How Long Should I "hold" My Skutt Kiln, While At The Highest Temp?

[Marge]

I have a Skutt with a kiln master controller. I've been firing to cone 6, but my cone (which I stick on my bottom shelf) is not bending to the correct angle. I think my glazes are not firing to their full potential. I'd like to make the kiln hold at the highest temp, but not sure how long. I read somewhere 20 min, but that seems like a long time. I have a bunch of test tiles and don't want to waste them...

Thanks a bunch!

Margie

[Bob Coyle]

Youn are going to have to experiment. there is no answer that fits all glaze situations. Try a 10-20 min hold .at the top of the ramp. Watch the cones through the peep hole then use the same ramp and hold that gives youn the best results.

 

The bottom shelf will most always be cooler than the top. You should be able to live with half a cone difference or use another glaze.

[Min]

To help even out the temperature in the kiln, when loading your kiln put less mass in the cooler area. Put your taller pots there so there are more elements between shelves. If the middle of the kiln gets hottest then put your shallow pots there with the shelves closer together. I agree with Bob that you are going to have to experiment, put cones on all shelves, not just the shelves that have peeps until you know your kiln temp inconsistencies. 

 

Min

[clay lover]

Min, that can be hard to do, if the thermocouple is in the center, it requires 2" above and below clearance, at minimum.  I also have the Skutt, 1027, and have worked hard to get semi even firings.

Try bottom posts no shorter than 4" and use 1/2 shelves in the top 2/3s of the kiln.  I use a slowdown from 2000* up to the peak, which will vary from kiln to kiln.  Remember, soaking bends cones just as much as the top temp does.   Sorry, but you will have to experiment around with the right combo of rise, temp and soak.  A 20 min. soak is good for glaze development and evenness of temp through the kiln,  Do you have "Mastering ^6 Glazes" ?  Good ^6 book to own.

Seems like they say last 200 *s, 120* per hour, temp 2200* soak 25 min.  That makes a ^7 in my kiln, so I fiddled with different things through many firings.  Remember to only change one thing per firing when you experiment, so you will know which change produced which effect.  I know, seems like it will take forever. 

And just about the time you get it all worked out, the elements get some age on them, start firing hotter, and you get to do it all over again, but with some experience and with smaller adjustments !

[Min]

With all due respect clay lover I disagree about needing a minimum of 2" clearance of shelves above and below thermocouple. From Laguna: "Keep kiln shelves and ware 1/2" away from thermocouple" A link to their pyrometer pdf is http://www.lagunaclay.com/support/pdf/Type_K_Thermocouple_Tips.pdf

 

I agree that the final temp rise should slow down, I rise my temp by 108F for the last 200 degrees plus I soak for 20 mins at 2115 if I am going for ^6 tip touching.

 

Min

 

edit: sorry typo, i soak starting at 2215 

[Wyndham]

If this is a newer controller, it should be able to be a  3 zone controller if you add 2 more thermocouples, one above one below. Check with Skutt for placement and installation. Thermocouples will price out around $30-$50 ea and are not hard to install.

 

A 3 zone controller will even out the heat at the bottom and top but may take some learning to get the full benefit. and this maybe something for the future as you gain experience with the kiln

 

Wyndham

[neilestrick]

Most manufacturers recommend 2" clearance around the thermocouple.

[Marcia Selsor]

If you are holding for the glaze to to "pop" by holding , go for at least 20 minutes. I have friends who hold for 2 hours when firing certain glazes like iron reds in the electric kiln.

 

Marcia

[clay lover]

It is really odd how different the same size and brand kiln can fire.  Min, if I fired your schedule, I would not make ^5.  I go to 2195 with a 20 min soak for a solid ^6.

[Min]

It is really odd how different the same size and brand kiln can fire.  Min, if I fired your schedule, I would not make ^5.  I go to 2195 with a 20 min soak for a solid ^6.

 

sorry, I did a typo, I start soak at 2215

[Chris Throws Pots]

Marge,

 

I hold for 5 minutes at 2215F then run a controlled cool at 200F/Hour down to 2115F (35 minutes combined hold and controlled cool). I am firing a Skutt 1231PK (1 thermo) and get very pretty even results with ^6 down and ^7 bending. 

 

Everyone has their own tricks and figures out the quirks of their own kiln. This works for me. Maybe it will for you too.

 

Cheers,

 

Chris

[Guest JBaymore]

Hold the kiln for the amount of time that gives you the results you want.  It is THAT simple. 

 

How do you know?  By producing a lot of work and firing a lot of work.  What is working for others is not necessarily going to work for you with your forming methods, your glazes, your glaze application methods, your stacking and firing process, your kiln unit, and so on.

 

Learn WHY things are happening... then you can apply that understanding to your OWN circumstances.  When making cookies, rather than just knowing to add a cup of sugar to the recipe because someone said to do that, learn what sugar will DO in cookie recipes and you can fine tune the sugar to get the cookies exactly the way you want.

 

This takes work.  You learn from working. 

 

best,

 

.......................john

[Karen B]

A mention to Marcia about holding for iron red glazes. The long hold is on the cool down in the 1600 range.