Monday, May 16, 2011

Florida Clay Slip

Ever notice if you like something your eye naturally seeks that item out? For instance, if you like chocolate, your eye naturally hones in on chocolate at the grocery or bakery, doesn't it? I like clay, so when I drive around I can't help but notice clay soil. That's just what happened to me recently. I noticed some rich red clay freshly unearthed in my neighborhood and being laid down as a base to a road widening project. Like a choco-holic I just had to have some of this red clay.

Doesn't it help to have the whole neighborhood involved in your pottery? I think so; and in my case it's true. Here's my neighbor, Jerry, the one who rode his golf cart to get me the trash can full of clay from the construction site. He stopped by the next day to find Gary and I preparing a small batch of the clay soil we took from this trash can full he brought to us.

Here's Gary pulverizing clay clods for my test batch. I put a small amount in a paper bag and Gary used a rubber mallet to break up the clods of clay.

Here's the sieve I'm using to sift the clay. I've placed it on the tailgate of Gary's truck parked in our front yard. The perfect location for preparing clay, don't you think?

I don't have a ball mill and I'm not mixing perfect terra sig like Ben Carter does. I guess I'm really making a fine Florida clay slip.

Maybe it's my imagination, but this clay soil seems much finer and more red than the last batch I got from a similar location. The last batch was loose soil, sandier, and more orange in color. This soil is deeper red and is in clods, maybe it's finer clay with more iron in it. Tomorrow I'll give the soil my finger test. I'll take a small amount and rub it between my thumb and index finger and feel the consistency. Here's what the freshly sifted clay looks like.

Here's the sifted clay with water added to it. I stir it up really well and then set the mixture aside to sit undisturbed for 24 hours.

After 12 hours I only have about 1/8 inch of small particles. Not sure if you can see the small color difference at the top of the soil line. The theory here is the water goes to the top, the heaviest clay particles or sand settle to the bottom and the finest clay particles are in the middle, floating on top of the heaviest clay particles.

After another twelve hours, I will siphon off the water and then slowly siphon out the finest clay particles, being careful not to disturb the bottom layer of larger clay particles. I'll brush a little of this fine Florida clay slip onto a test tile in my bisque load. Normally I brush my slip on wet clay, not sure about putting it on a dry piece.

Update: this clay is smooth as silk between my fingers, not gritty at all, and I didn't even strain it. I put some on a few flowers for this bisque load, fired them and the kiln is cooling down right now.

Time will tell about this native Florida clay, but I had to try using it. And there are many more experiments in this kiln load. Please stay tuned, it should be intereting.


  1. What a fun project! Can't wait to see the results :)

  2. Once again, you've drawn me into your project just through your words. The pics help, too. You make me wish I was a potter. You sound like you're having great fun doing something you love. What's better than that? Thank you for sharing your process with us. Is that a pun?

  3. excellent lil batch of testing!! like...

  4. Thanks for the explanation. I was wondering how ordinary clay dirt became something an artist could use. Interesting process.

  5. With all the beautiful GA red clay we have here I'm often tempted to try what you're doing. I'm excited to see your results.

  6. Hi Kathy, thanks, some how I can't resist red clay along side the road.

    Hi Teresa, thanks, glad you are enjoying my journey with me, the pun went over my head.

    Hi Ang, thanks, this stuff is better than the last, hope it works out.

    Hi Patti, thanks, I took that photo so you could see the difference between the sandy soil and the clay.

    Hi Lori, thanks, you should get a little of that GA clay and try it, it isn't that hard and you never know what it might do for your pots.

  7. That's really cool. How do you decide the temps you are going to test fire at? YEARS ago, when I was in high school, I worked at a soils lab- rich clayey type soil does not make for a good place to build your house (though people do!) but what a great exploration for ceramics!
    In response to your comment on my blog-
    there are 2 types of micaceous clay that I am using-
    one is a commercial clay, which is much easier to use/much more plastic, but I have found it to be much more fragile. The second is hand dug from the mountains of northern NM- it is a lot harder to shape, but it is MUCH stronger, even if only bisqued. the difference is the price- $16 bucks (through the college) for 50 lbs for the commercial vs $100 for the hand dug!!
    I'm doing all my "practice pots" w/ the commercial.
    Thanks for stopping by, and for the follow, I shall do the same!

  8. Hi Becky, thanks for the explanation about the micaceous clay. I once went on a pottery tour at the southern tip of the Baja in Mexico way in the mountains and a local potter was working with that clay which fired a pure black but had little chips of shiny mica in it and it was so beautiful and I have always wanted to try it, one of these days.

    As far as the temps I just try it in either the bisque firing range I use for the other stuff or the cone 6 glaze temp I use for all the other stuff, but coming up next I will be doing a few experiments with lusters, gold and other metals and those fire at a lower temperature, I will use thos sparingly because the gold is very expensive, probably just some highlights for some of my flowers. I read and read and do searches to learn all I can about other peoples experiments and then try to make educated guesses. Ha. it's all fun though.


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