douglas

Just curious, how could they know what glaze they wanted, when they have not seen what it looks like on the stoneware clay? Assuming they picked a test tile, why not use the same clay used on the test tile? It is unlikely to look the same on a stoneware body.

I use a cone six red clay and it comes right off. However when I use it in cone 10 that sometimes happens. I think your clay may be over firing if the alumina gets embedded in the clay. I still use it in cone 10 but I know I will have more clean up and finishing later when I do.

Pour the slip in with your saved trimmings and slop and reclaim the clay.

I second the plaster wetbox advice if you have the space to store the pieces. Mist them and forget them for a few days, and concentrate on making new pots. Pull some handles and store them with the cups. They will stay perfect consistency until you are ready to connect them, and the handles will match the moisture content of the cups. Getting the right amount of water in the plaster may take some fiddling at first, if things are staying too dry pour more water onto the plaster in small amounts.

You don't want to go that slow, since it can lead to drips and runs. Instead do a smooth line, and then go over the same spot once the surface dries. 2-3 coats should be thick enough for most colors. Black or dark colors may only need one coat.

I was going to say the same thing -- get a degree from your current college and start researching MFA programs. Most undergrad programs assume no prior knowledge of clay working, and probably won't challenge you enough.

If you have a pottery supplier that rents kiln space, or a community studio, or a community college you can take classes at, you can get access to a kiln. Buy bisque tiles, by commercial glazes, and paint your designs using glaze. When they are fired the colors will be formed in a glass coating and will resist the elements for years.

Most waxes ignite around 200-250F. Using a heat gun might work better than a hair dryer.

My bet is that you are putting the tiles on hot brick, and the thermal shock is what is cracking them during firing. Try using cold brick to rest the tile on and see if that helps.

One other possible cause is too much glaze or using a runny glaze on the inside of the pot. Maybe when you are pouring the glaze out it is taking a while and the inside has a thicker than normal application? If the glaze is too thick at the bottom of the pot, and if the glaze doesn't shrink at the same rate as your clay body during firing, the thick glaze pooled at the foot is creating a stress crack and the sudden temperature change is causing it to fracture along the spot where the thick glaze ends and the clay wall begins.

Plastic bats seem to cause more cracking than plaster or masonite bats. If I have to use plastic, I wire it off immediately after throwing, and flip it onto it's rim when the rim is strong enough to support itself. If the base is too soft to flip and will sag, then I transfer the plate to a board with newspaper so the base can move easier as it dries and contracts. With plaster or masonite bats, I think they wick away enough moisture from the bottom of the plate to avoid the stress from uneven drying on the rim and the foot, and I don't have to be as careful.

If nothing comes out when you flip the mold over, then you might not be filling the mold up completely. If the walls are hollow that would explain why you are getting two halves instead of a solid bowl. You need to screen or thoroughly mix the slip to remove the lumps. You may also need more water in your slip if it is not able to run all the way into the mold before it dries at the base, blocking you from adding enough slip to fill the mold.

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If you have access to a ball mill, try running the glaze through that before using - that might break up the particle clumps.

Glaze fit means the glaze shrinks at a rate close enough to the clay body shrinkage, that it will not crack or shiver off the clay. Just because your glaze and clay are firing to the same cone, does not mean the glaze will fit the clay. Apologies if you know this, but it seemed like you are equating firing temperatures with whether the glaze should fit in your descriptions. The root of the problem you are experiencing is you are buying off-the-shelf products. Since you don't control the ingredients you don't have control over whether they play well together in the kiln. Learning glaze chemistry is an option, mixing your own, and adjusting to fit your clay body, but that takes most people a lot of time to work out. If you want to be able to just buy glazes and clay, then you should ask your vendors to recommend clay bodies or families of glazes that should work well. If your glaze vendor's response to using earthenware was don't use earthenware, then you either need to follow their advice and choose a different clay body, or keep your clay body and find a different glaze.