Woodworking Talk banner

1 - 4 of 4 Posts

·
Registered
Joined
·
3,212 Posts
Discussion Starter #1
I was intrigued by the method of weighing a board periodically and monitoring the weight loss to determine when the moisture content is at it's lowest, or at least at equilibrium. That made me wonder,,,, could moisture be determined by calculating the volume of a turning blank and comparing it's weight per cubic foot to the published density for that species?

For example, Let's say I have a 3" X 3" X 12" piece of marble wood.
The published density for a cubic foot of dry marblewood is 62lbs/cu ft.
A 3" X 3" X 12" piece of wood is 1/16th of a cubic foot.

So, if my blank weighs 3 pounds 14 ounces, it should be dry, right?
 

·
Senior Member
Joined
·
7,222 Posts
Published densities are likely an average.

I have boards of the same species which are very different in weight. This is due to factors such as sap wood vs heart wood, tighter growth rings due to better climate for the tree etc.

Look at the end grain of your boards of a given species. I expect the ones with the most growth rings will be heavier than the ones with fewer growth rings.

I would use either weight measurement over time, or purchase a moisture meter.

I purchased this one from Lowes as it was the lowest price I could find. This is accurate enough for my needs.

http://www.lowes.com/pd_78059-56005-MMD4E_0__
 

·
Registered
Joined
·
3,257 Posts
I'd be afraid of that because trees vary in density. I think the value they give is probably an average. A good example is locally grown walnut. I turn a lot of it. I'll get a log that turns like the wood is fairly dense and then the next log will turn like it's a softer wood. The both look the same but I'll bet if I weighted them they would be different.
 

·
Registered
Joined
·
470 Posts
In theory yes, but as mentioned may not be very accurate.

If you are interested in the weight method you can use it by obtaining a sample but not from an exposed end. Do as you originally were considering and weigh the original sample and compare to the dried sample. If I need moisture accuracy I use my powder scales and weigh in grains. This allows a sample to be dried in the microwave in just a few minutes or sun dried in a couple of hours using the afternoon summer sun.
 
1 - 4 of 4 Posts
Top