Danny Posted May 23, 2020 Report Share Posted May 23, 2020 Hello I am new to firing ceramics, I have a tiny RC-16L Electrical muffle kiln. My bisque firing schedule has been C-01- starting point 0005 - T-01 = 0180 (3 hours) - SET- C-02 = 0600 - SET- T-02 = 0000 (minimal required soaking time) - SET- C-03 = 0000 (confirming soaking temperature) - SET- T-03 = 0090 (1.5 hour to reach 1060C) - SET- C-04 = 1060 - SET- T-04 = 0000 (soaking time for this temperature)- C-05 = 0000 (confirming soaking time) - SET- T-05 = 0180 (time to cooling down to room temperature) - SET- C-06 = 0020 (20 C room temperature) - SET- T-06 = 0000 (stop program) The bisque seem to be coming out has they should but I feel that I am firing wrong. I've tried a cone 6 glaze firing by following the same schedule and changing the max temperature to 1240 What do people think? I'm having a melt down. Link to comment Share on other sites More sharing options...
Bill Kielb Posted May 23, 2020 Report Share Posted May 23, 2020 22 hours ago, Danny said: Hello I am new to firing ceramics, I have a tiny RC-16L Electrical muffle kiln. My bisque firing schedule has been C-01- starting point 0005 - T-01 = 0180 (3 hours) - SET- C-02 = 0600 - SET- T-02 = 0000 (minimal required soaking time) - SET- C-03 = 0000 (confirming soaking temperature) - SET- T-03 = 0090 (1.5 hour to reach 1060C) - SET- C-04 = 1060 - SET- T-04 = 0000 (soaking time for this temperature)- C-05 = 0000 (confirming soaking time) - SET- T-05 = 0180 (time to cooling down to room temperature) - SET- C-06 = 0020 (20 C room temperature) - SET- T-06 = 0000 (stop program) The bisque seem to be coming out has they should but I feel that I am firing wrong. I've tried a cone 6 glaze firing by following the same schedule and changing the max temperature to 1240 What do people think? I'm having a melt down. Here is a basic schedule below. Bisque firings generally take the most time so everything is burned out completely and slowly. Glaze firings are generally much quicker. The medium fire schedules below are probably most common. The important part of the glaze firing occurs in approx. the last 100c or 200F. This ramp speed should be set per the Orton cone chart to reasonably get the wares fired to the cone picked. Using firing cones will confirm what your wares were fired to. The schedules below are popular, you will need to convert them to Celsius. I would suggest trying first the slow bisque to 04 (13 hrs 26 minutes) and the medium glaze cone 6( 7 hrs 37 min) Verify each with witness cones so you know what it fired to. Finally let them cool at their own speed until you understand what slow cooling does for you. So when the firing is done, everything gets shut off and cools on its own, unpowered. Link to comment Share on other sites More sharing options...
Danny Posted May 23, 2020 Author Report Share Posted May 23, 2020 Thank you so much for your reply, I will try these schedules! In my last glaze firing I put in the pyrmetric cone 6 and it bent fully, but didn't feel confident with my firing schedule. Should I switch my kiln of when it reaches max temperature? I've realized an error I've probably been making is a required time to cool the kiln down lol Link to comment Share on other sites More sharing options...
Bill Kielb Posted May 23, 2020 Report Share Posted May 23, 2020 1 hour ago, Danny said: Thank you so much for your reply, I will try these schedules! In my last glaze firing I put in the pyrmetric cone 6 and it bent fully, but didn't feel confident with my firing schedule. Should I switch my kiln of when it reaches max temperature? I've realized an error I've probably been making is a required time to cool the kiln down lol No worries, if your schedule made the cone bend properly it fired to that cone. It’s a near sure fire way to tell. As to bisque schedules they are longer and slower to burn out organics etc.... not all clays need to go that slow and long. It’s a matter of experience and trial and error for many clays. Again a witness cone to 04 will tell you with near certainty your schedule worked. And yes when your schedule achieves the temperature you programmed it for, it should switch the heating part of the kiln off. People slow cool or power cool to grow crystals or increase the matte look of their glaze. True matte glazes will be matte by formulation and will not need any special cooling to be matte. In general to get your schedules and cones to bend for you, the last 100 c of the firing needs to go at the rate published in the Orton chart. Lots of folks will pick the center column so for instance from the chart, 1222c (60c/hr) minus 100c = 1122c. My last segment starts at 1122c is set for 60c per hr. and ends at 1222. (Metric folks have it so easy!) Same for any cone you want to hit. Important part is the last 100c of the firing. PDF of imperial and metric Orton chart you can download for your own. http://www.sheffield-pottery.com/v/vspfiles/downloadables/cone_wall_chart_horiz.pdf Link to comment Share on other sites More sharing options...
Danny Posted May 23, 2020 Author Report Share Posted May 23, 2020 I'm so grateful for your replys, im starting to understand the firing process alot better now! Unfortunately my kiln continuosly runs for only 8 hours, so I will have to adjust the bisque firing schedule. I'm wondering if the cones bent has they should then surely the clay has vitrified. So much to learn about the firing process! The schedule I have worked out for bisque is 5hrs to reach 600, 2 hrs to reach 960, 1 hr to reach 1060 Link to comment Share on other sites More sharing options...
Bill Kielb Posted May 24, 2020 Report Share Posted May 24, 2020 6 hours ago, Danny said: I'm so grateful for your replys, im starting to understand the firing process alot better now! Unfortunately my kiln continuosly runs for only 8 hours, so I will have to adjust the bisque firing schedule. I'm wondering if the cones bent has they should then surely the clay has vitrified. So much to learn about the firing process! The schedule I have worked out for bisque is 5hrs to reach 600, 2 hrs to reach 960, 1 hr to reach 1060 For bisque If your clay is fairly clean and does not have a lot of organics to burnout And your wares are small, your eight hour schedule may be fine. Your final segment is 100c per hour so your finish temp likely should be about 1070c interpolating between 1063c and 1077c to account for the 100c degree per hour speed you have presently programmed. Cones would tell for sure so add an 05,04,03 cone pack (Guide, Fire, Guard) next time to get an idea. If you start having trouble with your glazes, many pinholes, carbon, etc... you may have to come up with a way to bisque fire longer, to remove all the contaminants in your clay slowly. Maybe, two firings one after the other sequentially. Maybe break up your schedule into an eight hour followed immediately by a four hour but use the Orton chart and the correct firing rate in the last 100c to get close to your desired cone. For glaze firings, no problem finishing in eight hours or less, just use the 60c degree per hour column for the last 100c degrees to get your desired cone to bend. Here is a comforting thought that may simplify things, cause this is really simple depending on whose teaching. Cones are made of glaze so when they have melted, the proper amount of heatwork has been done for that cone value. Very simple accurate way to confirm and repeat the same amount of heatwork. So if the cones bend properly, then yes you did the right amount of work ..... so ..... clay and glazes designed for that cone value were fired to their maturity. Link to comment Share on other sites More sharing options...
Danny Posted May 24, 2020 Author Report Share Posted May 24, 2020 This makes so much sense now, i will be printing out your comments and keeping them with my notes. I feel pretty excited to use the kiln now! Ive put a glaze firing in following one of the schedules using the 60c per hour for the last 100c degrees, using the cones so fingers crossed. The bisque may be trial and error but I will take your advice, thank you! Link to comment Share on other sites More sharing options...
Jessie2 Posted August 28, 2021 Report Share Posted August 28, 2021 On 5/23/2020 at 6:48 AM, Bill Kielb said: Here is a basic schedule below. Bisque firings generally take the most time so everything is burned out completely and slowly. Glaze firings are generally much quicker. The medium fire schedules below are probably most common. The important part of the glaze firing occurs in approx. the last 100c or 200F. This ramp speed should be set per the Orton cone chart to reasonably get the wares fired to the cone picked. Using firing cones will confirm what your wares were fired to. The schedules below are popular, you will need to convert them to Celsius. I would suggest trying first the slow bisque to 04 (13 hrs 26 minutes) and the medium glaze cone 6( 7 hrs 37 min) Verify each with witness cones so you know what it fired to. Finally let them cool at their own speed until you understand what slow cooling does for you. So when the firing is done, everything gets shut off and cools on its own, unpowered. Hi Bill! I wanted to ask, do you preheat or hold anywhere for these? I am new as well and trying to figure out where to begin!! Thank you so much! Link to comment Share on other sites More sharing options...
Bill Kielb Posted August 28, 2021 Report Share Posted August 28, 2021 6 minutes ago, Jessie2 said: Hi Bill! I wanted to ask, do you preheat or hold anywhere for these? I am new as well and trying to figure out where to begin!! Thank you so much! Generally preheats are to remove water slowly ensuring the liquid water does not turn to steam which shatters things. So if a piece is not thoroughly dry it’s quite common to use a preheat in their schedule. Folks who do heavy work such as sculpture also commonly use a preheat as they realize very heavy or thick work often will take a very long time to dry in regular room conditions. Aside from that, I really don’t have preheats or holds in my bisque schedules, but there are certain clays where the manufacture recommend additional time or a hold to burn out excess organics. For the most part, a slow enough rate to bisque in 10-12 hours seems adequate for many clays. Link to comment Share on other sites More sharing options...
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