Seeking cone 5/6 electric kiln drop-and-soak and slow-cool firing schedules

[JRW 2]

Hi All,

 

I am having consistent trouble with blistering in my work. I have done a lot of research about how to troubleshoot this, and one of the solutions I have come across is doing a drop-and-soak firing. I am new to doing my own firings and to programming my kiln rather than using the pre-programmed schedules, but I tried the C6DHSC firing schedule.  The result was pretty terrible. Glaze ran and pooled, blistered, and darkened. Clearly everything was over-fired, and it didn't even help with the blistering! In fact I now realized it may have made it worse. I’m using a Skutt electric kiln with the Kiln Master controller.

 

Some of the glazes I'm using do better at cone 5,  so I'm trying to find a full program/script that will both (1)  help heal pinholes/blisters and (2) have a slow cool for better glaze outcomes (I've heard this is almost universally better than a natural cool). I know so much of this depends of the glaze and clay body. I am using Laguna S956 White Stoneware casting slip and various commercial glazes, mostly from the Amaco Potter's Choice  series. If anyone is willing to direct me to the full programming schedule for something like this I would be very grateful!

Edited Tuesday at 03:30 AM by JRW

[Hulk 866]

Hi JRW!

Can't help you with your program, however, I'd like to suggest you identify your controller make and model - perhaps someone with the same setup can help.

My kiln is manual - three switches for three zones, each with low, mid, high selection. I'm working with mid fire clays and glazes - started out looking to bend cone 6 cones full over, and have adjusted to cone 5 as well. I'm switching to low when peak temp is reached (no hold) until 100F drop, then twiddling the switches for a full hour to hold there, then I'm going back to low until drop to 1850F, when I'm shutting down and turning off the kiln vent as well. Once the temp has dropped well below 1000F, I'll turn the kiln vent back on if I'm looking to get a look sooner...

[Min 3,617]

Are you using cones to verify what the kiln reached? Post some pictures of the glaze issues with and without the drop/hold schedule.

On 4/5/2021 at 10:05 AM, JRW said:

Some of the glazes I'm using do better at cone 5,  so I'm trying to find a full program/script that will both (1)  help heal pinholes/blisters and (2) have a slow cool for better glaze outcomes (I've heard this is almost universally better than a natural cool)

Does you kiln fire evenly? If the top or bottom runs cooler you could load the glazes that do better at ^5 in those areas. Not all glazes benefit from a slow cool, generally speaking clear gloss glazes or glazes without visual texture won't look any different with a fast or slow cool.  Where slow cooling is really beneficial is with alkaline earth mattes (glazes that rely on high amounts of magnesium, calcium, strontium, barium (not recommended for functional ware) or zinc). If your commercial glazes don't look any different with or without a slow cool there is no point doing one. I do find a drop and soak/hold is beneficial for pinholes.