My friend and I recently bought a used kiln and wheel.
Our first test with the kiln we messed up and fired our stuff to cone 6 (instead of 06). We hadn't had a lot in the kiln, just a few really small cut-out pieces. It took about 6.5 hours to get close to cone 6, but the large 6 cone didn't fully drop, and the cone 7 didn't really move much, so we weren't totally sure if it was fully done.
Moving on to our second fire. We had new things to fire, so we bisque fired our stuff (half full with things stacked) to cone 06 this time. Our cone sitter fell out when we closed it (not sure exactly what happened), so after 6.5 hours, we stopped it. We again weren't 100% sure if things we underfired, overfired, or totally perfect. We tried the "lick" test and it was sticking to our tongue. We decided to glaze it and fire to completion. This time, our kiln was full. We didn't put anything on our bottom level (we were worried out glaze would run and it would ruin the kiln). We put in a cone 7 sitter (to make sure it fired completely to cone 6) and we had our large cones to watch at the top and bottom of our kiln. After almost 11 hours, it still wasn't complete (and it was 1am) so we turned it off and left it.
So now I'm left with a million questions.
1) How can I tell if it is completely fired?
2) Can I re-fire the stuff and would I have to fire it from start, another 12+ hours?
3) I've read a million posts talking about different kiln lengths, but I'm wondering how exactly you can tell how long it would take?
4) I think our bottom heat isn't as strong as our tops, so should I be putting thinner stuff at the bottom? Or just get the heaters fixed?
5) If our bisque fire wasn't fully fired, would that make our glaze fire take longer?
Thanks so much for any help! Already this website has been a huge help for my friend and I. We basically use this as a pottery bible.
We re-fired our glaze and this time everything went off after 8 hours. The glaze is a little runny, but our main concern is the bottom elements not being the best. We had our thin stuff at the bottom, and it did glaze over, but the cones didn't change at all. The top cones did, though!