Cone 6 firing schedule for SCM etc glazes

[June Perry]

I spent the past few days throwing a large amount of test tiles using 3 different cone 6 bodies to test both in cone 6 oxidation and soda. Can someone please share their cone 6 oxidation schedule for me to test both the SH glazes and my own cone 6 calcium matts and other glazes.

Stevens higher cone firing schedule is on his page, but not the cone 6. From what I have garnered reading some messages on the group, the schedule is  6 to cone 6 1/2, hold 1 hr, fast drop to 1600. Is there a hold at 1600? Also, is this the correct schedule? My tiny test kilns are manual and my bisque electric kiln is pretty big, so I don't want to waste all the work throwing, trimming and glazing around 100 tiles for the C6 ox firing, by not using the right firing schedule.

 

Thanks for any help!

June

http://www.shambhalapottery.com

http://www.shambhalapottery.blogspot.com

 

[Tracy Minarik]

Hi June ~

I have the schedule, but it's at the studio and it's only 8:30 am here...
I'll post it for you when I go into work today about 11:00.. If you haven't gotten it before that..

~ Tracy

[Karen]

I've been struggling with learning cone 6 oxidation glazes since buying my L&L last spring. I've been using the MC6 schedule but have some pinholing in the licorce recipe and would like to try another firing schedule (and try thinning the glazes.)  I was reading Steven Hill's article and thought I was missing something when I read that he cooled naturally to 1700 so I searched the Internet. Thanks for posting June!  How did the tests turn out?  I thought I'd first try the SH probably schedule for bisque from the OR newsletter.  

[June Perry]

You're welcome Karen! We tested some of them in soda but the kiln didn't get up to temperature, so when I can get around to it, I'll test them in my soda test kiln.

We're been dealing with a very serious health issue at our house, so I haven't even been able to get into the studio for 5 weeks or more.

Warmest regards,

June

[Karen]

I'm sorry to hear that June.  I send good thoughts and wishes for strength and healing of the health issues in your family. 

Karen

[June Perry]

Thanks Karen. It will be a while before I can get back to work - how long I don't know. My husband is very weak and can't be left alone. We're hoping that he will rebound from the result of his treatments but it is going to take a while for his strength to return.

June

[Donna Kat]

If you go to frogpondpottery.com you will see variations of the licorice glaze (called Ron's Black) and there is also one ones on masteringglazes.com that addressed crawling.  You can also try bisque firing higher.  You can also change the Whiting with Wollastonite (whiting causes pinholing).

[Tom Waggle]

http://ceramicartsdaily.org/firing-techniques/electric-kiln-firing/...

This has Steven Hill's firing schedule.

I purchased his video.  It is well worth the $50.  It has a thorough explanation of the method.  It also has his recipes.  Steven is very friendly and has sent me updated recipes as well as spent time talking on the phone with me with questions I have had.

He encourages you to try testing your current cone 6 glazes by spraying them over Strontium Crystal Magic to see what happens.

Contrary to what someone else commented it is not a slow fire.

Here is the schedule from his article in Ceramics Monthly:

RAMP 1: 200' F/hr. > 220'F  HOLD 1-3 HRS. depending on wetness of work

RAMP 2: 100' F/HR. > 500'F  HOLD: 0

RAMP 3: 400-500' F/HR .>2100'F  HOLD: 0

RAMP 4: 100'F > 2160- 2190'F HOLD for 30-60 minutes depending on kiln. This is Cone 5 and the hold will get you to Cone 6.  Test your kiln to find the correct hold time to achieve Cone 6.

RAMP 5: 9999'F /HR. >1700'F  This is for SKUTT kilns.  L&R should program 4000'F/HR.  HOLD: 0

RAMP 6: 50'F/HR. > 1600'F  HOLD 45-60 MINUTES

RAMP 7 50'F /HR. >1500'F HOLD: 0

I hope this helps.

[Brian Dean]

Steven Hills Cone 6 Firing Schedule

200F/hr(ramp) to 220, Hold=0

400F/hr(ramp) to 2100, Hold=0

100F/hr(ramp) to 2170, Hold=60 min

Freefall to 1700, Hold=0

50/hr(ramp) to 1600, Hold=60

50/hr(ramp) to 1500, Hold=0

Kiln Off and let cool naturally

Depending on Age of Kiln you might have to tweak schedule. Use Cone Packs to understand how your kiln is firing and what temps your particular kiln reaches using this schedule. Cone 6 cone should be down.

[Tom Waggle]

I think it is important to stress the hold at Cone 5, it will fall between 30 and 60 minutes, rather than a set "60 minutes", each kiln is different and newer kilns with better insulation will take shorter to reach Cone 6 during that hold.  Obviously using some cone packs (^5,6,7)during the test run/runs will help determine the appropriate hold  time (as Brian noted in his reply).

Also Steven does a single firing of his pieces, so the Hold at at Ramp 1 is critical for this.  IF you are firing work that has already been Bisque fired, then the hold at RAMP 1 is probably not necessary, though a short hold isn't a bad thing.

I just reprinted the information from the Steven Hill article.  I have used this schedule with great success.

To make that Freefall happen at RAMP five,  Skutt temp is 9999'F and L&R is 4000/Hr.

[Karen Totten]

Here's the schedule Steven posted on Facebook in 2010 right after he nailed it - don't know if he made any subsequent modifications or not...

"... briefly... cooled naturally to 1750, 50 an hour to 1600, 1 hour soak at 1600, 50 to 1500, then off. Pretty radical, but the micro crystalline glazes were spectacular!"

 

[Norm Stuart]

Karen - We normally use a 50F cooling between 1,800F and 1,500F, both with and without SCM. We lose the shiny poster-paint gloss which many ^6 glazes otherwise exhibit.

But we also get so much more crystallization that I need to add additional frit or other glass formers to typical ^6 glazes (used without SCM) to prevent them from "drying up" and turning matte during the crystallization.

I'm curious what is the main difference you see when you also hold at 1,600F for an hour? You say micro-crystalline formation, rather than macro-crystalline formation like the photo below. Or is this what you mean?

This is typical.  Clear Base Blue, glaze #39 on this webpage:

http://www.wpapotters.blogspot.com/2010/11/cone-6-oxidation-results...

Without a slow-cool, . . . with our slow-cool, . . . and finally the same glaze at our slow-cool with 10% 3269 Ferro Frit added.

Slow-cooling creates so much micro-crystallization that the shiny blue glaze becomes a matt brown. Adding frit enables the increased micro-crystallization to remain under a layer of glass - or at least that's my current explanation.

Karen Totten said:

Here's the schedule Steven posted on Facebook in 2010 right after he nailed it - don't know if he made any subsequent modifications or not...

"... briefly... cooled naturally to 1750, 50 an hour to 1600, 1 hour soak at 1600, 50 to 1500, then off. Pretty radical, but the micro crystalline glazes were spectacular!"