I'm not sure the "how or why" of it but there were some small gaps between the soft brick on the interior of this kiln. I am thinking that it has been this way since the original owner built the kiln. There was some fiber in a few of the gaps but I pulled it out and decided to plug all the gaps with new fiber. I cut 1 inch fiber into 2-1/2 inch strips and then kind of peeled the fiber apart into thinner pieces. I then used a plastic flexible putty knife to tuck the fiber into the gaps. Worked real well but was hard on the knees.
My friend Darrel also ran the copper gas line for me, about 50 feet of 1/2 copper and buried it about a foot deep. Next step is to order the 120 pound propane tank and set that in place. Still at it but getting closer.