Well, the floor (so far) was a success. We reamed out the burner orifaces to #28 for gas (turns out they were propane orifaces) and set everything up and gave it a whirl. Worked pretty well! I think we have the fuel/air mix off a good bit, but we were still able to get the kiln to 1,900 degrees in just a couple of hours. Some photos:
The floor, in place, with burner ports cut:
Detail of burner head and port:
Low flames on the first firing:
At full burn, just before we shut it down:
After cutting off the gas:
The goal is to get the thing to cone 10. We have a long way to go, and I can tell that the 4-500 degrees above 1,900 we need to get are going to be hard-earned. But I think we can do it. There's certainly no shortage of gas...we got it to 1,900 degrees with the valve barely cracked. Soot around the lid in places where there were heat/flame leaks tells me that the mix was probably starved of air, but that's just a guess.
Very excited at the success so far, but not sure if we need to increase primary air (with the burner venturi shutters), secondary air (with larger burner ports...we cut them pretty small) or both! Time and experimentation will tell.
Looks like the next project for this thing will be to rebuild the lid. After the first firing (probably in a decade) the part of the lid near the hinge was crumbly and falling apart. I can see the whole thing crashing down through the kiln and crushing the floor, so maybe we should replace it sooner rather than later. I really dislike the hinge system that olympic devised for this kiln. Seems built to fail. The lid is pretty heavy, and all that supports it when it's open are a couple of brackets that are attached to thin sheet metal that gets all of it's structural integrity from the K-23 firebrick that it's squeezing. Bad design. Was thinking that it might be good to weld up a frame to go around the kiln and create a "bridge" over the lid with a pulley system so the lid can be lifted with a little winch, kind of like how some raku kilns are designed, but only lifting the lid. Anyone ever see something like that?