There are about 3 grades of this PMC. A thin, a Thick or hard and also the binder more like a watered mix. This is mainly for connecting edges together. It is very expensive about $30.00, but there are different brands which may be priced lower. But it all comes out of Japan. In a package you get a ball about 10 grams worth I think which in looking at the amount it is the size of a super ball (One of those very rubbery balls). You can make out 2 or 3 rings with it. It is not recommended to drill it, but your holes should be made before firing.
The temps for firing are about 1250F to roughly 1750F. Depending on which mix you have you and can fire it by either a propane torch or a small kiln. Lower temp with a torch can be about 2-10 minutes. The best way to work it is design what you want and make sure it is slightly oversized it shrink 28% which could be a could of thousands or hundreths can't remember, after firing. But before firing , let dry over night and will be firm to touch. Then fire it depending on mix you have at specified temps. When it is at a certain temp the binder will burn of creating a flame. The piece needs to be fired til a slight red flow or orange glow then take away or turn off kiln. Some kilns can be set a timer which some also have a cool down cycle too I think.
When the piece has finally cooled, then take a small fine wire brush or course steel wool to take away the chared binder. Then there you have you full silver piece. This PMC would work great for creating you own center rings, but I do not think it is best to turn it.
I hope I have some of this right, I was looking into it myself to design some goth/keltic jewelry.
Barnes & Nobles should have a few books on it. The one local to me has 4 different and thick books on it.
Later,
Ray