Moisture question for green bowls

[Bill Summerlin]

I just bought a moisture meter to check my green turned bowls. Just to check on the meter, I checked some walnut that has been in my shop for 27 years. The walnut was at 15%. I live in mississippi where the humidity is high in the summer time, but does that sound right to those of you who use moisture meters. If so, realistically, at what reading should I finish turn my bowls? Thanks in advance for your help.

[Dale Bonertz]

That sounds about right. I kiln dry bowls and get them down to 7% to 8%. When they leave my shop and go to yours I am willing to wager they would go up to around what you are speaking, 15%. I believe you are OK to turn wood at 18% or less. Wood will always gain and lose. In your climate you may play heck to get one down to 10% to 12% at anytime. Go for it and have fun.

Dale

[David Dockstader]

Just don't ship any of your completed bowls to Phoenix!

[Lee Koepke]

I have gotten to the point of weighing my rough-outs. When the blank stops losing weight, its generally 'moisture stable'. Of course that doesnt help your particular case!

[Fred Belknap]

Bill I don't know the type of moisture meter you have but mine and I suspect most are the pin type and they don't do a good job of reading the moisture content of wood that is in block form. I suspect if you cut a slice off one of the blanks and checked the interior that the moisture content would be quite a bit higher. If you rough turn the walnut you will still get some movement. I weigh my rough turnings and when they quit loosing weight I consider them dry enough to finish turn. Walnut seems to dry slower than a lot of other wood, my guess is that because it is so porous that the outside acts like a layer of insulation to the interior. My walnut blanks start cracking after about a year in the barn.

[Michael Mills]

I use a meter and when drying I just stick them in the foot right through the paper bag. The pins are 1/2" long and the side grain loses moisture slower so I feel I get a pretty good reading.
Hear is a link to equilibrium and the city chart starts on page 7.
For me it is 12 -14.5% so anything less than 15% is good for finish turning for me. Then I can open the bag and find out what I will be turning.:)

http://www.fpl.fs.fed.us/documnts/fplrn/fplrn268.pdf

[Bill Summerlin]

Thanks dale, I appreciate your response.

[Bill Summerlin]

Very helpful reply, thanks

[John King]

It's not about the absolute value for the moisture content of the rough bowl. It's about the equilibrium moisture content for your location. Equilibrium moisture content for a rough turned bowl in Phoenix, AZ, (very dry climate) will be dramatically different from Houston, TX (high humidity climate). And in Houston the equilibrium moisture content will be different if the rough turned bowl is dried in ambient air in the garage/shop/studio or in an air conditioned environment. So, toss the moisture meter far into the darkness of the night. It's simply not accurate for this application. Weigh the rough turned bowls on a regular basis. When the weight remains constant for a couple times, the rough turned bowl is at equilibrium moisture content for the current environment and will not get any drier unless the drying environment is changed. - John

[Richard Jones]

I check some surrounding wood that I know is dry, like a piece of door trim or an exposed wall stud. If it's close to what the bowl reads, I figure it's OK to re-turn. Methodology has worked pretty well for a number of years..............

I will have to respectfully disagree with tossing the meter into the night........If a rough turned bowl is at 10% and door frame in my shop is 10%, I figure it's OK to re-turn. Same "the rough turned bowl is at equilibrium moisture content for the current environment and will not get any drier unless the drying environment is changed." applies to this method as well.

[David Gilbert]

Michael Mills gave a link to the Wood Handbook that is published by the US Dept Agriculture.
http://www.fpl.fs.fed.us/documnts/fplrn/fplrn268.pdf

In the article, Table 1, shows a listing of temperatures and relative humidities and what equilibrium moisture content is in wood. Table 2 gives a listing of locations around the US with equilibrium moisture content as a function of the month.

This information in Table 1 is also available in Lee Valley's Wood Movement Reference Guide #50K24.01 for $9.50. My reading of the information here indicates that you must live with extreme heat and humidity.

In any event, weighing the bowls is a very good way to follow their drying. I have a cheap Harbor Freight meter but haven't really found it to be of much use.

Good luck and stay cool,
David