MikeSible

Thanks to everyone for your help on this. I'm not actually looking to get to cone 10, I was just illustrating that I have enough in the BTU dept. to get to there on a windy day. I'd be happy with cone 06, probably. 04 hopefully, just a hard bisque. But, I will add some fiber, bulk up and increase the fire box size, and try a chimney again. Thanks again!

Sorry, all. Turns out whiskey + math is not a good equation. The kiln is 36" tall, so the cubic feet is roughly 18. Math = (3.14 * 16.5^2 * 36) / 12^3 . The burner is the MR100 venturi I purchased from Ward Burner Systems after consulting with them. The fiber is 2" of 6lb. and 1" of 8lb. It is an updraft kiln, with a flue. I was using the term flue when I should have said chimney. So, I tried a chimney at one point, but generally don't have one. I believe the specs I found suggested a port size of 1 1/2 times the size of the burner and the flue I started with was approximately 4-5 inches by 4-5 inches, but I ended up making it slightly larger and then adjusting the size during firing by draping pieces of fiber over the edges to cut down the size. When firing, I start with the burner inside the firebox during the candling and gradually move the burner to the outside of the kiln to about an inch away. Like I said, I've experimented a lot with the flue and port sizes, but with little effect. I've tried adding a separate port just for extra air as well. Also, the kiln is in two parts, so I can fire using just the top half, which is probably about 10 c.f., which also doesn't seem to affect the overall temp capabilities. Thanks for your quick responses .

Hi, I'm looking for help with my kiln design. I am having trouble getting it to temperature most of the time. It is ceramic fiber, cylindrical, approximately 50 c.f. and propane fueled with a 500 gal tank. I don't have the exact btu available, but I believe it is more than enough, with a single burner. I primarily fire it with a saggar, which is made of hard brick, also cylindical, that sits and fits exactly on a 26" round shelf. The fire box is about 4 inches tall, made of soft brick, which supports the fiber shell. The gap between the bottom shelf and the wall varies between 3 and 4 inches while the gap between the saggar wall and shell is about 3.5 inches. The gap between the top of the saggar and the roof can vary from between 3 and 7 inches, with little difference noted in performance. It generally peaks out at about 1800 deg., however when it windy, I can get it up to 2200+ without any trouble, so obviously there is an air flow issue. I have experimented with innumerable combinations of vent and intake size, including a flue, although most of the time I haven't had a flue. It seems once I get the vent large enough, I just start losing heat. Is my only solution a blower? My other thought is to rebuild the roof so that it is more of an arch. Any help is very much appreciated. Thanks.