I’ve had to change ingredients for one of my favorite glazes. The recipe’s been around for years, and I’d been using the minority one that called for G-200 feldspar. Custer spar is the typical ingredient and a typical subtitute, and looks fine so far. There are other variations among batches, though. I’ve used dark rutile and light rutile, and there are several varieties of iron oxide in the glaze kitchen. They’re all pretty and fit well; the rest is personal preference.

Woo Blue (I truncate it for fun) has a wide range of color and looks great in the soda kiln, and not bad in c.10 reduction. Here are some macro shots of surfaces. All these were fired in the soda kiln. Be aware that although all these effects are visible by the unaided eye, the image on your monitor may be quite a bit bigger than real life!

Two bowls, about 6 and 8 inches across.

Three whiskey cups, each about 1.5″ across.

Three pinch bowls, each about 2.5″ across (perfect size for a teabag, bit of soy sauce, or to grind pepper into).

Buildup of rutile above the field of glaze. Inside edge of tumbler, image 1-1.5″ across.

Outside of a tumbler, the dark blue’s nice. Image about 1.5″ across.

Edge of a whiskey cup; this reminds me of a starfield being so dark. Image about 1″ across.

I like the little rivulets of glaze. Inside of a whiskey cup, image about 1.5″ across.

Like barnacles. Inside of a bowl. I’m guessing the image is 1-1.5″ across

Waterfall effect, image probably 2″ across.

An astonishing and really lovely effect is crystal formation. This is usually done deliberately and during cooling from much lower temperatures; I’ll have to do some reading and pondering to guess how it happened here. A couple of different bowls have these. This image is 2-2.5″ across.

This area is 1.5-2″ across.

Closeup of above, about 1/3 from the left horizontally, vertically about center. I’m glad to have gotten this shot in focus. Image is, I believe, under .5″ across.

This really shows off the abilities of my digital camera, as well. It’s the pocket-sized Panasonic Lumix.

Note on 13 Dec 07: I didn’t consider this earlier, but I may have removed some of the soluables from my most recent batch of glaze. As I sometimes do, i made the glaze with more water than necessary, and skimmed quite a bit off. Further consideration of the glaze chemistry will answer this. I am, however, quite pleased with my results.

Note 2 on 13 Dec 07: Dark and light rutile are calcined and uncalcined. Again, further study needed, but it does make a difference.

Note 3 13 Dec 07 - the waterfall and rivulets, when more extensive, are commonly known as hare’s fur.