Melt down

[spindy]

My clay dried out in the pouring table. We added water to get the specific gravity to 1.75 and also added a casting thinner. The older kiln sitter shut down come times throughout the night. The kiln may have been on high for 7 hours. Today we looked in and everything melted as flat as a pancake. Do you think we had a kiln sitter malfunction or poor clay chemistry. I am hoping to take a new piece to a friend to fire but don't want to ruin their kiln.

[liambesaw]

I think you fired low fire casting slip to mid fire.  What cone is the casting slip and what cone did you fire to?

[spindy]

Slip was low fire and used cone 04 in the sitter. I think the sitter failed.

[Min]

1 hour ago, spindy said:

I am hoping to take a new piece to a friend to fire but don't want to ruin their kiln.

Fire it on a waster. What did your cones look like? Also, if your casting slip dries out you don't need to add more deflocculant (casting thinner as you called it). This won't have evaporated, just the water in the slip. 

[Pres]

If you used the correct cones for the clay, and everything else checks out; I would ask if you have a sectional kiln?  Does the setter sit over two sections of this kiln? If so the setter may be off of 90 degrees perpendicular to the floor. Happens at times. 

 

best,

Pres

[Babs]

Can't walk away from a kiln and hope everything works every time.

Horrible lesson.

If sitter cone looks normal something is wrong with your body.

It is possible the cut off flap needs adjusting so it falls when cone bends.

The rod itself may be getting too thin.

I'd invest in a seperate timer set at approx 15-30 mins after expectex length of firing which shuts off power supply.

Or set a wake up alarm to go off 30min prior to kiln finishing.

I wouldn't put dicky stuff in friend's kiln.