Making Clay from Dirt
Hello again folks!
I hope you are all doing well! I am still in quarantine until the end of April, so I have found myself with a lot of free time on my hands. I would tell you I have been getting a lot of writing done, but that isn’t really true. Getting a little done around the house, but not much to tell beyond that.
Which I why I wanted to start posting about practical skills. It gives me something to write about, and I get to share with you all things I have learned over the year. It’s a way for me to teach and share, without having to leave the house. It also keeps me busy, and keeps me from going stir crazy.
Before we jump into the deep end here, I wanted to say that I do this writing free of charge. I don’t want to put this kind of writing behind a paywall or a Patreon. Much of this I learned free on the internet, and then experimented with it, and I want to offer it to you the same way. That being said, this kind of work is… well.. work. It takes a fair bit of labor to type this all out for you. So, if you want to donate $5 or whatever to help support me, my Paypal is here. Again, not required, but donations are appreciated!
About Clay and Soil
Now, for a little bit of background. Soil varies a lot, and can come with all kinds of different compositions, textures, and mineral content. The soil outside your door may be very different than mine, and it helps to have a familiarity with that. You may have a clay rich soil, and this could be an easy process. Or you can have real sandy soil like mine, and so for every bit of clay you produce, you are guaranteed to have more sand than you know what to do with…
Without going into too much detail (I’m trying to keep this short, so I may expand on this in another post), clays are the result of mineral weathering, when certain rocks and minerals break down and leach into the soil. One of the chief producers of clay is water. Specifically, low energy water. (Low energy deposition is the technical term.) Think slow moving rivers, lakes, and especially wetlands. Some of the best clay I have ever dug came from a swamp! So if you have a river or a lake nearby, those will probably yield the best clays. But you may be able to get it out of your backyard as well!
Faster waters tend to flush clay minerals downstream, and into river deltas and things like that. Clay has been easier for me to find in low energy water bodies, and so the clays are all deposited on site, in river banks and such.
Clay is formed when water breaks apart rocks, minerals, and soil; and separates out the clay minerals. This are tiny particles that are smaller than gravel, sand, or even silt. It’s the very fine nature of the clay minerals that gives clay their distinct plasticity. That is why our ancestors learned to cast, shape, and mold clay into all kinds of cermamics and pottery!
A Little Animism
Again, without going too much in depth, as a practicing animist, it goes without saying that working with the earth and with clay has a deep spiritual component for me. The Earth is the planet from which all life we know shares a common heritage and ancestry. Digging into the soil is creating a close relationship with the Earth, and deepening that connection. As a former archaeology student, the land beneath our feet is in a very real the living memory of the Earth, the layers of geology and human prehistory are like memories of the planet. More than this, clays and ceramics are one of the oldest materials that our ancestors learned, and for me the process is a deep way of connecting with them as well. This could also be a whole other article in itself, but I wanted to briefly touch on it.
Alright, let’s begin! One of the best parts of digging clay is that is pretty straightforward, and doesn’t have a lot of material needed;
- Approximately 3 – 5 gallon buckets. (I tend to use about three buckets, but the number varies based on how much you dig.)
- A shovel. Preferably one with a long handle, for your back and because the hole you dig may get deep.
- Water. You’ll need water, and a fair bit of it. I use a hose at the back of my house. You can also use an extra bucket or two filled with water.
- A fine screen. Something with about 1/8 inch holes or so. I literally just have a roll of fine-ish metal mesh from Home Depot. This is for sifting out organic material, rocks, and other debris.
- A stick. For stirring up mud in a bucket. I use an old shovel handle.
- 2 or 3 pillow cases. Cheap ones from like Big Lots, or old ones. Nothing too fancy. They will be filled with mud.
Step 1 – Dig Dirt
Now it’s time to dig some dirt. You notice I’ve included a picture for this section. This is a soil horizon, and this is important context for HOW to dig dirt for clay. You don’t really want the first two layers (O & A “topsoil” layers) , as you don’t want all the organic stuff, and at least in my soil, there isn’t much clay in these layers. What you typically want is the B layer, the subsoil. As clay minerals weather, they move down deeper into the soil. The B layer is sometimes called the “banking” layer, because it stores a lot of minerals that can be “withdrawn” later by the plants above. But we are interested in the clay in this layer, so this is what you want to dig. In my own soil, this is a really sandy layer, and pretty easy to dig through. Your mileage may vary.
To start out with, I typically will fill one of my 5 gallon buckets about half way with dirt. You need room for water, afterall. So now, you have a bucket of dirt! Hurray!
(Alright, I have two…)
Step 2 – Make Dirt Slurry
Now that you have your bucket of dirt, it is now time to make a mud shake. Carry your dirt to wherever your water supply is (outside preferably, your housemates will thank you). You want to pour water on top of your dirt, and generally you want more water than dirt. Take your stick and stir it all up! Make yourself a runny mud-shake… The boys won’t show up in your yard for this one. Probably.
The idea here is to completely liquefy your dirt sample. The reason why will become apparent in our next step.
Soup is ready! (Do not eat.)
Step 3 – Screen and Filter
The reason we wanted to make a mud slurry is because it will separate your dirt into all it’s various components. Clay will suspend into the water, organic debris will float, and sand and rocks will sink to the bottom. Now we have to do the work of separating it all out.
This part can get heavy, so heads up. Don’t hurt yourself alright, as buckets of water and dirty aren’t light. Lay your screen/mesh over top of an empty bucket, near to where you made your slurry. Stir it up real good the first time, and then strain the bucket of slurry through the screen and into the empty bucket underneath. The screen will catch a lot of organics, rocks, and even some of the sand. Once you’ve strained it, take the screen somewhere and shake it off, and maybe give it a good rinse.
(Bucket with screen.)
In my experience, you will probably do this step a couple of times. Stir, strain, repeat. If you are using the same bucket over again, be sure to rinse it out before you strain the slurry back into it. Otherwise you’re just putting it back in.
While you are straining, you may notice that the sand settles to the bottom. Getting that out is our next step. The straining will get some of it out, but not all of it. Here, we take advantage of the fact that sand sinks. Stir up your freshly strained slurry, and let it sit a couple of minutes this time. Now pour it back into a clean empty bucket, slowly. The sand will be stuck at the bottom, so don’t pour that into your clean bucket. Dump the sand out, and do it again. Rinse, and repeat as needed, until all you have is mostly clay suspended in water. Again, you may have to do this a few times to get all the sand out.
Typically, I will strain at least twice, and separate the sand out at least twice. As I said before, this can get heavy, so take your time and save your back! If you need to take a break, do so. Stuff may settle, but you can always stir it back up if it settles too much.
(Screening out debris, and leaving behind the sand.)
Step 4 – Pour into Pillow Cases, and hang to dry
When you are all done, you should have a bucket of mostly dirty water. No rocks, debris, or sand should be evident. Depending on the clay content of your soil, this could be a thicker or thinner slurry. Either way, the density isn’t a big deal right now. What matters is you have some amount of clay suspended in water, and free of stuff you don’t want. Now, we have to get the clay separated from the water.
Into the bucket with you!
In a clean empty bucket (likely one you already used, and cleaned. It doesn’t have to be dry, just clean), take one of your pillow cases and use it like you would a trash bag. Line the bucket with it, and pull it over the edges. Pour some of your slurry into this pillow case/bucket combo. Some will leak out into the bucket, and that’s okay. The idea here is most of your clay-water is contained in a filtering pillow case. Now, just hang up that pillow case and allow it to drip out the water.
It is okay if you use more than one pillowcase during this process. In fact, it’s best to not dump a bucket full of clay slurry into one case, break it up. It will dry out faster, and you won’t have to hang up one heavy case full of water!
What will happen is that the clay will settle in a corner of the pillow case, and act as a filter for the water. This works better on warmer days, as the water can evaporate too, leaving just the clay behind in a pillow case.
Mud on a line, wasting all my time…
Also, it’s best not to let it completely dry out. (You can, but then you have to crush up the dried clay into powder, and add water again.) Grab the pillowcase on occasion, and you can tell by touch when the clay is ready. This drying period can take a few days depending on temperature. Also, don’t leave it out in the rain, as that defeats the purpose.
Step 5 – Clay!
Ball of clay!
When your pillow case has filtered out most of the water, all you have to do is turn it inside out and extract the ball of the clay inside. Congratulations, you have made clay from soil! Or maybe not, sometimes it takes a little trial and error to get it right. Sometimes you get clay, sometimes you don’t. I’ve gotten sandy balls of kinda-clay, and things that are best just tossed back into the hole. Soils vary a lot in color, minerals, and clay content. While the backyard is a great place to start, I dig soil from all over the place, and each result is a little bit different.
Each clay can be different too. They can vary a lot in color, plasticity, and how the clay responds to later steps such as throwing, casting, and firing. Some clays will cast great, but throw poorly. Some will throw and coil like a dream, but cast like hell on wheels. Some will fire fantastically (to all kinds of temperature ranges), others will blow up dramatically. There is a lot of trial and error to this, so don’t beat yourself up if it doesn’t go right the first time.
Please feel free to ask questions or ask for clarification as needed. This is my first how-to, and again, that trial and error thing. At the end of this post is a short list of additional resources and Youtube videos, so you can go above and beyond what I have explained here. Google is also a fantastic tool!
As always, thanks for reading!
The King of Random – Youtube (This one really helped me get going!)