Introduction: DIY Primitive Pottery Firing

Today, ceramics are all around you. The bowls and plates that food is served on, the inside of electronics that I am typing with and you are reading on, and toilets where the contents of those bowls and plates are returned. But have you ever thought of where they came from? Most of the ceramic you own was probably made automatically by machines and fired in electric or gas kilns, but these are very recent innovations that have only been around for a couple hundred years or so. Humanity has been making pottery for tens of thousands of years by using simple wood fires, and today, I will be showing you how to do just that.

Step 1: Dig a Hole

Pretty much as simple as it sounds. You can skip this part all together and just fire your clay in a fire pit like how it was done for a very long time, but a pit kiln like this has many advantages. First of all, the temperatures are much more stable, meaning there is a lower chance of your pottery breaking during the firing process, the walls act as insulation, meaning a higher potential temperature, and you will have more control over things like wind and fuel. The shape of the hole isn't to critical, but the more spread out, the more heat you will lose to the ground. Dig it deep enough for all of the fuel to fit in, but not too deep or there won't be enough oxygen getting in to burn the fuel. My hole is about 1 foot deep (a third of a meter), but you will probably want to go deeper with larger firings. I also added a cinder block to the bottom to provide extra insulation. Ideally, this would be done on all sides with rocks, cement or clay, but you can still get sufficient temperatures without.

Step 2: Insert Greenware

Take your pieces and place them in the hole. Not much to this one, but you will need to consider logs falling as they burn, distribution of the coals, and if they break, damaging adjacent pieces. You can use most standard clay used by hobbyists (except for polymer clays). They are typically stoneware or porcelain, but I think it is more fun and rewarding to go out to a river bank and find your own clay. It will probably break a lot more than commercial clays, but the result will be unique and something you can be proud of knowing exactly where and how it got to be.

Step 3: Adding Fuel

This will basically be built like any other camp fire, the only difference is it is built in a hole, so make sure there is a path for air to get to the underside of the logs. Any kind of wood can be used really, as long as it is dry. The only thing that is really important to this process is the coals; they fall down and make direct contact with the greenware. The coals will need to cover the pottery entirely, keep adding wood until you achieve this. You might want to completely fill the space around, under and on top of the pieces with stuff like straw, dried leaves, or wood shavings. This layer will burn and deplete the oxygen, creating a reducing atmosphere, making the pottery turn a nice black color. You can even try to add chemicals to the fire like copper sulfate or even salt to add flashes of color to your pieces.

Step 4: Cooling

This part requires no labor whatsoever, the hard part is being patient; do not tamper with anything! Even without touching anything, there is a high chance of failure for wood firings. Cooling is the part where most breakage happens. As they cool, they will contract. If one part cools faster, it will of course contract faster, and cause a fracture. These fractures might be violent enough to shoot fragments off that will break other pieces. Depending on the size of the firing, cooling might take from a couple hours to well over 12 hours or longer. Don't be tempted to take the pieces out until they are almost completely cooled down.

Step 5: The Result

If you are lucky, your pieces will all turn out okay, but if there is a high percentage of breakage, it might be because of either your fire, your clay, or just bad luck. Many of my pieces had minor cracks, but were still functional. I would say this was largely successful! Try this yourself, find something that works, and experiment further. Good luck!

Want to know how I found my own clay in nature? Click here!

Comments

author
Man+Up made it!(author)2016-04-20

If you're fortunate to live along (or near) the fall line in Georgia, you will find that the native red clay soil often has veins of white clay in it. That clay is called "kaolinite". When fired properly (heck, if even poorly fired), it makes a fantastically durable liner for high temperature ovens. You can also order it as "refractory clay" and mix it in with your native clays. (It can also be eaten; a native use here in Georgia was as an appetite supressant.)

author
pocketknifejeff made it!(author)2017-07-08

Digging in my yard in several places(planting trees, putting in posts,etc) have found white clay a couple of feet down. About a foot thick. Is it safe to assume this is koalinite clay? I live in the saginaw valley of michigan. I am a new to the world of clay and pottery. Would like to make my very own kiln. Any more information on this would be greatly appreciated

author
Man+Up made it!(author)2017-07-09

Bad news - not kaolinite. There are clays heavy in calcium ("calcerous" clays) that have a white appearance, and will fire white. But they do not contain significant levels of aluminasilicate. If fired to too high of a temperature, they will basically crumble.

author
Bigtoothcow made it!(author)2016-04-20

I never heard of the fall line before, it sounds very interesting. Unfortunately, I live in New England, so I probably won't be coming down anytime soon. I would love to find kaolinite to make some crucibles or fire bricks, as stone ware won't work well for that. Also, I want to say kaolinite is also used to purify water too.

author
FlyPot made it!(author)2016-10-07

It's better to pile up a mound of earth above grade and dig a hole in that (keeping the hole above grade also). By digging into the soil - once the fire is lit you can actually set root structures on fire. If you have very dry or rocky soil those roots can continue to burn long after your fire has gone out.

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PZ456 made it!(author)2016-05-18

I don't know much about pottery so have a question. You mentioned greenware in Step 3. What is that? Is it a certain stage of the process?

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Bigtoothcow made it!(author)2016-05-18

Greenware simply refers to an item made out of clay but has not been fired yet.

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TeresaM7 made it!(author)2016-04-19

I remember hosting a class given by a Native American woman who is an artist and who pit fires all of her clay creations - pots, figures, dolls, etc. The class was fascinating! Though she did it differently. She didn't use any wood other than twigs and small pieces. It's been so long ago, I don't remember her exact technique, but I remember filling the pit with her fuel, firing, let it reduce, refill, fire again, and then a third time. After that, it seems she let it smolder for a specific time. She's on my FB friends list, so I'll have to ask her the exact procedure. I should definitely do this, since my lawn is thick, heavy red clay. Thank you for reminding me!

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HerrS made it!(author)2016-04-19

Please do, and report back to us:)

author
TeresaM7 made it!(author)2016-05-18

OK, folks, here you go!
Cher Shaffer

Local clay needs to be dried, and then screened to take out the little particles of stone. Reconstitute the clay with water. Pour water in a bucket over the dried clay, and put a lid on it, overnight. If the clay will make a nice ball, and is not too stickey to work into a shape, or crumbly and will not hols a shape, it is ready to work. Make sure finished pieces are completely dry. Check this by holding dry pieces to your cheek. If they feel cool, they still need to dry more. If they are ready to fire.

Build the fire in a pit , burn the fire until it is embers, (my note: when we did this in class, I remember doing this three times before we put in the rack and clay items below - fill the pit, burn it off, and repeat two more times. This gets the earth good and hot) and then place a wire rack over the embers. You then place your dried pots on the rack. Cover with dried grass, hay, or leaves, that are slightly dampish. This creates the famous yellow smoke, and you want to keep the smoking going for about 2 to 3 hours. If the fire starts to flame, put more dampish materials on it, and continue to distinguish any flames this way. I usually let the fire cool overnight, and uncover the clay objects the next morning. Be careful, the clay will still be hot, and it needs time to cool, so do not get hasty in uncovering, and taking the objects out to soon. The clay objects should be a nice carbonized black color from the smoke. They are still not water tight, so do not put water, or liquid in them.

8:49am
Teresa McCoy

What is the ratio of clay to sand? I remember crushing sandstone and mixing it into the clay. (My note: I remember collecting some of that bluish stone from around the creek, the kind that has little flecks in it from mica or some such mineral, though I see no reason why you couldn't use any sand, though I'd make sure it's good quality).

Cher Shaffer

Mix in a little sand at a times,squeezing to make sure the clay,water,sand mix will still make a ball that holds together

Teresa McCoy

So it's an "instinct" thing rather than actual percentages. No surprises there! I will experiment when I have some time. Thank you so much! When I'm able to give this a try, I'll send you photos so you can see how your instructions have worked.

author
Bigtoothcow made it!(author)2016-04-19

Interesting, like multiple successive firings? I remember from my high school art class watching a video of native American pottery in the great plains. They used dried cow patties and grass instead of wood because of its scarcity.

author
TeresaM7 made it!(author)2016-04-19

It's been so long ago, I'm not sure. If I recall correctly, she burned everything down in her pit twice. This was to heat the outer area. Then she added the items, piled the final burn material on top and let it burn again, then let it sit. I'll definitely share anything she tells me :)

author
Rackskop made it!(author)2016-04-19

Would be great if you asked her and shared those slight differences with us so we can experiment with each technique. Kudos!

author
bricobart made it!(author)2016-04-27

Just love it, that result! Reminds me also I need to fire the rest of the stuff I made last year ;)

author
ZombieWorkshop made it!(author)2016-04-19

I join all the other user saying amazing work and please make the second part how to make the clay for the pottery , excellent job

author
ZombieWorkshop made it!(author)2016-04-23

Checking right now, thanks

author
Lsutiger51 made it!(author)2016-04-14

Could make an instructable on how to make the pottery before the firing?

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Bigtoothcow made it!(author)2016-04-14

Yes, I was planning on such. I was also thinking about finding and procrssing local clay. I might even do a primitive glaze.

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swimspud made it!(author)2016-04-19

local clay tutorial or something like a Terra Cotta would be epic. I'd like to make a bunch of pots for plants outside. And this seems so fun!

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Bigtoothcow made it!(author)2016-04-19

I'm actually working on this right now!

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RockeyDA made it!(author)2016-04-19

this is just plain awsome and if i ever get off time at work im would love to try it when im camping out in the mountains.

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Bigtoothcow made it!(author)2016-04-20

Glad you liked it! The entire process will probably take a few days though. The actual firing (as long as its small like this one) will take maybe 5 or 6 hours, but waiting for your greenware to dry will take a while. And if you need to process the clay, probably a bit longer.

author
VajkF made it!(author)2016-04-14

There is a similar technic: somewhat bigger hole, wood shawings from a planer/jointer below, in and around and on top of the pieces. then make a fire on top. when ignited, cover almost entirely just leave a small area for air. burns slowly for a day or more.

author
Bigtoothcow made it!(author)2016-04-14

I actually tried something similar to that already. Before firing, you can see one of the bowls is black, that is because it already went through a firing similar to the one you are describing, but failed. I think it might have been to small, or the dimensions weren't right. Thanks for the comment though, I will have to try it again sometime!

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spark+master made it!(author)2016-04-19

black color is due to lack of O2 at cool down.

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Bigtoothcow made it!(author)2016-04-19

Yep, using wood shavings, leaves, straw, et cetera quickly depletes the oxygen. Since it can't burn, it pyrolyzes and deposits free carbon onto what ever is nearby. In the future, I want to take advantage of this and use plants that contain high amounts of a certain salt to color my pieces.

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VajkF made it!(author)2016-04-14

https://www.youtube.com/watch?v=OZtWewsZAsI

I remembered this one.

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Bigtoothcow made it!(author)2016-04-14

Oh yes, I've seen this one. Very neat process. Perhaps I will make another Instructable with something similar.

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Next+Gen+Ideas made it!(author)2016-04-19

Your name is really inspiring to me, I might do something with that and it will be a next gen idea I can assure you.

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1joyjunkie2 made it!(author)2016-04-18

Gosh, this is wonderful! I had one of those $1400 kilns that I practically had to give away due to a move. This will work perfectly. Thank you! Weehooo!

author
Bigtoothcow made it!(author)2016-04-18

Well, I am very glad you enjoyed it! However, this really isn't the best way to fire pottery, especially for utilitarian purposes. If you are interested solely in the ceramics, an actual kiln is the way to go. There is a few instructables to make your own little electric kilns which are cheaper and very neat! But, if you are interested in the process of creating something completely from scratch and don't mind getting a little (very) dirty, try this out! Even if you aren't, see how this method works out for you. There is a lot to learn about the nature of ceramics when you are there for every part of the process, so I recommend doing this at least once. Good luck with your pottery!

author
Ultra-Indigo made it!(author)2016-04-15

I was just talking to my kids about this thanks for the pics, so I can show them what I ment. most of the YouTube shows slaking the clay, screening, filtering, and drying but I could not find primitive firing thanks

author
Bigtoothcow made it!(author)2016-04-15

No problem! Just don't forget there is so many different ways to approach this, and this is only one of countless methods with hundreds of potential variables. This is certainly not a definitive guide, just a barebones method. If you are going to try this yourself, experiment a bit and find what works for you with your set of variables. If you find something that works better, maybe you should make an instructables on it :)

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pastormick made it!(author)2016-04-14

So cool!

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Bigtoothcow made it!(author)2016-04-14

Thanks!

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JasonE4 made it!(author)2016-04-11

nice job, I have done this too. I also like to incoperate natural material into the burn such as grass clippings to see what type of surface coloration I can get.

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CharleeB1 made it!(author)2016-04-11

Great job! If you try the animal fat idea that was suggested, please keep us posted on the results.

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discostu956 made it!(author)2016-04-10

Very nice to know, thanks for sharing. Fired this way, are they any less robust/resilient than fired in a proper kiln? With the clay you collect yourself, does it matter if there is much in the way of sand and other gunk in there?

author
Bigtoothcow made it!(author)2016-04-11

Glad you enjoyed it! This technique achieves lower temperatures than a standard kiln, so I would say things will generally be weaker, not to mention the small cracks that have developed on some of my pieces. If you are collecting clay, you absolutely do need to clean it. Sand isn't too big if a deal (It will mostly just make the clay less pliable), but any and all organic matter must be removed or it will destroy the pottery while firing. I was lucky to find my clay so pure that I could pretty much do every thing by hand, but you could probably add water to the clay until it is a slurry and filter it through a bed sheet if you find clay with a lot of debris in it.

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discostu956 made it!(author)2016-04-11

Thanks. Keen to give it a go eventually

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jmwells made it!(author)2016-04-10

Adding animal fat to the layer above the greenware will make a small amount of lye. This glazes the clay and colors it a bit.

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Bigtoothcow made it!(author)2016-04-11

Interesting, I never heard of this. I will have to try it out next time I do a firing!

author
DIY+Hacks+and+How+Tos made it!(author)2016-04-10

Interesting technique. I might have to try this with my kids.

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Bio: I have always been interested in all kinds of technology, from stone knapping, to nuclear fusion. For most of my childhood, I gathered all sorts ... More »
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