Pottery at Pete's

[nclonghunter]

A few more....

[nclonghunter]

A point made by Tony Bennett and held by Zuma. Looks like it is in the fire which incidently was firing pots at the time.

A discussion of potters and knappers sharing the same event resulted in;   "Pot heads and stoners"   

[Zuma]

Just fantastic Lyman. :)Thanks so much for posting the photos.
Your descriptions of the events are terrific. :)It was a pleasure to have
spent some time with you and the crew. I hope we do it again.
Zuma

[Zuma]

I managed to salvage a few snaps from
my damaged camera.
Bill built some awesome pots, pipes, etc.
Keith demonstrates a pinch type rim.
Some abo pottery and hardstone.
Zuma

[Ruddy Darter]

That looks like a lot of fun and quite an education,  great looking pots and nice work. That point in front of the fire looks awesome and very primeval, great picture. 


 Ruddy.

[Zuma]

Ruddy,I think you would fit in quite well Yes the hearth aspect of the firing is fascinatingly different.
That's one aspect. The other was actually hydrating the clay with
the stream water. But more than that was our elfish instructor
Keith. Most of our group met Keith for the first time. As did the
check out clerk at the grocery Keith stopped at on his way to House Mt.
She said "Your not like us are you?" He said "No I am from the forest."
He told us "She was still laughing hysterically as I went through the auto doors."
Keith is from the forest, totally off the grid, but college educated and
a real quality guy. I have know him for about 20 years and love em.
Zuma

[iowabow]

Hey Zuma, probably wont get there until Saturday morning. Tom is bringing some items he made and I have one drying from his clay also. Hope to do a pit firing Saturday evening or Sunday with what folks bring. If Keith is okay with it.
I cooked and crushed some shell and added it to some local clay early this year. Fired the pots and they came out looking great. After about a month or so I noticed some cracking and noticed the shell was getting soft and appeared to be expanding. The pot eventually fell apart from the shell expanding. I believe it started pulling in moisture. I also believe I did not crush the shell enough. It may need to be close to sand in size. The pot that cracked is now pounded and crushed into grog and may add it to the clay this weekend. I will also bring the other one for you to look at. It is still intact but has pieces popping off. Again, worst in wet humid weather. Maybe if you cooked in it regularly it may not happen but I do not know.

One thing I read is after you cook the shells, wash them before crushing. Not sure why unless it is to remove ash and dirt from the surface.

See ya soon!

Calcium carbonate oxidation occurs with heat. Key word here is oxidation. This creates calcium oxide add h2o you have calcium hydroxide. The addition of water increases mass.
A pot with shell will self destruct unless you control this equations. Reduction is the key don't oxidize and the pot will not blow up. How do you do that you might ask...keep the pot buried under a high carbon environment. This will allow the pot to sparkle. I discovered this process after many experiments. Preburn is an other subject altogether that i could explain if you like.

[Zuma]

 Thanks Iowa. 
So are you suggesting the shell
tempered pots would be better off pit fired?
As opposed to the open air log/kiln type firing
in the photos.
Zuma

[nclonghunter]

Wood burning gives off carbon if I am not mistaken. I am leaning more to a pit fire for shell tempered pots that is filled with and covered with chopped bark or sawdust to both give off a slow and low heat and more carbon. Those pots we filled with pine bark were black inside from the carbon, which is also suppose to help seal and waterproof it for cooking. I think Keith called it shell bloom or something like that. Before Keith's class I had two shell tempered pots that took in moisture from the air about a month after firing and started cracking and pretty much fell apart. All due to the shell swelling. Sand tempered or quartz tempered pots will not have the same nature as shell so a safer bet.

[iowabow]

Thanks Iowa. 
So are you suggesting the shell
tempered pots would be better off pit fired?
As opposed to the open air log/kiln type firing
in the photos.
Zuma

The powder that he discribed is absorbing mositure from the air and is lime popping. This happens do to expansion. The expansion is a natural continuation of the chemical reaction.
The reduced atmosphere can be achived in other types of firing processes i.e. propane, gas, or wood as you stated. If you would like I can post a picture of a pot that has both example in one pot. Only half of the pot was reduced the other half was oxidized.
Yes you are correct the pit fire will work if you create the environment within the pit correctly.

[iowabow]

Wood burning gives off carbon if I am not mistaken. I am leaning more to a pit fire for shell tempered pots that is filled with and covered with chopped bark or sawdust to both give off a slow and low heat and more carbon. Those pots we filled with pine bark were black inside from the carbon, which is also suppose to help seal and waterproof it for cooking. I think Keith called it shell bloom or something like that. Before Keith's class I had two shell tempered pots that took in moisture from the air about a month after firing and started cracking and pretty much fell apart. All due to the shell swelling. Sand tempered or quartz tempered pots will not have the same nature as shell so a safer bet.

remember the purpose of sand and shell....to improve the quality of secondary clay bodies. Sand historically was used first but its disadvantages were two fold. You had to create a thicker pot and was heavier than shell.
Secondary clays that are SHORT tend to crack because the clay platelets are not uniform. The sand or shell disrubt the movement of cracks caused by this poor quality within the clay.

[Zuma]

Iowa.
If you have the time---
Any and all info on pit firing is totally welcomed.
 Thanks, Zuma

[Jodocus]

those pics with the drying greenware are candy! thanks for these enjoyable Posts!

Iowabow, I also found I Need to fire strictly reductive when limestone is present in the clay.

As to the tempering, sand tends to have rounded edges, wich is not preferrable, it gives much less stability, especially to the wet pot. You can still use it of course for the sake of the reduced work. It's also quite heavy

when you're firing open or in a pit, tempering partly or fully with plant fibers, coal or wood is great. It reduces the ocurrence of pop-offs and cracks big time. Try sawdust, hay or whatnot, but well degraded horse shit is really best. The sun bleached, rain washed kind, that doesn't smell shitty anymore.

Fiber tempering gives you very tension strong clay, great for working slabs or building thin walled.

An organic temper that comes close to grog is crushed nutshells. heavy organic temper will also help to Keep reductive conditions in the clay.

If you want a non-porous surface, or for subsequent polishing, just put on a good layer of think slip on the still wet pot.

[Zuma]

Thanks for your interest and input Jodo.
I need to try some fiber tempering and some slip
application. The shell tempered pot in the other thread
is very light weight. I haven't emersed it in water yet
I still have two more to fire and plan to build more.
Zuma

[iowabow]

This should help with understanding reduction and oxidation. The black is reduced (shell shinny) the tan was in a oxidizing enviroment and is now lime popping. This is a really cool example.