Pottery Magic Home   Weekly Letter Mail List

Pottery Magic Small Goblets

Pottery and Ceramics Tools

Carbon Burnout Problems And Solutions

Materials used in ceramics contain naturally occurring impurities that can affect the color, appearance and maturing temperature of the piece.

Follow My 40 Day Pottery Challenge

Becca's Montana Girl Blog

Pottery Videos

Pottery and Ceramic Tools

Tools for Pottery

Pottery Magic Wand

Tips & Techniques
for Pottery and Ceramics

Pottery and Ceramic Projects

Clay Pottery Craft Projects

Pottery Magic Wand

Clay Pottery
Articles of Interest

Pottery and Ceramic History

Old Time Pottery History

Pottery Magic Wand

Pottery and Ceramics

Featured Potters Gallery

Pottery and Ceramics Definitions

Pottery and Ceramics

Pottery Magic Wand

All About The Clay

Glazes and Decorating Pottery

All About Pottery Glazes

How a Pit Kiln Works
Digital Kilns, How They Work
How To Pick A Kiln For My Needs
More Info On Picking Out A Kiln
Different Types Of Kilns
Tips for Complete Kiln Care
Monthly Kiln Maintenance
Kiln Safety
The Magical Kiln God
Do I Need A Kiln Vent?
Kiln Sitter
Troubleshooting Your Kiln Sitter
Kiln Firing Gauge
Roman Kilns
Kiln Patching
Kiln Wash
TeePee Kiln Firing
Cooling Rate of Kiln
Coat per Kiln Load
Building a Fast Firing Kiln
Placing, Checking a Witness Cones
How Different Temperatures Effect Clay
Electrical Plugins
Carbon Burnout Problems And Solutions
Cracks In Bottom Of The Kiln
Kiln Temperature Distribution
What Is Your Kiln Trying To Tell You
Pyrometric Cones Q&A
Pyrometric Cone Firing Chart
Common Kiln Firing Faults
What About Kiln Elements
Making Fire Bricks Last
Kiln Furniture
Loading The Kiln
Vegetable Oil Firing
Temperature & Rate Conversion Formula
Kiln Firing Logbook

Carbon which is found in most clays is considered one of these impurities.
Carbon can also be present in the additives and binders which make up clay bodies, slips, decals and lusters.

How Carbon Burns Out

During firing the carbon reacts with oxygen to form carbon dioxide and carbon monoxide gases.
The carbon leaves the pottery as a gas. Binders are burned off at a fairly low temperature such as 300º F to 500º F.
Naturally occurring carbon in clay burns and becomes gases at the higher temperatures up to 1200º F or 1400º F.

The rate at which this carbon burns out is related to the amount of carbon present in the clay.
Some clays have more contaminants than others such as red clays and this needs to be considered when planning the firing.

Air provides oxygen for burnout and needs to be considered when planning the firing. This is effected by several things, a load that is fired very quickly will not allow enough time for the oxygen to react with the carbon, form gases and leave the piece of pottery.
If the pottery is stacked tight during bisque firing, oxygen may not be able to penetrate all surfaces of or inside all the pottery.
Also, if gases are not removed from the kiln and is replaced with fresh air then there may not be sufficient oxygen to burn out the carbon.

Thickness of the piece

Air has to penetrate the entire thickness of the piece and the gases have to escape the same way.
It always takes longer for carbon to burn out of a thicker piece of pottery.
Both time and temperature are important for proper burn out of the carbon.
Some carbons require much higher temperatures that others.
Oxidation should be completed below red heat which is about 1400º F.

Carbon burns out from the surface first and as more oxygen penetrates the body, then more carbon forms the CO or CO2 gas and the burn out process continues.
If there is enough time, temperature and oxygen, then complete burn out occurs.
If these conditions do not exist, the resulting incomplete burn out is referred to as black coring, which is where the center of the piece has a black or gray cast.

Incomplete Burn Out

Incomplete burn out can result from several firing problems including, the bloating of the pottery, if the temperature is hot enough, the outside of the piece will seal up before all the gases can escape.
As the body becomes plastic due to glass forming, gases trapped inside the body expand with heat and cause bloating and sometimes cracking of the pottery.

Glaze defects, such as pinholes, which are cause by the escaping gases, will push through the glaze surface and cause bubbles which pop.
If these do not heal, then pinholes will result.
When ever I glaze a piece of pottery inside and out I never glaze the bottom, which leaves an escape route for any gases or steam.
The pottery will have the appearance of fired bisque when carbon burn out is incomplete and a white clay piece will have a grayish cast and red clay pieces may have a greenish cast.
The body will also be more porous and weak.

Preventing Incomplete Burnout

The best solution for this is to just slow down the firing and be sure the kiln is vented adequately so there is enough oxygen.
When loading the kiln be sure and leave plenty of space between the pottery and the shelves.
Do not stack the pottery, use tile and plate stackers and turn the pieces upside down on top of one another to help conserve space and insure proper burnout.
Now, if you are glazing your pottery, you cannot stack them, because they will fuse together or to the shelf and you will have a mess.
You will have to stilt or dry foot them and make sure they don't touch each other.

Keep your face to the sunshine and you cannot see the shadow<

Tips - Definitions - Clay Projects - Pottery Gallery - Pottery Tools - Glazes - All About Clay

Have you ever come up with a good idea while working with your handmade pottery and thought that you would like to share it with others? You have? Well, why not send it to us and we will add it to the tips page for all to see.

Handmade pottery can be a very gratifying hobby that produces fun and satisfying results. For many people it's an enjoyable release that is created by working an inanimate mound of clay into a beautiful work of art that you made through your artistic abilities.

The best way of starting out is to take a few lessons from Youtube. You will probably waste quite a bit in materials when you first get started. Figuring out how to truly make handmade pottery correctly and shape into what you want it to be can be quite an ordeal. The different tools that a normal shop will have can be fun to try. You will soon see which ones you like to use the most and then when you are ready you will know which ones to buy.

With the help of the internet, you can now purchase most if not all of your ceramic and pottery tools and supplies online. We are located far from any well supplied dealers and yet working with reliable ceramic and pottery suppliers online has allowed us to recieve most of our orders within a timely manner.

When you get all set up, just enjoy the hobby and have fun at it. Some people get pretty serious and start selling their creations at craft fairs and small stores, but others just like to create items for themselves, relatives, and friends. Whichever kind of handmade pottery you desire to endeavor, enjoy the hobby and have fun doing it.

Store Home

DeerLake Store
Outback-Hat from the Deerlake Store
Stash It, Smash It, Crush It,
Tye Dye It, Fly Tye It, Simplify It,
Buy It, the OutBack Hat.

Pottery Magic HomeContact UsAbout
Pottery FAQTerms of Service ~ Terms of Use and Legal Notice
Privacy Policy and Security StatementCopyright/IP Policy
Copyright 2001 - 2017 All rights reserved. DeerLake Designs LLC