This recipe is wildly unusual (for an explanation see the info page at plainsmanclays.com, link below). Crystal Ice is a product of a series where we reduced the Nepheline content 5% at a time from 30% down to amount here. It is impossible that only 5% Nepheline could produce a body of only 1.5% porosity at cone 10, but here it is! The only explanation is that VeeGum is the most powerful body flux ever. It is also impossible that a body this high in silica can be fired down through quartz inversion without cracking. But it can!
Reaction has been exceptionally good, people are ecstatic about its performance and firing. The body is intentionally not completely vitreous. This provides stability in the kiln. But it also enables the quartz content to impose the highest possible thermal expansion (to prevent glaze crazing). The fired surface is very porcelainous and very white.
Disclaimer: The price of is a reflection of how expensive the materials are and how difficult it is to pug. Notwithstanding that, Plainsman Clays does not have filter-pressing, pre-pugging and stainless-steel pugging equipment (if we did the price would be far higher). Even if we did have such equipment this body would be too sticky to filter-press or pre-pug. This means that there may be some isolated specks. Still, it is far whiter and cleaner than any other high fire porcelain we make.
After a month or two of storage is like a rock in the box. We mean that! It is like a rock. But it softens dramatically when you cut a piece and start to move it. We must pug softer to be able to process it. However it sets in the box on aging. Thorough wedging is a must to loosen it up and remove laminations that can develop over time. Wedge thoroughly to create a homogenous material.
Crystal Ice has extremely high plasticity, you will be able to throw large and very, very thin. BUT, ONLY IF IT IS THE RIGHT STIFFNESS. Do not attempt to use this body if it is too soft (Plainsman must run it too soft to properly pug it). Stiffen it before use to experience its full plasticity. To reduce the water content wedge it and flatten down onto a very clean plaster table or large bat (or you may be able to leave a lump under a cloth over night or longer).
The most prominent side effect of the plasticity is its stickiness, this body is extremely sticky. Studio pugmills cannot likely handle it because of this. It will stick to your hands, to the table, to the cutting wire, anything that touches it. During trimming it will stick back to itself and tools. If you attach ware to the wheelhead with water to trim, it will stick fast there also. After trimming it balls up under your fingers if you attempt to round corners by pressing on them. It is the most sticky when it is too soft. When throwing, water erases the stickiness, it is a joy to work with. And, the stickiness is actually a benefit for one thing: joining pieces, they adhere very well.
If you wish to make this body yourself, weigh the powders and mix them together before adding to the water (the VeeGum must have particles of other materials between its particles or it will not mix with water). Use a powerful mixer so you can use a minimum of water (double the normal amount of water will be needed to get a slurry that will flow). Store it in a large pail (it should gel overnight). When it is gelled you can scoop it onto a thick layer on your plaster table when you need some pugged material. It will take much, much longer to dewater than normal. You will need to peel it up, wedge and lay it back down many times. If you have a big table (e.g. 500 lb) you can make large amounts of the body.
Pictures
Glaze very thick on Crystal Ice Ten
Crystal Ice 5 almost fits L3802D. The one on the left was subject to boil:ice test and some cracks have developed along the edge where it is thickest. The other bowl is still clear of cracks. Slightly more silica is needed in the body. Fired to cone 10 oxidation.
This was subjected to boil:ice test. Neither the thin glaze on the edges or thick on the bottom have crazed (G3808). However, as a result, the bowl has lost its ring (micro cracks). That means that Crystal Ice Ten will not likely be useful for mugs or utilitarian ware that will be subjected to constant thermal shocks. Strangely, on refire that bowl had its right back!
Crystal Ice Ten E closeup
Crystal Ice E (top) vs D (bottom)
Fired to cone 10
Crystal Ice Ten fired vase
8 inch vase weighs only 630 grams.
I breaks cleanly along a line made with a hammer. Fired strength is not as high as P700.
Dried bowl, vase Crystal Ice
These were stiffened under a fan, trimmed and then allow to dry without covering. The vase is 18" high (dry) and the bowl 12". The vase was thrown in two pieces and joined, there are no hairline cracks.
Crystal Ice 3802 bars
The series of 6 development versions cone 10R left and 10 oxidation (right). Higher nepheline versions bloated badly in oxidation.
L3802E Crystal Ice Ten fired bars
Fired at cone 10. These show the reductions in Nepheline Syenite. All of these are too vitreous and unstable in the kiln (except for the bottom one).
