Drop and Soak program for Cone 6 in Skutt

[Potpotpotter]

Hello everyone,

I have a skutt kiln with touch screen controller and I want to know how to add a hold and soak program in it for cone 6 to avoid pinholes and blisters. Does anybody have a program that worked from them that they can share please?

Thanks!

[Min]

There isn't a one size fits all firing schedule to fix pinholes and blisters but somewhere to start would be to drop 100F below your top temperature and hold there for 15 minutes. One other thing I do is for my kiln and my glazes it works to fire below the top temp and soak there to bring cone 6 down then do the drop and hold/soak, (I also do a slow cool for my satin matte glazes but that isn't necessary for many glazes). It can take a few firings to dial in what works for your kiln and glazes.

[Bill Kielb]

2 hours ago, Potpotpotter said:

Does anybody have a program that worked from them that they can share please?

As min mentioned above, but since you have a touch screen you could program a cone 5 auto fire, add a 15 min hold at the end to get to cone 6 heat work, then add your 100 degree drop (from cone 5 peak) and hold as something to start, tweak from there depending on results. This way the autofire can do most of the schedule firing for you.

Edited March 10 by Bill Kielb

[Potpotpotter]

3 hours ago, Bill Kielb said:

As min mentioned above, but since you have a touch screen you could program a cone 5 auto fire, add a 15 min hold at the end to get to cone 6 heat work, then add your 100 degree drop (from cone 5 peak) and hold as something to start, tweak from there depending on results. This way the autofire can do most of the schedule firing for you.

Thanks! I will try this. So the last segment will be for drop right? Sorry if I’m asking silly questions because I have not programmed it before.

[Bill Kielb]

38 minutes ago, Potpotpotter said:

. So the last segment will be for drop right?

Yes, I believe so. So for me, I would program cone fire to cone 5, a fifteen minute hold at cone five and a drop and hold or cooling segment. You may have to enable the cooling segment in advance

Edited March 10 by Bill Kielb

[Min]

@Potpotpotter, slow cooling is different from a drop and hold/soak. With slow cooling the preprogrammed slow cooling schedule will be something like 9999 (freefall) from the last temperature in the program down to 1900F then 150F down to 1500F. If a glaze is already a matte without this slow cooling then by adding one you could very well end up with it being far more matte. This schedule is a basic slow cool for functional glazes, many people do their own custom slow cool schedules to suit their glazes. Slow cooling promotes certain glaze characteristics such as micro (matte glazes) or macro glaze crystals or visual textures within the glaze. It helps with some glazes and does nothing for others. Slow cooling is also useful for large pieces to help prevent dunting/cracking. 

A drop and hold/soak is helpful to help heal pinholes and blisters. The temperature you hold at will depend on how fluid the glaze is at certain temperatures. There are many causes of glaze pinholes and blisters, glaze thickness, application, glaze chemistry,  bisque and glaze firing all can contribute to them.

 

[Dick White]

@Bill Kielb and @Potpotpotter The Skutt Touchscreen controller, while built by Bartlett to Skutt's specifications and similar in many ways to Bartlett's own Genesis, does not have the toggle to turn on the optional cooling segment as the final segment of a cone-fire (auto-fire) program. Such  a capability was available in the Skutt KM series kilns using the controller logic adapted from the Bartlett native V6-CF controllers, Skutt removed that from their Touchscreen version of the Bartlett Genesis. With a Skutt Touchscreen controller, one now must build a custom ramp-hold program that mimics whatever cone-fire program on the way up and then add one or two more steps at the end of the program for a controlled cool.

[Bill Kielb]

2 hours ago, Dick White said:

With a Skutt Touchscreen controller, one now must build a custom ramp-hold program that mimics whatever cone-fire program on the way up and then add one or two more steps at the end of the program for a controlled cool.

Yuck, what a pain! Good to know. @Potpotpotter pretty easy to build a schedule, the last 200-250 f is most important to get the right speed to bend cones predictably. If you are unsure tell us, this is easily solved.

[neilestrick]

On 3/11/2024 at 6:27 PM, Dick White said:

Skutt removed that from their Touchscreen version of the Bartlett Genesis. With a Skutt Touchscreen controller, one now must build a custom ramp-hold program that mimics whatever cone-fire program on the way up and then add one or two more steps at the end of the program for a controlled cool.

Does it have a 'copy' function like the Genesis, where you can copy the Cone Fire  schedule into a custom program?

[Potpotpotter]

Thank you everyone! I copied my cone 6 program and added a 5 min hold at cone 6, 

2230-2100 9999f/hr hold again for 15 mins

2100-1900 108f/hr hold again here for 5 mins and natural cooling after that.
This worked pretty well as I just found 1 odd pinhole on the outside of 1 mug.  
I recently heard For Flux Sake and the host advised bisque firing to cone 08 to avoid pinholes and blisters. I have never heard of this before and always thought that 04-06 was a pretty standard temperature for bisque firings.

[Potpotpotter]

On 3/11/2024 at 10:01 PM, Bill Kielb said:

Yuck, what a pain! Good to know. @Potpotpotter pretty easy to build a schedule, the last 200-250 f is most important to get the right speed to bend cones predictably. If you are unsure tell us, this is easily solved.

I was able to add a schedule right from scratch without copying but ended up copying the cone 6 and adding few holds while cooling.

[Dick White]

13 hours ago, neilestrick said:

Does it have a 'copy' function like the Genesis, where you can copy the Cone Fire  schedule into a custom program?

Dunno, I don't have a Skutt Touchscreen, and the "user manual" is a help screen embedded in the controller. All I know is what I hear from others who are struggling with it.

[Hulk]

...the host advised bisque firing to cone 08 to avoid pinholes and blisters."

Interesting!
I'm curious why, as I'd thought bisque firing higher, with extended hold(s) at lower temperature(s), and with continuous atmosphere exchange* was standard advice for burning off "...products of decomposition..."

Bisque (digitalfire.com)
"Bisquit should be fired as high as possible."
 

*via powered kiln vent, else convective scheme...

[Potpotpotter]

2 hours ago, Hulk said:

...the host advised bisque firing to cone 08 to avoid pinholes and blisters."

Interesting!
I'm curious why, as I'd thought bisque firing higher, with extended hold(s) at lower temperature(s), and with continuous atmosphere exchange* was standard advice for burning off "...products of decomposition..."

Bisque (digitalfire.com)
"Bisquit should be fired as high as possible."
 

*via powered kiln vent, else convective scheme...

The reason was that the high porosity leads to glaze sticking well without much (invisible) air bubbles. I’m doing a bad job explaining it, if you can listen to the podcast, it made sense technically but I have never heard of it before.

[Potpotpotter]

3 hours ago, Dick White said:

Dunno, I don't have a Skutt Touchscreen, and the "user manual" is a help screen embedded in the controller. All I know is what I hear from others who are struggling with it.

It lets you copy, you need to go till the last screen to get into temperatures to get that option.

[Dick White]

For Flux Sake is one of the offshoots from the inestimable Matt Katz, who in one of his webcasts long ago expressed an opinion that in addition to the usual list of pinhole suspects, poor application of the glaze was often a cause, particularly with brushed glazes. If the first coat of glaze had irregularities, those nooks and crannies could be covered by the next coat, leaving a tiny air pocket underneath. The problem is especially acute on textured surfaces. As the glaze melts during the firing, those little air pockets would rise to the surface and pop, leaving the pinhole. So, in Matt's opinion, pinholes could be from user error as well as decomposition of the glaze or outgassing from the body. Matt typically uses porcelain tiles for his testing, and bisques to 08 for consistent absorbency. A clean body such as porcelain does not need the higher bisque to burn out the organics and impurities.

[Morgan]

This is roughly the schedule I use (temps changed to get heat work where I want on my kiln)

https://digitalfire.com/schedule/plc6ds

then if you want you can use the same schedule with a controlled cool down if that’s your thing, for my glazes I prefer crash cool.