Local clay ok for funtional ware?

[PuraVida]

Hey everyone,

 

Quick question. I harvested a large amount of clay from a bank near my home and it is finally all processed and ready to work with! But now I am debating what to make with it. I want to make some functional pieces with it and have been asked to make a mug from it for a friend. If glazed with lead free will these wares be safe for kitchen type pieces and also what are some things you would check or test when harvesting local clay. I have tested firing temp, and shrinkage already but am curious about what else I need to look into.

 

Thanks

 

Anthony

[Guest alabamapotter]

Hey,

I would feel better about if you made a glazed vase and see if it seeped water when filled. That way you'd know if the clay and glaze were compatible.

If the clay is better suited for non-functional items, then make flower pots and other things. Personally, I dig clay for non-functional vessels, and buy clay

for my cone 10 stoneware vessels. You'll have to do several tests, so make notes for further references.

Good luck,

An Alabama potter

[lcar]

I use my own clay body all the time. Did you do an absorption test? here is a link just in case. http://ceramicartsda...ng-your-clay-2/

 

I suggest making a couple of mugs, test them, use them. See how they hold up. Ask your friend to do the same with the one you make for him. Do some microwave tests to see if it heats up and might burn someone (be careful). Put them through the dishwasher many times and see how they hold up to that. Use it to drink your coffee out of so you can not only study it, but enjoy it. The best way to test something, is use it yourself and observe. Good for you! have fun.

 

Leanna

[Chris Campbell]

Good to hear about potters using local clays.

I am sometimes embarrassed to be so far removed from the clay in my yard. Kind of like kids who think milk comes from the grocery store.

Hopefully some who are using their local clays will write articles about it so we can learn from them and perhaps get a little braver about looking around us and using local clays and minerals.

[Guest alabamapotter]

Good to hear about potters using local clays.

 

Hopefully some who are using their local clays will write articles about it so we can learn from them and perhaps get a little braver about looking around us and using local clays and minerals.

 

 

Pertaining to clays, I enjoy using stoneware clays and natural clays for different reasons. I like using decoration techniques of the 16th and 17th

centuries, particularly the forms, trimming/carvings, springing, and medallions. I like the natural clays for the speed of manufacturing vessels. Its not unusual to dig clay and wedge it within an hour, add 50% sand and gravel, make a bowl and fire it outside in a campfire under 4 hours. Plus,

using natural clays is very mobile, since all you need is a bag of clay and and a few tools. plus sticks & matches. However, most of the vessels

are made the night before or morning of the firings, but you can allow them to completely dry out in 3 or 4 days if you want.

It does require a great deal of practice, research, but if you fire each vessel on its own accord the survival rate is in the upper 90 percent.

Good luck

Alabama potter

[Marcia Selsor]

You need to figure out at what temperature your local clay matures. Then work with it in that range and develop glazes.

Most people used their local clay way before we had distributors.

 

Marcia

[soursop]

You should run a good number of tests with it before you consider using it to make functional pieces with. Most locally dug clays make earthenware not stoneware, so you do need to find out where it matures at. Next check the absorption rate for the clay, and lastly make sure that you have glazes that meet the maturation specifications of your local clay.

 

It'll be well worth the time invested to figure all this out because then you have a very local source of material that you really understand and use properly.

 

Best of luck with it,

 

Please let us know how it goes.

 

-Tim

[Kleipots]

My mountain's clay has got no elasticity at all. I use a space to chip rocks from the slope, soak it in water for a day or so. It then just melts away into a nice sloppy mixture. Then I hang it in a pillow case from a tree branch outside (nice tip I got from this forum) until it feels good. I have to wedge in clay from the local clay supplier just to add elasticity -about 50/50.

Firing is done at earthenware temperature.

 

Thanks again for all the ideas on this forum, I should explore it more.

[PuraVida]

Hey everyone

 

Thanks to all of you for the insite. I have made several mugs with this clay and have been using them myself they are working great my friend is also very pleased with his I found that the clay does not do well at high temperatures definitely a low fire body however very nice throwing quality on the wheel and before its dry it has a beautiful green color to it, post fire a great terracotta color. I'll keep running test as suggested and post pictures when I can. But so far so good Ill have to process some more and let you know how it goes. Again thanks for the help.

 

Anthony

[mrs_christopher]

This sounds so cool. I have been lurking on this topic for the past week, or two, and I have been trying to find some resources for clays around Ohio.

 

I'm still a bit stumped on determining dirt from clay?

 

Anyone have some good resources for this? Pictures would be a major plus!!!

[buckeye]

This sounds so cool. I have been lurking on this topic for the past week, or two, and I have been trying to find some resources for clays around Ohio.

 

I'm still a bit stumped on determining dirt from clay?

 

Anyone have some good resources for this? Pictures would be a major plus!!!

 

I have been doing a lot of research on using local clay and I am in Lancaster ohio so I should be able to find soe good clay. Here is what I have found so far. A lot of people will dig clay and mix it 50/50 with store bought clay because most clay dug up will need grog or sand added to it to make it workable.

 

I am currently looking for a good source of local clay, I really want to make several pieces from local clay and do a pit fire. My brother has 50 acres and a equipment to dig a big hole and it is something I have always wanted to try. I am still debating if I will mix it with another clay that is good at handling thermal shock but most likely will.

 

Clay is pretty easy to spot and if you get out looking for it you should be able to tell the difference once you spot it. Clay will be sticky when wet, very hard when dry, you should be able to take a wet piece, ball it up in your hands etc. good place to find it is in creek beds or construction sites where they have dug a basement or a few feet down, in a lot of places here in Ohio there is solid clay just a few feet down.

 

I hope to start this project soon but if I dont get to it this year I will do it early spring, either way I will post about it and keep you updated

[atanzey]

As a geotechnical engineer in a former life, I can tell you the field tests for clay. First of all, very much of what people tell you is solid clay - well, isn't. It can look like clay but really be silt, which is just slightly larger in particle size. It tends to stay wet, and often has a clay fraction.

 

The tests:

1. Use just a couple of grams worth, and roll a little coil. If you can roll it pencil thin and thinner, it may be clay and at least probably has a clay fraction. If it tends to break apart or "barrel up", it may be silt, or be very sandy clay. (There's an ASTM standard for this, but most people don't really care!)

2. Form a bowel (just thumb size is fine) and fill it with water. The higher the clay fraction, the longer it will hold water. a very fine silt will form the bowel nicely, but will almost immediately break apart with water in it.

3. Dissolve some in water. If you throw, you probably know about how long it takes for the clay to really settle out of your splash pan. Silt will settle quickly, so often you can tell if there's more silt than clay in a relatively short time.

4. (Sort of a lab test, not time in the field) Dry out a small lump. As mentioned above, clay will be REALLY hard to break up. Silt will be pretty easy to crush. Again, you may have both.

[buckeye]

As a geotechnical engineer in a former life, I can tell you the field tests for clay. First of all, very much of what people tell you is solid clay - well, isn't. It can look like clay but really be silt, which is just slightly larger in particle size. It tends to stay wet, and often has a clay fraction.

 

The tests:

1. Use just a couple of grams worth, and roll a little coil. If you can roll it pencil thin and thinner, it may be clay and at least probably has a clay fraction. If it tends to break apart or "barrel up", it may be silt, or be very sandy clay. (There's an ASTM standard for this, but most people don't really care!)

2. Form a bowel (just thumb size is fine) and fill it with water. The higher the clay fraction, the longer it will hold water. a very fine silt will form the bowel nicely, but will almost immediately break apart with water in it.

3. Dissolve some in water. If you throw, you probably know about how long it takes for the clay to really settle out of your splash pan. Silt will settle quickly, so often you can tell if there's more silt than clay in a relatively short time.

4. (Sort of a lab test, not time in the field) Dry out a small lump. As mentioned above, clay will be REALLY hard to break up. Silt will be pretty easy to crush. Again, you may have both.

 

 

thank you for the great info!