Ack! Medium Fire Not An Option - Question/help Needed

[Stone Spiral]

I spent the evening carefully loading my kiln. I went to start my Medium Ramp Cone 6 Glaze Fire - and the button for "medium" ramp is sticking/not working! I can only choose slow or fast ramp presets, until I can get it fixed/looked at. In the meantime, I do have to get this firing done as there are time sensitive pieces inside.

I have been doing some research on how that will change the glazes, and I am feeling a bit stuck.

Some people say a fast ramp with hold time and/or slow cooling, will produce nice results.

The Skutt website specifically says fast ramp is only for decals and lusters, and that glazes should only be fired slow or medium ramp.

I am concerned that a slow ramp to cone 6 may use a lot of power/be expensive.

I am concerned that a fast ramp to cone 6 may cause problems in the glaze - or alter it significantly? I would add a 5 minute hold to even out the kiln, and perhaps a slow cool?

 

This is unfortunate because my kiln is loaded with 100 test tiles (so how I fire this load will probably be how I will want to fire in the future) and also, quite a bit of student work.

 

I do slow ramp bisque firings. I have only ever glaze fired using Medium Ramp to Cone 6 (the preset)

Changing that feels scary!!

 

Advice?

 

 

Edited to add: This particular load is mostly commercial glazes. There are some homemade glazes in there, however most of the items have a cone 5/6 Spectrum or Laguna glaze on them. I don't know how the slow or fast ramp will effect these glazes.

[MatthewV]

You can use a program fire and make your own "medium" program.

The "medium fire" program is even on the second page of this:

http://skutt.com/pdf/op_manual/2009_op_manual/KM_Manual-09_Programming.pg17.pdf

 

for step 5 you could use the cone table to make it 5 or 6 with the hold you normally use.

[neilestrick]

Exactly. Just program a Ramp/Hold with the same steps as the medium fire program.

 

Firing on slow instead of medium will only cost a dollar or two more per firing.

 

In my experience, when controller buttons stop responding it's time to replace the controller.  It's not usually worth the money to have them repaired. Did you try unplugging the kiln to reset it?

[Stone Spiral]

Exactly. Just program a Ramp/Hold with the same steps as the medium fire program.

 

Firing on slow instead of medium will only cost a dollar or two more per firing.

 

In my experience, when controller buttons stop responding it's time to replace the controller.  It's not usually worth the money to have them repaired. Did you try unplugging the kiln to reset it?

 

Yes, I did unplug it. I unplugged it and left it for a while to reboot. When plugged back it, it is still programmed with my last firing - a slow bisque.

 

I know this kiln is older - I am the third owner. It has been moved around a few times and it starting to show some wear and tear. I guess this is a clue that I should start saving for a new one...

 

 

You can use a program fire and make your own "medium" program.

The "medium fire" program is even on the second page of this:

http://skutt.com/pdf/op_manual/2009_op_manual/KM_Manual-09_Programming.pg17.pdf

 

for step 5 you could use the cone table to make it 5 or 6 with the hold you normally use.

 

It seems so straightforward, but programming a manual glaze schedule seems so scary to me. I think I can do it. So I would use that chart on page 2, but on the final step, put in 2232F?

 

Does it really make a difference what speed you ramp at, if the ware is already bisqued?

[neilestrick]

Yes, the ramp speed in the final 200 degrees is what determines the final temperature for any given cone. So that's very important. Below that it's not such an issue, however you don't want to fire too quickly and crack your pots.

 

For the final 200 degrees of your firing put in 180F/hr, with a temp of 2232F. That'll get you cone 6.

[Min]

I would use 108F for the last 200 degrees of firing with top temperature being 2232F if there is no soak or just a very short (like 5 minute) one. Slowing down the firing at the end gives both clay and glaze time to mature. I would also put cones in front of each spyhole and monitor those towards the end of the firing.