Hello everyone! I can across this forum through some Google searching and it had some good information so I thought I would join.
I throw stoneware and fire to cone 5/6 fire for my glazes. I started with clay at age 8 and starting throwing at age 12. Now being 22 I've been at it for a while (whenever free time allows).
Anyways, to set the background to the question, I have an old manual Jen Kens kiln I got used 12 years ago. We were not sure how old it was when we bought it but after having the local kiln repair guy replace a bad switch 3 months ago he mentioned the kiln was at least 30 years old and in great condition because it didn't appear used much for its age. I talked with him about knowing when it was time to replace the elements. I've never replaced them since I owned the kiln and I have no idea when the previous owner replaced them because he had past away and it was his family selling the kiln. I have fired this kiln at least 125 (probably more) times since I have owned it (first 3 years cone 06-04, last 9 years 04/05 bisque and cone 5 for glaze).
This is my first kiln so I have no other kiln to compare firing times to, to tell if the firing times were too long to begin with. So I wanted to get an idea of what others firing times are for certain cones. I know it depends on many factors but I wanted to get a basis.
My kiln (approximately- my kiln usually varies .5 hours to and hour depending on load size):
Cone 04/05 7.5-9 hours
Cone 5 14-16 hours (on average- one load took 12 hours and had one load take up to 18 hours)
Recently I have been monitoring this kiln more with the pyrometer. The kiln gets to 2000 degrees in decent time (in my opinion), but it seems the last 150 degrees are taking longer than it should be to get to a cone 5. The last 150 degrees it is at least 5-6 hours of the firing.
Thank you in advance,