I recently cut off a few small maple stumps (4"-8" diam) and they revealed some really nice color and figure. A few weeks ago, I cut a 3" piece off and turned a pen with it and it held up through the process very well.
Question is, with the 4-8" x 12" long stump portions, how can I tell when they will be dry enough to cut into blanks for turning slightly larger projects? It was dead standing when I cut it down, so the bound water should be dried out leaving only free water to dry out, right?
It's hard to know just how dry your wood is without a moisture meter. Even standing dead wood can have fairly high MC. I would go ahead and cut it up into blanks. If it is still wet, it will dry quicker in smaller pieces. As you open up the stumps, hold the cut surface to your cheek. You can feel it if the wood is still moist.
By the way, this is a Russ Fairfield tip for quick checking moisture content.
It is still damp to the touch. I have a Wagner 220 moisture meter, but will it be accurate on a blank 2" thick? Also, what would the specific gravity be, would that not also change from the original hard maple SG.
My Wagner 220 indicates it will read to 3/4" depth, but cautions not to try to read an area with defects so if the wood is "punky" it might not be accurate and the "book" specific gravity would not be correct. I think spalting alone would not affect it much. In my experience moderate changes in the species value don't make a huge difference in the MC reading.
But I use the meter only for a general indication of moisture content. A 4-8" diameter x 12" chunk may take many years to dry. It might dry much quicker if cut up in to smaller blanks but the rule of thumb for green lumber is one year per inch. Seems like much would depend on how long the tree stood dead.
If it's nice wood, I might just treat it as green and rough turn it to an inch or so thickness then wait for it to dry before finish turning.
Note that you can use the weight change method to check for moisture - periodically weigh the blank or roughed turning with accurate scales (every few months) and chart the weight. When it no longer changes it should be as dry as it's going to get and stable.
If you do want to figure the specific gravity of your wood, it is actually quite simple.
Cut a 1/2"x1/2"x10" section of the wood. Lower it carefully into a narrow container filled with water. With the wood floating, mark the level of the water on the wood. Measure the length of the submerged part. The specific gravity is the ratio of the submerged length to the total length.
If the wood sinks, you know for a fact that the specific gravity is greater than 1.0. At that point, I guess you would need to figure out some method of measuring how far the wood sinks. The specific gravity should still be the length of the submersion divided by the total length of the piece.
I neglected to mention that this process comes from "Drying Hardwood Lumber" from the Forest Products Lab. They don't take it any farther than I did.
