The CodyO Show Halloween Special

Happy Halloween

That's right people, three days til Halloween so it's time to release the long awaited Halloween special edition of "The CodyO Show'. On this episode you will see me throwing a bigger version of my thrown pumpkins than the one that I did last time I showed you how to make pumpkins on a potters wheel. This time I use 25 pounds instead of 5.

Also I was overcome with holiday spirit in this episode, so I decided to dress up like a zombie. And given the fact that I would look pretty ridiculous talking and explaining dressed up like a zombie on world wide television, I decided that I would just grunt and make zombie sounds instead.

Hope you enjoy the show and happy Halloween!







More Pumpkin Posts:

If you haven't seen it; I have also done a video on making jack-o-lanterns, I have done a general update after the video, I have answered emails about making pumpkins, I have received a picture of a jack-o-lantern that someone made after watching The CodyO Show and I have shown you a pumpkin that my wife and I made in 2008.

Horse Hair Pots with Leah

In this episode of "The CodyO Show" we have a guest appearance with my wife Leah. She will be showing you how she gets these cool looking black lines on her wheel thrown porcelain vases using horse hair.

When the horse hair is placed on the glowing hot piece of pottery, the carbon released from the burning horse hair is trapped inside the clay body leaving a perfect silhouette of where the horse hair was. It also leaves a sort of shadow trailing away from the silhouette. Horse hair is ideal because it is so thick. I don't think human hair would work. This effect looks great on porcelain because of the nice contrast between black and white.

Check out how it is done!

The Pumpkin of Halloween's Past

Digging through the Halloween box I found this Jack-o-lantern that my wife and I made in Halloween of 2008. Once again, I just made the pumpkin. It was my wife, with the wild imagination, who turned it into this really creepy looking jack-o-lantern. Pretty scary eh? and those lips look really chapped.


From a top view it looks like this jack-o-lantern has blond hair with surfer bangs. This is because with the raku process; the lid of this jack-o-lantern was taken from the kiln and put into a trash can full of newspaper where it would smolder and create different colors according to which side of the piece smoldered more. This was also done with the rest of the jack-o-lantern, however the lid was put into the trash can full of newspaper first. This meant that it was much hotter when it started smoldering than the rest of the jack-o-lantern.


I have found that when I raku hotter I get more gold, red, yellow and orange colors and when I raku colder I get more blue, purple, and maroon. This piece ended up getting a nice contrast between all those colors.

More pumpkin links:

If you haven't seen it; I have also done a video on making jack-o-lanterns, I have done a general update after the video, I have answered emails about making pumpkins, and I have received a picture of a pumpkin that someone made after watching The CodyO Show.

Kiln Firing 10/4/09

Hooray! Another successful kiln firing! That's right people. I don't need no 220 watt outlet with no 50 amps going to it. I GOT FIRE! and what a beautiful thing fire is. :) It lives, It consumes, it produces byproduct, It dies. Same as we do. Fire could almost be classified as alive.....But... anyway......it took some trial and error to try and figure this modified kiln of mine but I think I am finally starting to get it dialed in (for bisque anyway).

In the picture below you can see the top shelf with the pyrometric cones on all four sides of the shelf. The flame comes in at the bottom right of the picture then circles counterclockwise upwards. I space my pottery out more loosely in my gas kiln for this bisque firing than I would if I had an electric kiln with heating coils.This picture is good science because when attempting to get a perfectly even firing I need to consider #1 how even my kiln fires according to it's design, #2 how even my kiln fires according to how fast or slow the kiln was brought to temperature and #3 how the pottery was spaced out (which matters a lot when you think about the radiant heat that each piece is producing). Lets think about those three factors when we look at the picture below:

And here is the Bottom shelf. There are two types of gas kilns: An updraft kiln meaning the heat flows from the bottom to the top and a down draft kiln where the top is sealed and there is an exit hole near the bottom of the kiln that leads to a chimney. I designed my kiln as an updraft kiln just so I would not have to make as many modifications. Because I have an updraft kiln sometimes the bottom shelf ends up firing a little hotter than the top as you may notice in the pictures.

These next two pictures give a clearer view of the cones. Notice that the cone at the top of the picture which shows the top shelf has been fired to a perfect cone 06 because the tip of the cone is just barely touching the shelf. Knowing that you can see which parts of the shelf were slightly hot and which parts were slightly cold. You can also see where the flame enters the kiln and which direction it circulates. I think over all it was a pretty even firing.

And here is the kiln log for this firing. As with any of these pictures you can click on them to enlarge them:

For a description of how my kiln log works and how to read it click here for an older post about how my kiln was designed.

Electric to Gas Conversion: The Birth of My Kiln

My kiln is a gas kiln that was converted from an old electric kiln. I did lots of research so i could figure out what was going to be the best way to convert it. I found some forums online that were very helpful to me and I was able to avoid many trials and errors thanks to these helpful people. Now it’s time to give back. I hope that this section might help others out there as kind of a step by step demonstration.







First, I completely “gutted” the kiln, taking out all electrical components.








This is what the side of the kiln looks like now, on the side of the kiln where all the outer electrical components used to be.


Next, I marked and cut the hole for the MR750 gas burner and regulator combo that I bought at the local pottery supply store (this hooks to a 9 gallon propane tank).



The hole is about a 4” square on the outside, but I cut it at an angle so that when the flame shoots in it creates a spiral effect which will give me a much more even firing. In the pictures below you can see how I drew a couple different angles before I made my cut.


In the next two pictures you can see how I was able to cut the hole in the fragile fire brick without damaging the parts of the kiln that I wanted to keep.

In these two pictures you can see that I cut the hole so that the flame swirls counter clockwise. This is WRONG because I live in the northern hemisphere. If I lived in the southern hemisphere this would have been correct. I have since changed this and now, because of the coriolis effect, I am able to get a much better swirl and a much more even firing. I have the earths rotation working with me, not against me.

Also, when cutting your hole with the kiln section upside down don’t get confused as to which way the flame is going to shoot in when you reassemble the kiln. When you cut the hole with the kiln upside down, know that the angle you cut will be angled in the opposite direction when you flip the kiln back over. Just remember to cut your hole so it is angled the opposite as what these two pictures show, if your in the northern hemisphere. If you live in the northern hemisphere you want the flame to swirl upwards in a clockwise spiral. Hope that's not too confusing. Email with any questions. And for all you skeptics out there who think the coriolis effect doesn’t matter, I assure you it makes a difference. I have tried angling the flame both ways both ways and I have the pyrometric cones to prove it.

Next, I marked out the chimney and drilled holes to help me start to cut the chimney out.

Then I used a hacksaw blade to carefully cut a rectangular shape out for the chimney.

A rectangular shape is used because the heat is swirling through the kiln in a circle and a rectangular exit hole will require the heat to change direction before leaving the kiln, keeping the heat in longer, and making for a much more even firing.


I made the exit hole bigger than I needed it to be for firing so that I could use an old kiln shelf as a damper.




Another very important part about this kiln conversion is that I used square shelves. This helps me avoid getting cold spots in the center of the shelves.

It is important to leave at least 9” between the floor of the kiln and the first shelf so that the flame is not directly hitting the pottery. It is also important to leave at least 4” space between the top of the kiln and any of the pottery. This is because it is colder towards the top.

By the time I had left space at the top and bottom of the kiln and used square shelves, I realized that I had a lot less space for pottery in my new gas kiln than I would have had in a working electric kiln that was the same size. I don’t mind because now I am playing with fire.

Now I want to find another old broken down kiln that is the same diameter as my kiln so I can add another section and make my kiln taller.

Firing My Kiln

The pyrometer (found at your local ceramics supply store) is a crucial part of firing my kiln. The pyrometer gives me a digital read out of the temperature of the inside of the kiln. In the above picture my wife Leah reads a book while she keeps a sharp eye on the pyrometer. She will turn the gas up or down depending what she needs to do to keep to our predetermined firing schedule.


The hand written note on the left was the ^06 firing schedule given to me by someone from the local ceramic supply store. This firing schedule is normally used for electric kilns that have a built in computer to do the job of turning the heat up or down to meet the schedule. Firing schedules for electric kilns with computers are common and can be found for many different desired temperatures.



From the note that the guy at the ceramics store gave me, I made the firing schedule below. I first decided what time I was going to start the firing filling in the column under “time” and “ideal temp”. When firing the kiln, I check the pyrometer at the appropriate time and fill in the columns entitled “temp” and “max temp”. “Temp” is the exact tempature that the kiln was at the time that I checked it. “Max temp” is the hottest temperature that the pyrometer has recorded since the kiln was started (this varies because through the hour you may have to toggle the gas up and down). The firing schedule below is an example of a successful bisque firing. You can see that the schedule has some tolerance. I keep a schedule like this, sometimes known as a “kiln log” every time I fire my kiln. This way I can go back and evaluate my results and compare them to the kiln log.


The pyrometer is not 100% accurate so it is important to also use pyrometric cones so you can check what the temperature was at in different parts of the kiln. In the pictures below you can see melted pyrometric cones. They are melted consistently in different spots on the upper and lower shelfs. This tells me that I got a nice even firing. I stack my pottery in the kiln evenly and with good spacing for airflow. This ensures an even firing. Also in the picture to the right you can see the probe for the the pyrometer poking in the kiln where I had drilled the hole in the side wall for it. This tells us what part of the kiln the pyrometer is getting its reading from.