well. In my case, I purchase wood from around the world......very different starting MC, radically differing wood density, and differing ability to release that moisture into the atmosphere. The only direct method of determining whether stabilizing has occurred......is by weight.
I currently have 63 bowls in the seasoning process, and several hundred that are stabilized, and ready for final turning. Every one of them are logged onto a file card......along with other information, such as an inventory number, cost, harvest location, species, size, source, flaws, date of purchase, etc. There is the initial MC, which is done with a pin type Lignomat meter. That's the extent of using the Lignomat. The initial metered MC is useful information, as it gives an idea of what to expect during the seasoning process. From there, I log the weight each month (I'll do that today!
). For most wood, if the weight remains stable, +/- about 3-5 grams for three consecutive months......then I call it stabilized. It's then ready for final processing. In a few cases, I wait for 4-5 months.......it depends. The time of year is part of the equation, as well......because wood releases MC at a slower rate during winter vs summer.
Once the roughed bowl is stabilized, sometimes it remains unprocessed for extended periods, while at other times, I want to work on it right away......all depends on how I choose to discriminate!
Regardless, that file card with all the information is valuable bit of data that helps me to know everything I can about one individual bowl.
-----odie-----
I currently have 63 bowls in the seasoning process, and several hundred that are stabilized, and ready for final turning. Every one of them are logged onto a file card......along with other information, such as an inventory number, cost, harvest location, species, size, source, flaws, date of purchase, etc. There is the initial MC, which is done with a pin type Lignomat meter. That's the extent of using the Lignomat. The initial metered MC is useful information, as it gives an idea of what to expect during the seasoning process. From there, I log the weight each month (I'll do that today!
). For most wood, if the weight remains stable, +/- about 3-5 grams for three consecutive months......then I call it stabilized. It's then ready for final processing. In a few cases, I wait for 4-5 months.......it depends. The time of year is part of the equation, as well......because wood releases MC at a slower rate during winter vs summer.Once the roughed bowl is stabilized, sometimes it remains unprocessed for extended periods, while at other times, I want to work on it right away......all depends on how I choose to discriminate!
Regardless, that file card with all the information is valuable bit of data that helps me to know everything I can about one individual bowl.-----odie-----
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I have a digital scale that goes to 150#. A 24" Pecan or Cherry bowl roughed out to 1 1/2" thick can weight 50#. I Anchorseal, weigh and date the bowl on a piece of paper that I put into the bowl. I start weighing the bowl at 6 months every 3 weeks and when I get two weights that are the same, it's ready. When I turn green bowls I have 20 or 30 of various sizes since I use a coring system. I only need to weigh one bowl of a given size to determine when they are all ready.
Howdy Paul.......
I've got a question for you, or anyone who would like to input. I was under the assumption that digital scales were more accurate with the less range of weight. Am I mistaken? I recently bought a new digital scale that goes to about 75#, and I believe the old scale was 38# max. Is there any difference in the accuracy of these scales? IOW, if a scale is of a higher capacity, is it less accurate, if we need to know within a few grams?
-----odie-----
Odie I think capacity is just that , the max weight for accurate weight readings. The accuracy should be the same from 0 to max weight.
I have used a cheap Harbor Freight pin type moisture meter for about 5-years and changed the batteries last year and it still is working fine. I usually use the meter when I am using different woods for a segmented piece, a green turned bowl is easier to date and weigh to determine when the moisture content has stabilized.
I have the pin and the pinless type moisture meter. I haven't use the pin one for quite a while. I do use a small scale that reads in mg. I fine that the moisture meter reading has a lot to do with where on the bowl you check. How long I let one dry also depends on what it is like NE or cut top bowl. A little warping isn't much of a problem on most NE bowls. I dry my rough out for a few weeks in paper bags, large cattle feed bags. If i'm in a hurry I microwave the bowl but it still is a slow process and a lot of work. I microwave in a plastic garbage bag on high for a few minutes then cover it up with an old winter coat for about 15 minutes. I then take it out of the plastic bag and turn the bag inside out and put the bowl back in the bag and microwave for a few more minutes. I keep checking the weight as I do this. It works and is time consuming so I don't do this unless there is a reason. My bowls usually sit on the floor for a few months uncovered mostly because I don't have the time to get them final turned. Different woods dry faster than others, some crack worse than others. Where your wood comes from like is it freshly cut tree or from a store. Some wood has more moisture depending the season it is cut. If it has layed on wet ground one side may be wetter than the other. If you do NE bowls that have layed on the ground for a while, the bark is pretty sure to come loose. There is no one answer to drying wood.
I totally agree with the weighing method that I have been using for about 20 years. I have an old digital mail scale the was being thrown out because the mail rates could no longer be updated. I rough turn green wood to a uniform wall thickness and coat with anchor seal on the exposed end grain and then weigh the piece and record the weight and date taken on the tenon or a piece of paper. The time between weighings may start at a day or less and gradually get longer depending on the relative humidity in your drying room. In my location in northwestern Minnesota the winter months will be very dry inside and therefore do the most rapid drying and the summer is high humidity which has caused some pieces to increase in weight.