I'm working on a small -- 6" diameter -- cherry bowl. Moisture meter says this blank, rescued from a hunk of firewood, is 22%. I'm about done roughing it and will coat it with anchorseal. At what moisture percentage can I finish the turning? About how long should I expect it to take to get to that point?
Lawrence.........
There are various methods turners use to conclude a Cherry bowl will be dry, and ready to finish turn. Some finish turn at a higher MC (moisture content) than I do. Those who do tend to use the higher MC, and degree of warp they'll get advantageously in pursuit of their own turning style. This is fine, but it's my objective to stabilize the MC to the ambient atmosphere at my location. I do this, because I would rather deal with the least warp possible within the confines of natural seasoning methods. In doing so, the lesser degree of warp is helpful towards my style of turning. Finish cuts are more controllable, and sanding a bowl that is as perfectly round as possible is better for the fine finishes I get.
I initially started out measuring MC with a moisture meter exclusively, as you are doing......and, finish turn when it's below, or around fourteen percent. This method didn't work out for me as well as I'd like, so I now use the moisture meter for getting a "ball park" idea of how the seasoning process, and time involved will pan out. After the initial moisture content reading, the bowl is roughed and completely anchorsealed. I seldom anchorseal any less than the entire roughed bowl......the exceptions to this would be bowls that are initially under around fourteen to sixteen percent to start with. There, I may choose to anchorseal only the endgrain......or, not at all.......it all depends on the wood species, and grain configuration. Denser woods usually have total anchorseal, even though they meter an initially low moisture content. I'm a little more lax with wood that is already low in MC, and the species tends to dry with minimal problems......but, nothing is chiseled in stone! ......use judgement.
Now, my method is to log monthly weighings, and when I get three consecutive months of no loss of weight, I call it good and consider the roughed bowl to be ready for finish turning. I don't always use the moisture meter at this point, but when I do, the roughed bowl is seldom more than twelve percent MC. It's not the percent of moisture content that's important here......it's that the roughed bowl has stabilized to the environment I have at my location.
If a bowl does not warp to some extent with the final turning,
it's an exception to the rule. My objective is to keep the warping to the absolute minimum, and stabilizing the MC to the ambient atmosphere is a better indicator of that, than is an arbitrary number from a moisture meter that will supposedly cover all species, sizes, shapes, and initial moisture content.
Along with my Mini Ligno E for determining initial MC, I use a postal scale for monthly weighings.......and these scales are very common, easy to get, and are plenty cheap! Many of us have both the scale and a moisture meter........and, that's what I'd suggest. Either one will get you from A to B......but, you have the best overall predictor of what any individual roughed bowl will require, and confirmation of stabilization, if you have both.......
ooc