Relief Tiles – Cracks, Temperature

More tiles from the last kiln load. These are done in a relief style, with Velvet underglazes painted on and then washed off before the final firing.

And here is one black and white tile. I had a lot of trouble with this clay this time (it’s Standard 181). I dimly remember having problems with it last winter – a lot of warping and even worse, cracking. I lost more than half the white clay tiles I did this load because they cracked.

I think that the clay may be sensitive to drying too quickly. In the winter, my basement is warmer and drier because of the heater. In summer it’s very cool and damp. I did not have these problems with any of the work I did this summer. So…maybe that’s it? I’ll have to see.

Moon over the ocean.

Moon over the ocean.

10 thoughts on “Relief Tiles – Cracks, Temperature

  1. Claudia McGill Post author

    They are on the back, in the original piece of clay that I then build on. Generally they start at one side and extend inward. They don’t usually come all the way through, but sometimes they do.

    They don’t show up in the bisque firing but appear in the final one.

    I try to handle the clay as little as possible, not bend it, etc., and to help it dry slowly, but it still happens. No other clay I’m using is doing this. And the only thing it happens with is tiles. Not objects.

    Do you have any advice? I’m all ears!

  2. julietmacleod

    The only thing I can think of is the drying. I think that this problem is very comment with tiles, but I don’t have any experience of tile making myself. Do you dry them on foam? So that air can get at the bottom. I’ve also heard of people drying tiles on plaster board so that it draws out the moisture evenly rather than from the edges first. Just thoughts… not proven.

  3. Claudia McGill Post author

    I do think it’s the drying. I usually dry them on newspaper (actually when I make them I set them on a piece of dampened newspaper – I’ve learned that because I press on them to adhere the pieces, they can stick to a board, so the newspaper gives them “moveablity”. I think this particular clay is sensitive to drying too fast or being handled too much. I did notice this happen last winter and now that it’s come again, I think I need to “listen to the clay”…

  4. bluerock / debrazone

    Nice stuff! What do you do with your cracked tiles? Can you make a mosaic with them?

  5. Claudia McGill Post author

    If they are really bad I just throw them out. If not too bad I might sell them at a discount or else use them as they are by setting in concrete for garden ornaments or that kind of thing. Just depends on each individual case as to what works best.

  6. sueblackpenart

    Surely a very fine clay will cause problems when dryed to fast, as it causes severy tentions throughout the material. Supplementary coarse particles as sand will stop the tension from traversing the piece at its whole. So each sand corn will act like a stopper. (me mineralogist bad ass showing off)

  7. Claudia McGill Post author

    You are absolutely right. For me it was always a tradeoff between fine and coarser clays – the fine ones allowed more detail and better glazed look – the coarser ones were more reliable but tended to look more rough. There were of course ways to dry them more slowly but clay does what it wants, I have found!

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