Running a mostly-empty kiln?

[PLN]

I know running a mostly empty kiln is not recommended because of uneven heating, wear-and-tear on the elements, and electrical costs.  

But I have spare elements and my electricity is free because I have an an oversize photovoltaic array where I live.    And I want to be able to run experiments and also I do intricate hand-built work that takes a long time to make, and not wheel pottery where I have much volume.     So are there ways I can run a mostly empty kiln, say by filling the unused volume with already-fired "scrap" pieces, or bricks to even out the heat distribution?  Thanks in advance.  

 

PS - Kiln is a Skutt  KM-822   (18" dia. , 22" deep)

Edited August 10 by PLN
supply kiln size info

[Bill Kielb]

Hmm, my experience and from an energy use perspective, your mostly empty kiln will generally fire faster than a full kiln, so adding things to heat consumes more energy in reality. For even firing, fire at slower speeds, but only if uneven.  Many electronic kilns fire fairly even already though, especially zoned kilns so again the dilemma to fire full may not really be there. Now, cooling a full kiln will cool at a much slower rate than an empty kiln. Slower cooling can have an effect on glaze appearance. Folks with small or empty kilns and electronic controls usually can choose to  down fire to emulate the slow cooling of a larger or filled kiln to get the same look.

So adding things to your kiln may not be necessary, especially if you have an electronic control. Your solar array will be happier as well and can continue to offset your HVAC, lighting, etc…

So do you need to worry about firing an empty kiln? Not really, with electronic controllers you can usually fire pretty evenly and emulate larger or more filled kilns when necessary.

Edited August 10 by Bill Kielb

[GEP]

From the situation you have described, I think it’s totally fine for you to fire almost empty loads. My only concern is something Bill mentioned, which is that your kiln will cool rapidly and that might not be something you want. If needed, this can be controlled with a digital kiln controller.

I’m a production potter with 7 cubic ft kilns, and of course I want them to be full, but on a regular basis I will fire half full, or nearly empty loads. Circumstances often don’t align for a full load! 

[neilestrick]

No need to put anything else in the kiln. That'll just use more power. With a single zone kiln like yours, put the bulk of the work in the center (vertically) of the kiln where the thermocouple is located, and put everything else as close to the center as you can. In a multi-zone kiln you want to spread the work out fairly evenly.