Frequently Asked Questions for Teachers
(Information provided by Clay King)

Clay

1. What kind of clay do I need?

 What do I need to consider when choosing a clay body?
Temperature: lowfire (cone 06-04); midrange (cone 4-7); highfire (cone 8-10)
Color: This will affect your glazing choices
Texture: Groggy or smooth
Intended purpose: Handbuilding or Throwing
Scale: small, medium, large. Larger scale will require more grog
This will mainly affect throwing capabilities

2. How much clay do I need?

For a class of 25 students, you will need at least 25 pounds of clay (1 bag) giving each student 1 lb per small project such as cup, small figurine, pinch pot bowl, etc. 1lb ball of clay is roughly the size of a tennis ball. For more information please see the chart on the Teacher's Lounge Homepage.

3. What are some common terms to use when referring to clay?

Wet Clay: Malleable, fresh workable clay ready for building
Wedging: kneading the clay to make the clay homogenous, to align the particles, and to remove air pockets.
Handbuilding: pinching, coiling, slab building
Wheel Thowing: Throwing pots using the potter's wheel
Slip and score:
Leatherhard: clay that has died out some, but is still slightly moveable and has not started to change colors yet. This is a good stage for attachments.
Greenware: bone dry clay that is ready to be fired. MOST FRAGILE state of clay
Bisque: 1st firing to drive off chemical water to make the clay ready to accept glaze.
Glaze Fire: Firing of the clay and glaze to make a glass like surface

4. Can clay go down the sink?

No, it will clog the pipes. You should have a recycle bin for scraps for reclaiming and install a sink trap to catch the finer particles.

5. Can I recycle my clay scraps?

Rehydrate the scraps with water. If too wet, dry out on plaster or canvas. Then wedge the clay together to make the clay all the same consistency. This clay can also be mixed with fresh clay. You can use a pugmill to make the reclaiming process easier.

6. What is a pugmill and how do I use it?

A pugmill is a piece of equipment used to assist with reclaiming clay. Different machines have different qualities. Things to know about pugmills: mixing only or do you need de-airing? De-airing will need a vacuum. Stainless versus Aluminum? This will depend on the clay that you are using. If using stoneware or porcelain you will want stainless steel. Size and space it takes up in the studio. Tabletop model or free standing floor model? And don't forget to make sure you have the correct power for the machine.

7. Does clay go bad?

No, but it may grow mold. This is good bacteria and will be good for the clay's workability. It is not harmful bacteria. It can also dry out, so keep it covered and add water as needed.

8. How long can I keep my clay?

Indefinitely as long as you keep it hydrated. Rehydrate if it does dry out.

9. What happens if my clay freezes?

It is still useable after it thaws out, but it will need to be wedged.
 

Surface

1. What is the difference between paint and glaze?

Paints, such as acrylics, oils, watercolors, pastels, etc, are a cold surface techniques and do not require firing. When using paints, it is recommend to seal the surface with a spray sealer. Glaze is a specially formulated material that is to be applied to bisque and then fired to form a glass like surface.

2. Does Clay-King.com sell paints and sealers?

Yes, Duncan makes a great line of non-fired paints and sealers for ceramics.

3. How many coats of glaze do I put on the piece if I am brushing on the glaze?

2-3 flowing coats

4. What is the difference between slip and underglaze?

Underglaze is a commercial product available in a wide array of colors that can be applied to leatherhard, bone-dry work, or bisqueware. Slips can only be applied to leatherhard clay.

5. How much glaze do you need for each piece?

1 pint of glaze will cover about 8 mugs or 12 cups.

6. Does glaze keep and for how long?

Yes, it may need water added as time passes to keep the ideal consistency.

7. Can I rehydrate my glaze if it is dried out?

Yes, just add water and give it a little while to hydrate and then stir. Once mixed to smooth consistency it is ready to use again. It is ideal to run it through a screen or sieve, but not required.

8. What is a wash and how do I use it?

A wash is an oxide mixed with water and usually some sort of suspending agent for ease of use. Washes are great to put on a textured surface and wipe away the excess so that it is only in the recessed areas. Then you can apply a translucent glaze or if on an exterior of a functional item or on a sculpture you can leave just the wash and then fire it to your target glaze temperature.

9. What are some surface embellishment techniques?

Stamping, stenciling, masking tape to mask off areas such as stripes, slip or glaze trailing, sponging, etc.

10. Are glazes food safe?

Most are non-toxic and food safe, but it is important to read the labels to make sure.

11. Are glazes mixable like paints?

Some are and some are not. All underglazes are mixable like paints. All of the AMACO Teacher's Palette Series as well as the Mayco Stroke and Coat Series are mixable like paints.
 

Safety

1. Can you eat off of and drink from the ceramic items the students make?

Yes, as long as you are using a food safe glaze. Most of the glazes we sell are food safe, but some are not. Read the labels carefully.

2. Can ceramic dishes go in the microwave and the dishwasher?

Yes

3. Can ceramic dishes go in the oven?

Yes, as long as you preheat with the dish in the oven so that it warms up slowly.

4. Is clay toxic or dangerous?

No, but clay dust is bad for your lungs. You should never sweep it up, always wet clean your studio and wear a dust mask when cleaning up.

5. Are electric kilns dangerous? Do they catch on fire?

Kilns if wired properly with the correct voltage, phase, and breaker size, are not inherently flammable. However, if you have flammable items near the kiln, it could cause some problems. For instance, do not leave ware boards or newspaper on or near the kiln when firing. These items are flammable and could catch fire.

6. What is an MSDS sheet?

MSDS stands for Material Safety and Data Sheet. The sheets let you know how safe your material is and what percentages of minerals are in the product. MSDS sheets can be obtained for most any material including clay and glazes. Go to the manufacturers website to download a copy. It is not a bad idea to keep a copy in the classroom to comply with Environmental Health and Safety laws.
 

Purchasing

1. Can I purchase with a Purchase Order?

Yes, just fax over your PO to 864-579-1756.

2. What are your terms for using a Purchase Order?

Net 30

3. Do we have to pay with Purchase Order?

No, you can pay with any major credit card. We also accept cash (if picking up at our location) and checks. You can place your order online and check the appropriate payment method. Please note that if paying with a check, your order will take longer, as it will not be processed until payment is received.

4. Do we pay sales tax?

You will need to pay sales tax. If your school is tax exempt, fax over a copy of the tax identification sheet with your PO or email us a copy to have on file in the store.

5. How do we obtain a W9 form from Clay-King.com?

Either give us a call or send us an email and we can email or fax you a copy.


 

Equipment

1. What equipment would be good to have for a classroom setting?

Kilns, wheels, extruder, slabroller, pugmill, clay, tools, stamps, and glaze. See our teacher packages for great ideas to fit a variety of classroom needs.

2. What do I need to do to maintain my kiln?

Periodically vacuum out the kiln, making sure to vacuum the elements channels. If you have the unfortunate experience of blowing up work, be sure to vacuum out the kiln and element channels after unloading. Wash one side of you kiln shelves with kiln wash. If glaze gets on the kiln shelves, be sure to remove it before the next firing. If you do not, it will continue to fire into the kiln shelf and destroy it. To remove it scrape with silicon carbide scraper. For stubborn areas, wear eye protection and use a hammer and chisel. Then wash the kiln shelf with kiln wash.

3. Can I use kiln shelf paper instead of kiln wash?

No, shelf paper is used for glass only.

Firing

1. What temperature should I fire to?

Firing temperature will depend on your clay and glazes.

2. What is the difference between cone 06 and cone 6?

Cone numbers with a zero in front are like negative integers. For example cone 06 is cooler than cone 05. Imagine a horizontal line with zero being in the center. On the right side of zero, are increasing numbers 1,2,3....10. The progression in numbers gets hotter with temperature. On the left side of zero, you have 01,02,03,04....021. As you get further away from zero, you get cooler in temperature. So, there is a huge difference between cone 06 (1836 degrees F)and cone 6 (2232 degrees Farenheight).

3. What do I need to know prior to buying a kiln?

voltage: 240 volts or 208 volts
phase: single or 3
size desired: interior dimensions. If you do not know, we recommend that you mock up the interior space with cardboard or paper, so that you can visually see the stackable space.
breaker size: each kiln will need a big enough breaker to support it. This is listed on each kiln page, but you will need to know what your building has or can handle.
plug configuration

4. What is single or 3 phase mean?

This is how the power is broken down and delivered into the building. Check with your school's electrician.