Uneven firing.........I need help

[Soursop]

Hello all,

I am new here, and this is to be my first post. First off, I'm very glad there is a resource like this out there for all of us who are still working towards a better understanding of our processes and their results.

Ok, so here is my dilemma; I have a 10 cu ft. circular kiln- the maker is unknown(probably homemade), they are stackable "rings" of soft brick. I have 3 burners on the bottom and flat lid with an approximately 4"x4" flue on the top. I fire using propane gas. No matter what I try to do, be it a slow firing (12-14 hours) or a fast firing (8-10 hours), I still cannot get my kiln to fire evenly. The bottom has cone 11 completly down when cone 8 is melted on top. As a result, I have worked with my handicap and developed items that look good either slightly over fired or slightly underfired, but now I am producing more work of greater value and I would really like to stop working with a handicap and fix my problem. So, any advice would be greatly appreciated. Thanks much.

[Mark Norman]

I'm new to the forum and new to pottery but I do have experience in thermodynamics and an engineering background. I too appreciate the forum and hope to glean many helpful tips here. As for your uneven firing I would suggest you post a few pics of the construction of the kiln. How do you regulate the fire of the three burners? Are they independent? Is there a dampener in the flue?

[Soursop]

Thanks for the response, I will try to post some photos over the weekend.