Author Topic: Re: native pottery part 2 (Read 27012 times)

JW_Halverson · « **Reply #30 on:** August 30, 2012, 11:01:52 pm »

No need to break it up into smaller bits? Just drop in the big chunks and it melts away?

iowabow · « **Reply #31 on:** August 31, 2012, 01:12:00 am »

Thats correct but it needs to be very dry. Tomorrow JW I will mix the clay and screen it. The pictures should help.

iowabow · « **Reply #32 on:** August 31, 2012, 03:56:41 pm »

processes photos: First thing was to check to see if the slump worked and it did great. I stirred the mix about 25 times and it was perfect.
1st photo, shows the surface with no wood particles.
2nd photo, shows the minor lumps
3rd photo, shows me stirring the mix.
4th photo, The mixing changes the SP of the mix and causes the waterlogged vegetation to float then all you need to do is strain it off the top before the particles settle.
5th photo, Shows the straining larger rocks out of the mix.
6th photo, The rocks.
7th photo, the clay is stirred agian and the top is poured off to remove heavy sand particles
8,9,10, 11 photos. The mix will settle and the water can be removed for faster drying.

iowabow · « **Reply #33 on:** August 31, 2012, 03:57:26 pm »

the rest

iowabow · « **Reply #34 on:** August 31, 2012, 03:59:15 pm »

The heavy sand in photo 8 is tossed

iowabow · « **Reply #35 on:** September 03, 2012, 12:36:32 pm »

After a couple of days the clay settled to the bottom half of the bucket and the water rose to the top half. I then poured the water off leaving just the slurry of clay.

Today the weather is great and presents an opportunity to test cooking shells on a large scale. With a pile of wood and a 5 gal bucket of shells, I built a layered box fire as seen in the pictures below. I have no idea how this will turn out! I also placed a couple of rocks that I thought had iron in them to see if I can get a color change. Again I have no idea if this fire will produce the red iron results I am looking for. On a fun note the cut wood was from an ash tree that was hit with lightning.

iowabow · « **Reply #36 on:** September 03, 2012, 12:45:48 pm »

Note... I used a metal fryer pan to strain for rocks a weaved basket would serve as the same tool in a primitive studio. Skin pots, wooden bowls or ceramic pots would serve as a replacement for plastic buckets.

BowEd · « **Reply #37 on:** September 03, 2012, 01:30:07 pm »

You have the most natural desire to see stuff metamorphasize[don't know if that's a word]that I have ever seen.Keep on truckin......LOL.

iowabow · « **Reply #38 on:** September 03, 2012, 08:58:43 pm »

The shells are now slake lime but some part are not breaking down so I need a filter to pour the slake through but have not figured out how yet. I think I should have let the shells sit for three weeks to turn to powder. I am still learning this process. I cant decide if I should leave the solution till morning or filter it tonight.

iowabow · « **Reply #39 on:** September 03, 2012, 09:47:53 pm »

I went to town and an hour later more broke down so I am going to let it sit over night and all day tomorrow and just let nature do its thing.

iowabow · « **Reply #40 on:** September 04, 2012, 12:05:19 am »

I think that adding water was not the simple process but rather a faster process to reduce the shell to powder. If you just place a burnt shell on a table it will reduce to powder by taking up co2 from the air. This process requires a long time. I figure that if I lived in a fire heated lodge this process would be accelerated. Using water will accelerated the breaking of the shell but it will still need to be dried and CO2 will still need to be taken up. I am still not sure which will be faster. I do know that the water process is more human energy consuming. I have worked out a plan to remove the processed lime. I will stir and pour off the lime material leaving the heavy stuff that did not reduce. This bucket will settle and the water poured back and the process repeated till all reduced material is removed.

iowabow · « **Reply #41 on:** September 04, 2012, 09:43:55 am »

With rain coming I changed plans and poured off the fine particles this morning. The heavy material measured three inches in a 5gal bucket. I feel real good about the burn and should have the amount needed to produce the clay in a few days. The clay will take about two week to be ready. So now I will wait and pour off water as it comes to the top in with both clay and lime.

iowabow · « **Reply #42 on:** September 04, 2012, 09:54:50 am »

Its a good time to remind folks why the calcium carbonate is added to the clay. It will reduce shrinkage during the making of a pot and this helps prevent cracks that form during drying and this material acts as a thermal shock absorber reducing the occurrence of cracks during firing.

sadiejane · « **Reply #43 on:** September 04, 2012, 10:47:48 am »

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!

iowabow · « **Reply #44 on:** September 04, 2012, 11:53:17 am »

We should have pottery that looks very similar to the example you posted. The particles in many cases are as follows; very small, the size of sand and maybe a little larger. There was a really good paper I read about a site that was excavated and unfired clay was found. They could tell that the shells had been cooked before it was added to the clay. If you take a shell and hammer it into dust you will spend hours getting it processed (you will have the same product as my process). Using the heat and reducing using a dry method (air) or a wet method (water) should produce the same product...calcium carbonate.

In my process I kept the heavy material to examine more closely for particle size and so I can compare it to the lime particles. The picture you posted really seems to support the prefire idea because the particles look very fine and seem more rounded than the pottery I made by crushing the shell rather than burning it for reduction. My first pots had shard like particles because of the hammering. Your photo is great because you can calculate the percent based on the color change (some what), this supports the 20% idea of clay to shell.
I have really expended very little energy in producing the lime and much less than I thought I would with the filtration process.

Filtering the lime...I mixed the shell in a wheel barrel with water (4 gals) and poured off the suspension of material in to a 5 gal bucket located at the right front of the wheel barrel. I then added more water to the mix (about 2 gal) then mixed and poured the contents into an other bucket. I did this one more time with 1.5 gals of water and this was very clear by this point.

Settling the solution.. I went into the house ate and took a shower by the time I returned the lime and the water had separated....then I poured the water off and into the bucket of undissolved shells so I could save it till later. I then combined the two buckets of lime and set it off in a sheltered area.

notes.. I saw a scum on the surface of the water before pouring the water off.. I guessed that it was the surface lime reacting with the air and taking up CO2. These sheet that looked like sheets of ice were poured off with the water as well as minor contaminants floating on the surface, grass, small pieces of burnt wood, and other unidentifiable particles. Surprisingly I now have what appears to be a rather clean sample of calcium carbonate in a quantity that is useable and required very little work other than the thinking part about what would be the most simple and primitive method of mass production. This would have been very easy to do during this time period. The only modern equipment were the containers, a rake, and tongs. All of which can be substituted for containers of that time period. I just don't have the village of materials to draw on to demonstrate this with primitive tools. I will however when I start firing this pottery! hehe