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.
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.
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