Re: native pottery part 2

[iowabow]

OK now I could use a little help from you folks! what type of containers do you think I should make and what function should they preform. Some ideas I had were minerial containers for paint, sinew storage, dryroot storage (bloodroot), seed storage,  pine pitch storage, and something to hold feathers. I have not thought about forms yet. What ideas do you all have?

[iowabow]

This is a very interesting article. I learned that the shell tempering of pottery makes the clay workable but leaves it porous. I was going to slip the outside and rub it with a stone to flatten the platelets but this report suggest that this pottery was slipped on the inside multiple times. So now I will cut the clay with water and pour for slip. I looked this morning and figured I had just a little to much clay so this should work out great. This report also support the idea that larger pots can be made if shell is used to temper rather than sand.
http://cladistics.coas.missouri.edu/pdf_articles/SEA17(1).pdf

[iowabow]

all of the pottery sherds i have found along the missouri river and attributed to the ioway in woodland(iirc) times
have very distinct and visible shell fragments as seen in this piece.

until your post i didnt realize they heated the shell. tho i did understand why they used it.
really am enjoying this post and plan on using yr gathered knowledge to produce some primitive pottery.
thanks!

If anone has pictures of pots please post them I would really like to see examples to get ideas from.

[iowabow]

I now have lime which is calcium hydroxide. Everything that i can read says that i need to add calcium carbonate to wet clay. Now the other problem is that they say that the shell was heated and ground to a powder, this would be calcium oxide. So the question is do you add the powder as calcium oxide or as calcium carbonate. See once the oxide hits wet clay it turns to hydroxide. Lime is hydroxide not chalk/carbonate. Help if you have the answer I cant find it in the writings.

[iowabow]

Maybe no connection but lime was added to corn to make it taste better. A pot made with shell would have produced some lime during its use as the calcium carbonate was heated an water present. There is a process called nixtamalization. Maybe not connected but if these pots made corn better tasting then why cook with a different pot.

[iowabow]

I have made a small test coil with the lime added to the clay. I am testing the shrink rate of a 10 inch coil. If it only shrinks 10 percent we should be good. My particle size is very very small and will represent a more refined pottery of the same era (Mississippian). so If you are looking for larger particle sizes then crushing the shells would produce the desired effect as long as you did not refine them too much.

[Stringman]

Keep it coming Professor! I don't have anything to add, but I'm learning alot. 

Scott

[iowabow]

The coil is still wet but new clay seems a bit "short" it cracked and did not coil around my finger well.
I have a few choices
A. Continue with the lime into the clay and then when it reaches working consistency store it and let it age for three weeks. the aging will make the clay more plastic
B. add a vinegar to the clay to decompose the organic material
C. Add another clay body to the material that I have

My clay has a very slow dry rate. This tells me that the particle in the clay are very close together and water is having a difficult time leaving the mix. The lime should help with that but will make the clay less plastic so it seems to me that it is a balancing act here between plasticity and porous nature of the clay I have here in Iowa. At any rate it is going to take weeks before I have answers to all of my questions. 

What I should know is the shrink rate of the clay by tomorrow. Once the text piece has dried then I will fire it in a kiln here at work under controlled environment. so by Friday that experiment will be done.

[Eric Krewson]

This Mississippian bowl shows no sign of shell tempering, others found with it did. They refer to this type as "sand tempered", don't know it that is true.

[iowabow]

Thank you Eric for the photo! you are correct that some were tempered with sand there is a good report I read yesterday about that process. Funny thing.. the lime I have added to the test coil is so fine you would never know it was there. Your pot looks thick so it is most likely sand tempered so far as I can tell from the photo. I like the handle lip and things on the side. Do you know what they are for (the round dot looking things)?

[iowabow]

I have been writting to a few other colleges and universities to get more information about the process. So far not good ...just have not found the right guy that has done a ton of it.

[iowabow]

After 24 hours my coil has shrunk by 3/4 of an inch. I started with a 10" coil. So far this is a good sign. This weekend the kiln will fire this peice to around 1200 degress f.

[Eric Krewson]

I found this bowl back in the 70s before digging up stuff was illegal. A bunch of us were hunting arrowheads on Long Island in the Tn River adjacent to Bridgeport Al. As we walked around a burial mound we noticed someone had dug into the mound and left. It had rained and washed out more of the dig, the bottom of a pot and some rib bones were exposed in the washed out place.

We scratched around a bit, turned out there were 5 pots if I remember right, a complete skeleton from the pelvis up and three trophy skulls positioned around the skull of the main man. My bowl had tree roots growing through it as did several others, one pot was pristine. We took the pots home with us but chose to rebury the the remains of the deceased.

I remember one pot had a frog effigies on the sides, don't know what purpose the round spots on my bowl were intended. We split up the loot, don't know where the other pots ended up.

[iowabow]

Great things are happening the heat shrink test worked out nice. There was very little change in the length durning the firing.

[iowabow]

Crazy results the surface was scratched and the clay was orange. Ok now we have more questions.