where can i buy or harvest clay for earthen floor

i live in north-east Oklahoma and i am building a round timber house and want to have earthen floors but i am having trouble finding clay. and honestly i'm not sure what type of clay to use. our local feed store has bag clay (Bentonite) that they use to patch leaking ponds but it has an incredible expansion rate (20 times original size) and i'm afraid that when it dries it will shrink too much. all the places i have looked on line just say
"clay" can't seem to find out where to get and if i have it on my property, is there a way to test it??? thanks for anyone's input. very much appreciated !!

Heidi, don't make this too difficult, just get a shovel and dig some. Where I am, all you have to do is dig down a foot or two, and you will have all the kaolin you will ever need. In your area, places to look are river banks, seasonal ponds that dry out and have clay chips on the surface, stands of magnolia trees (they LOVE to be sitting on top of clay). If there are any old abandoned brick pits, well, now you know where the folks in your area got their clay a hundred years ago.

Here's how to do your own soil test: Get a big glass jar, fill it about a 1/3 full of your soil sample, add the same amount of water, put the lid on and shake it real good. Now go away and let it sit for an hour. When you come back, you will see that it has settled into the sand, silt, and clay fractions. There should be noticeable changes of color between the layers. If the water on top is still muddy looking, that's an indication that you have a lot of clay. By measuring the thickness of each layer with a ruler, you can come up with a pretty accurate analysis as to your soil type. When I do this with a deep sample of my "soil", there are no rocks or sand at the bottom, hardly any silt, and I have a jar full of clay that looks like butterscotch pudding.

You can also use this soil test method, scaled up, to separate the clay from the sand and silt. Just pour the excess water off the top and then you have clay on top that you can use to make pots or tiles with. There are many different types of clay, and bentonite is at one extreme as far as swelling is concerned. You have two choices if you dig your own clay though: (1) scientifically analyze it or (2) do like an artisan and just get your hands dirty and work with it and see how it behaves. Before The Enlightenment, everyone went through the latter choice in learning how to work with their local clay.

When I need clean clay to work with, I let it dry out and pound it in a paint bucket with a 2x4 and sift it through a colander. This gets rid of stray roots and other pieces of organic matter I don't want to incorporate into my final use. Don't be afraid to get dirty, just go out there with your shovel and find out what's under your feet.

john, thank you so much for your info. I'm not afraid at all to get dirty, i'm a country girl. haha. i have a good sized pond, a shovel and a big pickle jar. i will let you know what i find. so excited i'm heading there now!!!

john, i went to my pond and took a sample from the waters edge. already i could tell that it is high in clay but i put it in a jar of water anyway just to separate it and see what it's like . i'm so excited to try a sample of an earth floor. thanks again so much. your awesome.

Another thought....look on Youtube for videos of Mexicans making saltillo tiles or working with terra cotta. "Terra cotta" means "cooked earth" and some gets cooked more than others. Some of the less cooked kind could be what you are looking for. In Mexico, there is still a tradition of doing this by hand, and it runs the whole spectrum from just sun-dried (which doesn't hold up well to weathering) all the way to fired with a nice glaze on it. I'm glad you are enthused about getting out and playing in the mud, err, make that clay.

thanks for the youtube info, found a couple and want to try some different things with the clay i harvest. it will be a good winter project. now that i know i have clay that i can use i am going out today to get more samples and start processing. and yes i very much like working outside and getting dirty. it always makes me feel closer to god. lol

I just wanted to pipe up and say that I'm going to try this when I go home in a few weeks. Something tells me that the soil around Georgetown, CO is not rife with clay(though that would hardly stop me from showing my kids such a neat trick)...but the adobe flats around Cedaredge might be! Normally I play with fiber- dyeing, spinning and knitting it up and my grandparents have been growing some Japanese indigo out there for me this summer. This might give me something to do between waiting for dyepots to cool. Lately, I've had some major cravings for getting back into throwing pots and making bowls/cups to add to my Etsy repertoire. Not to mention my own kitchen. It's gotten so bad I sometimes daydream about breaking the worst offenders in our cupboard. Is there anything you need to add to the sifted clay before trying to shape it or fire it?

Desirea Holton wrote: Is there anything you need to add to the sifted clay before trying to shape it or fire it?

If you are using it for ceramics or cosmetics, no. For building material, like in adobe bricks and cob, you need some fibrous material to add tensile strength, maybe some sand as a bulk filler.

In places where you have big mountains (CO), clay is harder to find than in places where the mountains have mostly eroded away (GA). You have to poke around in the creeks and dry lake beds to find some that has washed down from the mountains. Here the mountains have been washing down for millions of years, so the part of the state below the fall line (roughly a line from Augusta, through Macon, to Columbus) consists of all the clay that was in the Appalachians covered with a bit of topsoil.

Color is another indicator of the quality of the clay. A reddish or adobe color comes from iron minerals in the clay, and while it is OK for terra cotta, for porcelain or fine china, you want pure, white kaolin. By the way, kaolin shouldn't be pronounced kay-oh-lin with three syllables, it's a Chinese loan word and they pronounce it more like 'cow-lin'. It means "high hill", as in "where did you get the clay for this amazing pottery? From that "high hill" over there."

You might try just calling your local sand & gravel company. This might avoid the very hard work of digging a clay pit in your yard,(an open pit is a fall/trip hazard & can collect water for mosquitoes) sometimes they offer already screened clay which will also save your labor, they often will deliver to your site. You could actually have a pile of clay in your yard today with just a few phone calls & some money.

If you do decide to mine the clay yourself on your place, don't look for moist clay in a pond bank, as wet clay is very difficult to dig. You want dry clay (it is easier to mine & sift when powder dry) and summer time is the best time to dig a good amount of it before it rains again. It helps if you choose a place that has some shade for working under. Cover your freshly mined clay with plastic (top & bottom) to avoid moisture getting in it. I sift my dirt thru a 1/4" rabbit wire screen, to get most of the rocks & root out, the dirt I mine in my yard is 50% rock, 20% root, and 30% dirt. Once you get past the topsoil & silt layers to the more consistently clay dirt, dig (yes you will need a pick, & a tiller helps an awful lot, or a backhoe works even better) screen it with the 1/4" rabbit wire screen (I lay my screen over the wheel barrow to catch the refined dirt). I typically sort my rock in various piles according to size for use later, leave the rock uncovered to get washed by the rain. Nearby 2 gal. buckets are a good way to pour the rocks/gravel in and move to various size piles, throw all the roots in one big pile. This is the hardest amount of work, you might call the sand & gravel co. to avoid all the digging, holes, & rock piles in your yard.

Once you have double more dirt sifted & stored than you think you will need, sift all of it again thru a metal window screen placed atop your 1/4" rabbit wire screen. Now what you have is nearly pure clay dirt. You can further refine the clay dirt by mixing it completely with water in a bucket, find an empty bucket and put the window screen over it, pour the liquid dirt thru the screen into the empty bucket. (a square laundry detergent bucket works well, because it has a sturdy handle and because it has a square side, that makes pouring the water off the top easier than a round bucket) Save all that you filtered on top of the screen in one pile (it is good clay with sand and may be useful later) What you have in the bucket is now nearly pure clay slip, give it some time and let the water rise to the top, pour the excess water off. Have a large storage barrel to put all of your clay slip into, until you need it, add various amendments as you think will make the cob strong, don't use roots unless dried & dead, as roots like to grow!

Test bricks, sun dried will show how much shrink cracking you can expect from your clay. That pickle jar test works great to figure out what you have to sift out to get clay.

james beam