Going Local: How to Dig and Process Your Own Clay

Graham Sheehan pours some local clay through a sieve.

There is an abundance of clay in my area, and I have occasionally thought about making work out of local clay, but the process seemed intimidating, so I never actually tried it (or maybe it was just pure laziness!). But as Graham Sheehan demonstrates in this video clip, the process is not all that difficult. It might not be practical for everyone, but if you’re willing to do a little bit of manual labor, digging your own clay can be a great way to create an even closer connection to the work you make, and help lessen your carbon footprint in the process. – Jennifer Poellot Harnetty, editor.



**First published in May 2010
Comments
  • Michael K.

    This looks familiar! I dig my clay, here in NC. I get a lot of satisfaction from using clay from my field, but find that the process far from economical. Yet if I blend my red dirt with fire clay and local spar it begins to make the ends begin to justify the means. Here is a link to some pictures of my process.

  • Thank you for this informative video. I recently discovered that a favourite river mud that makes wonderful terracotta type flower pots also makes a beautiful cone 10 glaze!

  • This was a great video. I have never dug clay before and this was very informative. Now I know what the process is and how to do it.

  • Nancy S.

    When I saw that this was featured, I wasn’t going to even watch it because I use commercial clay. But I’m really glad to see this. It makes me really appreciate what goes in to making 25 lbs.of clay. Thanks

  • Jack W.

    Hi Guys:

    Lets think an engineering thought or two. There is no reason to dry the clay and then rewet it before screening. Add just enough water to the freshly dug clay to make a pourable slurry, and then screen the slurry. You may want to add a third coarser screen on top to stop the sticks and stones but that should be no problem. This shortcut will eliminate much time, trouble, and unnecessary exposure to dust Addition of a small amount of flocculant chemical to the slurry may also speed up dewatering on the fabric filter.

    We probably should also mention that high fire clay is kaolin but most clays we are likely to find are not kaolin and they will only be useful for low fire applications. That will save a lot of energy during firing and there are hundreds of low fire glazes on the market so much should be possible along these lines.

  • Keith M.

    Hey Jack,

    Let’s not overlook the fact that he told us in the video that most dug clays will be low fire clays and not Kaolin (and not all high fire clays are kaolin).
    And I can assure you that already saturated clay would take longer to absorb any excess water to make a slurry than if you dried it first… which is why it was suggested in the video. Although, I would suggest wearing a respirator over a small disposable mask like the one he wore. It’s not “engineering”, it’s just common sense and real basic science.

  • Miryom R.

    I always have trouble when trying to see a video. any suggestions?

  • Janice D.

    You can put dry chunks of clay between plywood and drive a car on it to pulverize it. If you let the clay dry on racks in fabric you avoid the inconsistancy of texture of the air and plaster method. Before you do any of this it might be an idea to test a bit of this clay in a bisque bowl starting at a very low fire and working up. If it melts at a low temperature it may only be good for glaze. My local clay makes a beautiful cone 9 glaze with a small addition of wood ash…. but I doubt it would ever be good for making pots because of small shell bits.

  • Hi Jack & Keith
    both of you are right in some extent. it’s actually depends on user choice.the end result will be same in either case. In Jack’s method if you use a mixture then all the problem will be solved which mentioned by Keith.
    Three thanks to Graham for nice vedio demonstration…

  • Jack W.

    Hi Keith:

    I guess the engineering part is that dewatering and drying are expensive operations at any significant scale so double drying would be unacceptable. I have heard for so long that drying and resoaking is the way to make up workable clay from partly dried clay, but dug clay may be somewhat different in many cases. Seems to me that we should be able to apply the old oil paint mixing technique, where we pour off the oil, get the bottom sediment into mixable condition and then add the oil back a little at a time mixing all the while. We should in many cases be able to do the same with the dug clay using one of the stronger glaze or paint mixers in a drill motor, adding water a little at a time. A little presoaking time in the bucket may also be helpful. This method would also have the advantage that we could pour the clay out of the bucket rather than dig it out. Being older and less energetic I look for the easier way. The drying-crushing-soaking method was devised to deal with large lumps of partly dried clay, whole bags of leather hard clay for example. By the way if your bag of clay is too hard to be workable but soft enough to be penetrated by a stick or piece of rebar, you can poke a number of holes almost all the way through the clay, fill the holes with water and let the closed bag soak for a week or two.,The clay will soften to workable texture, but the holes must be wedged out before use.

    Our clay here is kind of OK for terra cotta but is too high in iron for a decent cone 10 glaze unless mixed half and half with feldspar.

    I am so pleased that people take the time to produce these videos, keep up the good work all.

    JW

  • Janet T.

    Hm—we live in Pahrump,NV, alkaline desert, on top of an ancient lakebed(I think) and seeing mucho cracks all over the ground, makes me think I’m living ON TOP of my clay source. Been thinking about testing it, but procrastinating with other avenues of art results in no knowlege about what clay I got under my feet!!! Yes, it takes muscle and INTENT. Start, Janet— OK.

  • Christine P.

    Cookie… I downloaded Firefox and use that for my internet now instead of Explorer. I find the videos work much better with this system.
    Other than that, try the following: click the ‘play’ arrow and walk away. Then after 15 mins or so, come back and it should be done. Click ‘play’ again and it might play the video for you. This worked for me with Explorer.

  • Sandra T.

    I live on Lesvos Island in Greece where I have been digging, processing, and testing various local clays for about a year. It is very satisfying to know the land on such intimate terms and well worth the effort. I do this because I want my work to reflect the local landscape with all of its character and ambiguities.

    The traditional way of processing clay here on the island is to dry it before slaking. I have tried slaking and blunging the clay as dug but have found that by drying and pulverizing it first, the clay absorbs water much more readily and the resulting body has far greater plasticity. I make a yogurty slurry that passes fairly easily through the screens.

    Thanks for the great video. Graham Sheehan is one of my heroes.

  • Bimal V.

    I am a starter in pottery. I wanted to know what other chemicals we can add into dug clay to make it more better. At least i wanted to know the standard stuff which i can use to do the mixing like Feldpsar Kaolin etc.

    Would appreciate any comments

    Thanks,
    Bimal

  • Pete G.

    I use a series of large home-made plaster discs to stiffen my slurry, stacking up alternate layers of slurry and discs like a huge “Dagwood sandwich”. These are 1 1/2″ thick. I try to avoid getting chips of plaster mixed into the clay, as these will cause “pop-outs” later.

    This method takes only a couple of hours, depending on whether the discs were dry or damp beforehand. The layers of clay are usually 1″ to 1 1/2″ in thickness, depending on initial consistency of the slurry…the thinner these layers, the less time is required, and the lower the yield. Dry the discs in the sun afterward, and they’re ready to use again.

  • Michael S.

    great video! it would be nice to see the pieces being made and the final results from this clay.

  • Andrew C.

    Nice work, I love the whole idea of making from start to finish ,seems in life now its just too easy to pick stuff of the shelf.
    I am a mature student in Northern Ireland and after reading Dennis parks book on once fireing with him finding his own clay,I have been digging some from the local river ,just have to build the waste oil klin to fire it.

  • Rebecca M.

    I’ve been wanting to try this for years, since school years when I one day saw the professor mixing clay bodies, and the boxes he was opening were return addressed to the (I thought, limestone) quarry that was a quarter of a mile from my family farm! I just moved back to the area . . . experiments are gonna happen!

  • Great how to video, told me everything I need to know. I’ll be sure to head to the river behind my school next semester and try this out! Thanks!!!

  • Martha J.

    Very useful video. I’d like to add that before I left Japan (after 15 years there) my sensei gave me 20 kilos of what looked like dirt from the garden and challenged me to use it all. Leaving the impurities in made for an interesting throwing experience but created the most beautiful craters, bursts and textures in the wood-fired ware.

  • Cheryl A.

    Hi

    Does anyone have any experience with getting permission to dig clay on property you don’t own?

    I live in a suburban area–with a pretty small lawn. I’m pretty certain my husband wouldn’t go for me digging up the lawn to mine clay. And the housing association might decide they needed to make a rule if I dug more than a few pound of clay out of my back yard…

    I think there is probably lots of clay around here, but I wouldn’t want to get arrested or fined (*that* could get expensive) for digging it up and carrying it off for my own personal use. Especially if it were for commercial use — e.g. I planned to sell the pottery. Normally it isn’t legal to just go around mining stuff without first obtaining mining rights or other kinds of permissions from the landowners, including publicly owned property.

    I’m thinking I probably need to just continue buying commercially made clay. Or I would need to buy an unregulated patch of land way out in the country, if I wanted to use the dig-it-myself system.

    –Cheryl

  • Andrea L.

    Could a pugger have alleviated some of the work here? and how?
    I’m thinking of buying a pugger and I’m looking for more excuses to do so….

    Andréa

  • Brenda W.

    Cheryl’s remark made me think of all the clay deposits outside my studio door (ZIP 19510)

    I’ve dug and processed and fired samples; it’s low fired Oley Valley Earthenware.

    Anyone in the area is welcome to come “Dig Your Own”.

  • 3 years ago, prior to pottery, I had 8 tons of clay delivered to my home for a bocce ball court I was building. Not that I am going to tear up the court now, but I know where to get well over 200 tons of this stuff: our local quarry has an enormous hole they drive their heavy equipment in, and the bottom is nothing but this pure clay which they love do give away for free. If you have a quarry nearby, you may want to check it out as they have no use for the stuff. What someone could explain to me is how do you know what kind of clay you have and what it can fire to properly?

  • Jack W.

    High Dave:

    The Orton Foundation makes a pyrometric cone mold that will allow you to make up your own pyrometric cones from your clays and fire your unknown clays along with Orton cones to determine your proper firing temperatures. The Orton Foundation people should be able to guide you in this direction, try Google search. One clay miner would use an acetylene torch to make a fused bead in a line across his clay layers to get some idea of the firing color of the clay, before mining. I have not done this but I assume that you could do a similar fusion test with small pieces of your dried unknown clays and compare them to known commercial clay too. Wear safety glasses though for obvious reasons.

    There is an enormous amount of information out there on soils and clays that should be very helpful in locating clay deposits of various kinds. State geological departments will have such information as may the geology departments at universities and also the soils departments at universities. The federal soil conservation service may also be a good source. In our area the soils have been mapped for agricultural purposes and that may be true almost everywhere. Such maps should be available at your local agricultural extension offices. Furthermore the types of clays may have been determined with fair accuracy so you may be able to find kaolin (for example) in some places from which you can make high fire bodies. The person in Pharump Nevada may find that the cracked clay underfoot is swelling bentonite that will be impossible to make pots from. Of course the simple test for plasticity shown in the video is very quick and valuable in that it ignores all the fine points and leads to the identification of workable plastic bodies. You can use all of the above to advantage.

    JW

  • Ludy R.

    i began experimenting pottery by my own before getting to know this website. i quitted my job and began to do some pottery work. The task is so daunting, i don’t know where to start, but because of the information i got from this wonderful and helpful ideas from all over those who have great experiences, i began to learn and apply such information.
    Thank you for the free pottery information.

  • I live in a county in Illinois where the topsoil barely covers the extensive layer of clay! Makes gardening a real chore! But the clay is a beautiful ^6 glaze (cleaned) straight out of the ground! Remember that “found” clay can be used as a glaze as well! Be sure to test-fire your dug clay inside another bisque pot to avoid kiln meltdown disasters!

  • Thanks for the tip Patty. I just dug clay from our family ranch and can’t wait to test it. It was dry from an old creek bank. I soaked it and then screened it through a piece of screen door fabric a few times being impatient to see what I had. With this particular clay it worked beautifully in a very short time. Then I kept pouring off the water and now have beautiful clay to experiment with. I would have not thought to place the test clay in another bisque pot…thanks! While I don’t picture myself using this clay as my main source I think with experimentation it could be a great addition or glaze.

  • Stephanie M.

    My husband and I have been experimenting with bucketloads of ‘dirt’ from around our place and have fired a few kiln loads with our local clay now. We have had light orange all the way to black – it all fires to a deep red. Too much hard work to get enough to make large pots, but absolutely perfect to make beads and pendants. I like the double screen idea and will include that in our process. thanks!

  • June M.

    Found this video and comments most information. I just recently purchased a potters wheel and kiln and can hardly wait to begin cermanics once again, after time away. Living in Oregon where the local earth is so dense and cracks profoundly in the summer months I have been interested in the idea of local clay. This is most motivation, to secure mud after our Coquille River subsides.

  • Miguel C.

    Hello fellows Artist, I must say that this is very helpful and I love this Webb, The videos, thank you .

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