How To: LOCAL clay?

[variableenigma]

Wasn't sure where to put this- I figured that it doesn't fit into "Polymer Clay"!

Anyway, I was helping my parents with some landscaping here in southwestern Michigan, and we found a TON of clay.

I would love to be able to use it to create pots (/whatever I want, haha), but I have no idea where to start. How do I refine it? How to I "cook" it? I do not have a kiln, though I'm sure I could gain access to one if necessary..

I am especially interested in how Native Americans may have done this, or how other primitive cultures still do it to this day. Wouldn't it be cool to re-create the clay wares that they really use(d)? Does anyone know where I can find information on Native American groups that live(d) in Michigan?

Anyone have any thoughts on this?

[SpottedFrog]

I'd say go to a local history site for the tribe names then use those a a jumping off point to search for information about them & their grafts.

I know down here in Texas some early clay pits are still quarried, they are 2-300 years old. We have good* clay, the company that quarries clay nearest to us up in the hill country literally sends it all over the world to building product companies. Their operation is huge though.


* good clay is relative, it's horrid if you are trying to grow anything, great for pots & floor tiles.

[kittyfreud]

I'm just going on what I learned from one semester of Ceramics, but I do know some things. The clay you've got is most likely a low-fire clay, since it is probably not pure clay. Don't take that as an insult, terra cotta is a low fire clay, and is probably the most used clay worldwide. What I'm saying is a kiln may not be necessary. If you've got a place where you can make a fire pit, which you'll cover, it might work just as well. Maria Martinez, a great potter who used traditional techniques, a primitive kiva, and handmade clay, is still considered to be a great fine arts potter, even 28 years after her death

[bruneama]

Yay, this post is exciting! I am in Lansing (just graduated from MSU) and I am kind of an archaeology nerd. I just finished a class on North American Archaeology where we did quite a bit with ceramics. I haven't worked with clay very much so I can't tell you much about how to do it, but hopefully I can give you some information.

Most of the Eastern part of the US, including Michigan, is classified as the woodland region. The ceramics for this whole region for a given time period were quite similar, although there is some variation. The first pottery in the region is from the early woodland period (about 3,000-2,300 years ago). This pottery is kind of plain and boring. The middle woodland, sometimes called Hopewell, (2,400-1,400 years ago) has some pretty cool pottery, and I think that would be my choice of something to recreate. Late woodland (1,400-400 years ago) pottery is also pretty plain. Hopefully knowing a little of the terminology will help you find more traditional decoration styles.

As far as the process of making ceramics, I know you need to add temper to the clay, make your pot (or whatever you are making), and then fire it. The temper can be something like sand, crushed shell, or fibers like grass. This http://www.uwlax.edu/MVAC/Research/technologies.htm#Ceramics site isn't great, but it gives you a little more information. Most, if not all, early American ceramics were fired in pits, not kilns. People would build fires outside with rocks in them to hold heat. they would then place their pots in the fire and cover it with branches and twigs. I am not completely sure of the process. I watched a video on it a while ago but don't remember it too well. Ok, I found this http://www.nativetech.org/pottery/firing.htm site that explains it a little better.

I'm sorry if my post got a little long. Let me know if there is anything else I can help you with. I don't know a whole lot about it, but I may be able to point you in the right direction. And definitely let us know how the finished product turns out!

Amanda

[kittycitycrafter]

http://www.goshen.edu/art/DeptPgs/rework.html

This site gives lots of details on this subject.  I remember a college near me firing clay pieces without a kiln. I think it was similar to this site.

[DJofTexas]

The first thing you can do is get a piece of clay moistened and knead it for about 5 minutes. Then roll the clay into a snakey piece about an inch round and then curl it around your finger.  If it creates cracks by doing that, you've got too much sand in it for it to be of much use for anything. You should probably take a ceramics class and talk to your professor about the clay.  I just got some clay from the side of a creek in Texas. It was rock hard so first I had to soak it in water for a couple of days.  Then it was too wet, but I decided to squoosh it through a screen to get out any rocks and impurities. It's in a plastic bag in my car now and I will take it to class next week and throw a pot with it.

The first thing you should do is get the rocks and other debris out of your clay.  There are a couple of ways to do this.  My professor says to spread it out thin, let it dry completely, powder it by smashing it up to powder fine consistency, and sift it through a screen.

Me, I just got my clay wet and squooshed it through a screen with a rock.  Much more cavemanlike and primitive.  It was fun.

Next, you need to make a couple of small test pieces and let them dry slowly -- cover them with plastic so that they do not crack from drying unevenly.  It may take two weeks for them to dry completely.  THen they need to be bisque fired in a kiln.  Do not attempt to do this yourself if you've never fired stuff, and only have someone do it who knows about firing pottery -- it is different than firing slipcast molds.  The ramp for firing pottery is waaaaaaaaaaaaay different that slipcast molds because the consistency of the clay is very different and thus the firing ramp (schedule of degree of temperature rise per hour, "soaking" times to allow moisture to depart from the clay so the piece does not explode in the kiln, etc) is waaaaaaaaaaaay different.

Once it is bisque fired, then you need to test it's range so one piecer should be fired to cone 5 and another fired to cone 10.  Then you will know your clay's properties and limitations.

Do NOT add stuff to "temper" it -- you need to test fire it first, because it may be just fine the way it is.  If you add sand or grass to it, you will likely just ruin it.

YOu should probably try to meet a potter who does wood firing or pit firing -- both are ancient methods of firing.  They will be able to help you a lot on your quest to learn to work with raw clay.

It's very fun.  Just there is a LOT of technical detail, and you absolutely CANNOT do anything in your oven.  It won't get the clay hot enough to become vitrious (where it won't turn back into clay when you get it wet).

[PetsuntilEaten]

Nice DJ! That sounds very promising.

Another resource for just about everything is:

"The Self-Reliant Potter" by Andrew Holden

For about every question I had from making clay to creating a kiln.  I researched a ton of various pottery/ceramic message boards & this book seems to be the bible every one swears on - for everything.   It is dated so there are probably some modern concerns not listed in it - i.e. new toxins, eco concerns.  Sadly it is out of print & pricey ($150?) on Ebay or Amazon. *HOWEVER* Your library probably has it, and if they don't have one at your branch I'm sure they'd get it in for you. 

There are some great simple wood kilns that can be made with house or firebrick & no mortar. It won't likely fire very hot, but it's a start. You only need to get to 1000F for the water to escape (or for your piece to explode if you get it too hot too fast) & 1800F for low fire earthenware.  You might not wanna try this during fire season as most places do not like to see smoke this time of year.  Definitely not something you should do in a regular residential area. But here's the links:

http://www.gartside.info/woodkilnintro.htm

http://www.sidestoke.com/firstkilns/firstkilns.html

I've researched an array of homemade kilns, opting for starting with wood burning, no-mortar version like above. Then using the same bricks, expanding with extra materials & experience to a fuller sized kiln. This is really a whole other thread so I won't get going on it here. Hundred ways to skin a cat - a million ways to make a kiln.

Good luck!

[kittycitycrafter]

We just did some deep excavating today and found some clay. I am tempted to try this myself!!! I'll have to give it a better look tomorrow. Hmmmmm....