Clay Testing

[synj00]

On thanksgiving and without a change of shoes we journeyed deep into the wilderness to gather clay from a sacred and ancient ritual site once used by the Navajo. Just kidding, it was Thanksgiving though and we didn't bring a change of shoes.

 

 

The site we chose was just a few minutes away and had a good cut into the side of a hill which gave a good spectrum of colors of clay.

 

My son helped and it was a great bonding experience to be out digging the clay.

 

Here is our haul, 4 gallon bags of different color clays.

 

You can see the difference in colors a bit better in this shot.

 

I've got the first test batch going using the water extraction method. It was very "clay-like" right out of the bag and a medium red. I've got a very dark red and an orange red and a very light orange"ish" which is the most sandy of the four.

 

 

I saturated the clay for 24 hours and strained through a piece of fiberglass window screen. Do you think that is enough or does it need to be finer? Anyways its drying now outdoors and I'll see what we come up with when it gets to the right moisture level. I think I should be able to add this to my white body clay to give it some good color even if its unusable. Or maybe us as slip. I've got 3 more batches to go. I'll post some results as they come.

 

 

[Biglou13]

What is water extraction method?

[Mark C.]

What is water extraction method?

I think its where you put the material in an espresso maker and force water thru it for a good cup of mud or that's my guess?and its just a guess.

Maybe its floating off the wood and other debris letting the clay settle out?No steamed milk?

I have been in the studio to long.

Mark

[jrgpots]

I found a vain of gray clay between two layers of sandstone. I slaked it, screened it, and made a 10 inch test strip. When fired to cone 05 bisque, it turned a beautiful yellow cream. It is firing to cone 5 right now. Hopefully it will mature without melting at cone 5. It is very plastic and smooth. At bisque, shrinkage was 7.5%. We will see what happens with firing.

 

Synj00, isn't it fun to go prospecting?

 

Biglou13, I may have found a complete natural clay that is so smooth to throw. I'll post pics of my first mug with the stuff. I have also made a terra sig out of a bentonite/kaolinite local clay. Remember the "dog poo" clay that melted into a chocolate mess? I used it to make the terra sig. It survived bisque firing and is in the kiln to cone 5. My fingers are crossed.