“When you know stuff you can do stuff”. This is a quote from a very prolific ham radio homebrewer, Pete Juliana, callsign N6QW. It is possible that he has built more homemade transceivers of unique designs than anyone else.
In high school I read a lot of books and skimmed dozens of others. In total I believe that this was more than 100 books. Most were from The Detroit Public Library but also included my local library, my school library, and a bunch of books I bought with money earned from singing.
I tended towards books that were technical but not at the level of Engineering. Although I did take some engineering books home to look through.
This voracious appetite for ceramic reading did not stop until the late 1970’s. When at the Archie Bray Foundation visiting I read through everything I could in the library and skimmed many other books. What I learned in that library helped me be successful at many things a few of which I can track.
But it is not just books that have value to read. Instruction manuals for kilns have a lot of important information. The Orton Foundations literature on temperature, cones, and other measurement devices is very helpful. Omega Engineering used to have a product application book that had a bunch of basic knowledge on thermocouples that I have found useful.
The AP Green book on bricks was a great read. It informed how I built kiln walls. There was something called The Gas Consumption Handbook that I enjoyed.
These days of instant information people love to ask questions online. The amount of laziness and lack of reading is palpable. Page 32 of the latest Skutt Manual has the Error codes. Before you ask a question here you should at least have the courtesy to check the manual.
This does not mean that I won’t answer these questions that should be easy to find answers to. Nor does it mean that sometimes things don’t fall through the crack of our acquisition of knowledge.
But when you know stuff you can do stuff. Most of my new ideas require knowledge in order for me to evaluate them and then to implement them. In Studio Ceramics a good place to start is a basic textbook as it can provide a framework for further knowledge and gets you started with a broad understanding. I suggest Nelson’s “Ceramics: A Potter’s Handbook” any edition. The pictures are better in the newer additions. They can be found for less than $10.
Monthly Archives: August 2026
A Guide to Combustion for Clayers
Clay workers usually heat things up. There are exceptions, but they really are exceptional uses. In order to fully understand our processes we have to understand how things combust and what biproducts this combustion produces and at what temperatures.
The players:
Oil, fossil or vegetable. I suppose animal oil as well.
Coal
Charcoal will be handled under wood as will sawdust
Natural Gas Methane
Propane
This paper will not be fully footnoted if it is footnoted at all.
In order to understand combustion you really have to know something about how molecules are bonded together. Molecular bonds hold cellulose molecules together and also hold methane and propane together. Methane holds four hydrogen atoms to one carbon atom, CH4 . In order for methane to burn you have to add enough energy into the system to break the bonds between the atoms so that they can recombine to form new compounds that are more tightly bound together. Because they are more tightly bound together this releases heat. So it takes heat to release more.
When you heat up organics bonds break. Long molecules like cellulose become shorter. Some of these shorter elements recombine to form new compounds. At low temperatures these generally do not break far enough to then burn to carbon dioxide and water vapor, although there can be some We get mostly other organic compounds.
Initial heating up to 200˚C produces acetic and formic acid, and perhaps a small amount of carbon dioxide, glyoxal and water. Glyoxal is a dialdehyde. What happens in the next temperature zone 200˚C -280˚C is similar but with possibly a bit of carbon monoxide formed. So far the reactions are endothermic. The absorb energy. They do not release heat.
Above 280˚C the reactions become exothermic, they release heat. You get carbon monoxide and dioxide, acetic and formic acids, formaldehyde, water vapor, methanol and hydrogen. There is also some vaporized tar. If you hold a piece of wood at 400˚C by the time the temp has reached the center of the wood it will have stopped smoking.
Your nose is able to detect aldehydes in very small concentrations. To my nose, most bisque kilns if the clay is not quite pure, smell like dirty vanilla. Vanilla is another aldehyde. There are some quite nasty aldehydes, formaldehyde being a notable one. acetaldehyde, and acrolein are others It is smart to limit how much of these chemicals you breath. They can cause oxidative stress and DNA damage. Vent your indoor kilns. Its smart.
The organic acids are hard on the metals surrounding your kilns. They can eat metal roofs above kilns, remove zinc coatings,but first they generally rot the band of your kiln lid. You want these to leave your kiln as soon as possible so keep a top spy open at least before red heat, and to protect your indoor space,,,
Vent your kiln.
Its not like you smell your kiln once and fall over dead. These chemicals are also produced by candles, incense, campfires. Gas kitchen stoves produce formaldehyde according to recent studies, but also benzene and other hazardous chemicals. These chemicals are part of the issue with cigarette smoke that makes it so carcinogenic.
Its easiest to just look at one kind of fuel, but unless we are talking about hydrogen gas as fuel the basic principles are all the same. I like using methane, the main constiutent of natural gas that is delivered in pipes from central gas plants in the US. Methane mentioned above is CH4. Heated with oxygen it burns. If there is enough oxygen then most of what you get is CO2, carbon dioxide and H2O, water in vapor form. While a net heat is produced when the carbon and the hydrogen in CH combine with oxygen, there are two places in the process that produce losses. . One is the energy it takes to break the bonds between the carbon and hydrogen. The second is that the water that occurs is in vapor form. When it leaves the kiln and cools it condenses releasing heat as it condensces. Since it started as gases this is not really a loss in some senses but if you could condense the gas in the kiln it would release heat.