I also have a 8x8x2 inch piece of genuine Leopardwood (Roupala species, bought elsewhere), unwaxed, advertised as 12% moisture. I carefully measured its dimensions, did the math, and it weighed precisely (within a gram) what it should have at 12%. In the eight weeks that I've had this piece, it has changed from 1389g to 1355g. I am waiting for the weight to stabilize before turning.
It had not occurred to me that, if in fact my Goncalo alves is not as dry as advertised, turning it now may actually decrease the chance of it checking. Thanks for that advice.
Frank, the initial MC reading from a moisture meter only gives you an idea of what to expect. Equilibrium at your location may not be the same as someone in another climate......
but, it's all you have to work with! The wood is only capable of stabilizing to the climate it's in. The time it takes to stabilize will vary with species, grain orientation, etc. As long as it continues to lose weight, it hasn't stabilized yet. In some cases, I've had anchorsealed roughed bowls slightly increase in a given monthly weight, if the weather is very cold or rainy. Then it continues to lose weight for months after that. The only true way to know if the roughed bowl has stabilized, is if the weight is stable for a 3-5 month period. (I usually give it more time to be sure, during the late fall and winter months. A stabilized roughed bowl may fluxuate up and down a few grams/or 1/10th ounce, or so......this is common.) Because the seasoning process can be radically different for individual pieces of wood, this isn't an exact science. Your gut feelings sometimes have to come into play......but, if there is any doubt, give it a couple more monthly weighings to confirm.
KNOW that it's stabilized, or you're destined to lose more bowls than you'd be comfortable with. Even the best of turners are going to lose a few, but if your successes are around 95%, or better, then you're doing about as best as can be done.
Time is your friend, so give it plenty of leeway. I have a Camphor burl roughed bowl right now, that has been seasoning for well over two years, and continues to lose weight a little bit every month. Some other turners probably would have final turned it by now.....and, probably would have lost it!
That Macassar Ebony is a tough one to season without cracking, as is all of the Ebony species. I have had them crack after roughing/anchorseal. You must monitor it like a hawk in the initial stages, to deal with any spontaneous cracks. If a crack is caught when it's still very small, I've found that an epoxy seal on the crack immediately, will arrest the crack, and you can likely turn it away on the final turning.
These days, I rough out kiln dried blanks with a MC of 12-14%, or less. (Most turners don't bother to season KD blanks.) These I do not anchorseal, but I monitor the weight for a minimum of 3 months before final turning. Some of them do lose some weight, and take a little longer.......this, IMHO, is a good habit to get into.
Don’t wait for blanks to dry.
Good advice from Doug........get those wet bowl blocks roughed and anchorsealed right away. If there is going to be any cracking, the chances of that happening is much less, if the MC is high, and the roughed bowl is anchorsealed right away. The purpose of the anchorseal is to dramatically slow down the moisture loss. This enables the roughed bowl to better withstand the internal stresses it will endure during that seasoning process. Again.....time is your friend!
-----odie-----