Ready to fire for cooking, can I get the dome too hot for too long?

[Lavad77]

Casa 100 has had a fire in it for 5 days now. Increased temps by 50f each day from 350f and no cracks! I was worried, as hard to control the temps and sometimes for a minute or two was 100 degrees over target. Now I have seen top of dome black soot clean up and temps when putting in new fuel peak at dome around 750f. The floor is staying around 350f. Thermal layer is very defined ( have seen this in interior structure fires - as I am retired firefighter). Should I be taking the dome temps up into the 1000f plus range and keeping it there to get the oven to equalize at 700 floor temps once thermal balance is achieved? I don't want to compromise the refactor dome cast which I expect could happen even if I raise the heat slowly over several hours?

[Gulf]

Hi Lavad77,

Welcome to the forum. That thermal layering you are seeing can only be cleared up by additional firings. It is partially caused by the massive circulation of cool air entering from the open door circulating through the oven. The other cause is that the floor and lower dome not being completely dry. That massive amount of air can slow the drying of the floor and lower dome. My advice for now is to let the fuel load burn down to just red hot coals with no flames. Then place the door partially open leaving a 1/2" to 3/4" gap. You can also pull a few hot coals to form a short levee across the opening. (I have also placed a row of firebrick across the opening to raise the draft air above floor level) Once the oven is completely dry, the dome should clear completely with just a full firing and your floor temps will increase dramatically.

[Gulf]

Here are a couple of pics of a coal levee that I did this evening. In the straight on pic you can see how the levee is built across the door opening. The other pic shows that the rest of the coals are spread evenly acroos the floor. If you look closely at the pics you can see that the carbon has not burned off completely to the floor line. Immediately after the pics I placed the door about 1/2" from being closed. An hour or so from now I will close the door completely. Though, the dome won't be fully saturated, tomorrow, I will have the temps that I want for the tomorrows cook. It is also a good method for drying the bottom few courses and the floor. The levee raises the draft air slightly above the floor and the partially closed door slows the rapid draft air down.