How Much Does It Cost to Fire My
What Temperature Should I Fire My
I Am In a Hurry Can I Use the Fast
Speed in ConeFire Mode?
Can I Fire My Bisque and Glaze
in One Firing?
Do I Have to Be There While the
Kiln is Firing?
Can I Fuse Glass in My Ceramic
Can I Use My Kiln to Dry the
What is the Purpose of a Hold
Time in ConeFire Mode?
How Much Can
Fit in My Kiln?
Much Does It Cost to Fire My Kiln?
It is good business to know your costs. Firing costs have always
been somewhat of a mystery to many ceramic artists. While there
are many variables that can affect the cost, the calculation is
actually fairly easy. The new Skutt controller will actually
calculate it for you after each firing and if you have KilnLink,
it will automatically store those costs on your own personal
page. If you are working with an older kiln and do not
have this feature you can easily calculate it using this
KW Rating of Kiln x Length of Firing (Hours) x $/KW/Hr x
Adjustment Factor = Cost of Firing
Example: KM1231PK 208V 1 PH kiln firing a Medium Speed ConeFire
Mode Program to Cone 6 using a USA average electrical rate of
$0.12 KW/Hr and a load 100 lbs in the kiln.
16.64 x 8.47 x .12 x .5 = $8.45
So $8.45 to fire one of our largest kilns with a full load to
CONE 6! A lot less than most people think. A model 818 fired to
Cone 06 was only $2.83. Now I know that a lot of you are pretty
observant and are going “hey. what is this mysterious Adjustment
Factor?” In order to better understand this we need to look a
little closer at all of the variables individually. You will see
why this number is a sort of best guess due to the variability
This one is pretty straight forward. If you look on the serial
plate on your control box one of the pieces of data is the
Wattage rating of the kiln. This is the amount of energy that
particular model uses when it is brand new and on 100% of the
time for 1 hour. Since you are charged in Kilowatt hours, and
this number on the control box is listed in wattage hours, you
need to divide this number by 1000 before plugging it into the
As your elements age they lose some of their power so this
number will slowly drop as your elements age. This number is
also based on having the exact voltage of the rating of the kiln
available, under load (while kiln is on), during the entire
firing. The odds of this happening is pretty slim, but if you
installed the kiln correctly, it should be close. Here are some
of the things that can affect your wattage:
Low Voltage Caused by Undersized Wire or Undersized Transformer
(you live at the end of a country road)
Low Voltage Caused by Over Use of the Power Grid (everyone using
their air conditioning on a hot summer day)
Worn Out Elements
There are many things that can affect the time amount of time it
takes your kiln to fire a particular program. The good news is
that the kiln keeps track of this and tells you how long it took
after every firing. You will notice that this number will vary.
Just because you tell the kiln to follow a particular program,
does not mean it is capable of following the program throughout
the entire firing. Because of this, the firing times will vary
on the same program. Here are a few things that can affect your
The Size of the Kiln Load
The Temperature You Are Firing To
The Temperature of the Kiln Room
Price of Electricity
The cost of electricity varies all over the nation. It is
usually affected by the amount of locally generated power
available to a given population. Because some areas have less
than power than they would like, they ration it out by charging
different rates based on when you use it or what type of
consumer you are. You may want to see if you get lower rates if
you fire at night. If you are estimating the cost of firing your
kiln in a commercial building, be sure to use the rate listed on
the businesses energy bill and not your one at home. Rates can
vary between $0.08 (Washington) and $0.38 (Hawaii) per kilowatt
hour with the USA average being at $0.12/KW/HR for residential
and $0.10 for commercial.
The nice thing about the new Cost calculation feature in the new
KilnMaster Controller (manufactured after July 2012), is that it
actually calculates how long the elements are actually on. As
you probably know from hearing the relays clicking, they cycle
on and off to achieve the correct firing rate. The frequency of
this cycling will depend on the program entered and the ability
of the kiln to follow the program entered. Programs that have
fast firing rates or that approach the maximum temperature
rating of the kiln will generally require the relays to stay on
longer. Conversely, programs with extended hold times will
require less “on time” for the relays. Obviously when your
relays shut off power to the elements, you are not incurring any
cost so this “off time” needs to be accounted for. We have found
that a good estimate, across the range of ConeFire Mode
programs, is 50%.
What Temperature Should I
Fire My Bisque?
If you are using low fire clay and glazes and want some good
advice on what temperature to fire your bisque, read this
article by Artist/Instructor David Gamble
is a great article by David Gamble talking about bisque.
I Am In a Hurry..Can I Use
the Fast Speed in ConeFire Mode?
NO!!!!!!!!!!! Ok..sorry for yelling. The Fast speed is just for
lower temperature firings like Decals and Lusters. Now it is
true that Potters have used the fast firing speed and have
gotten away with it…but…is it really worth the risk to save a
Just think of how awful you would feel opening your kiln to find
shards of ceramic pieces on the shelf. Then you have to clean
out the whole kiln, and if pieces got on the elements and
melted, you have to order new elements.
Stick with Slow for Bisque and Medium for Glaze firings and
reduce your stress levels.
Can I Fire My Bisque and
Glaze in One Firing?
This is done in industry and by experienced high fire potters.
You may have heard the term “Monocotura” if you ever shopped for
tile. This is an Italian term that literally means single fired.
It generally is considered to be higher quality because the
glaze bonds better to the clay. This works in industry because
they have Ceramic Engineers controlling every step of the
process from materials selection to glaze application to the
firing process. In a studio setting, it could spell disaster.
You will more than likely end up with a lot of glaze defects
like pin holing. If something is going to blow up in the kiln,
it is almost always going to happen during a bisque fire.
Wouldn’t you rather this happen before you have glazed the
Do I Have to Be There While
the Kiln is Firing?
Ultimately this is your decision to make. All manufacturers
recommend that you are present when the kiln is scheduled to
shut off. This is to make sure the kiln shuts off as expected to
protect your ware and the interior of your kiln. Kilns are meant
to contain heat so fire is not the issue. I don’t think you sit
around and watch your furnace all night so why would you watch
your kiln. Anyway, if your kiln is electrically sound (just like
any other electrical machine, the room is secure from children
and pets, and there is no combustible material in the room that
is going to be blown against the kiln, it should be fine. If you
want the piece of mind of being able to monitor your kiln from
your smart phone check out KilnLink.
Can I Fuse Glass in My
As a matter of fact you can. For years it was believed that
glass could only be fused in a kiln with elements in the lid.
Artists worried that if you tried to fuse glass in a side-fired
kiln the temperature difference between the edges of the glass
near the elements, and the center of the glass would become to
great and the piece would crack. We then found out that if you
slow your firing program down you can keep this temperature
difference to a minimum and the fused pieces came out just fine.
When you fuse in a side fired kiln you have the advantage of
being able to load pieces on multiple layers so you can fire an
entire class’s projects at one time. Take a look at this article
that tells you how to load and program your kilns for glass.
Glass in Your Ceramic Kiln
Can I Use My Kiln to Dry
the Greenware Faster?
NO! Sorry, there I go yelling again. We are just trying to help
you make your kiln last longer. The fact is, your kiln hates
moisture. The moisture from the clay attacks anything that is
metal in your kiln. This includes your bands, elements,
thermocouple and hardware. If your kiln was made within the past
10 years you will notice the first question it asked you when
you are programming is “How long do you want to Preheat?”. The
Preheat feature is to be used to ensure small amounts of
moisture left in the greenware is drawn out before the kiln
reaches temperatures high enough to make cause the moisture to
turn to steam and potentially damage the piece as it is
released. A good rule of thumb is to hold the greenware up to
your cheek. If it is cool, it still has moisture in it. If it is
room temperature it is ready to be loaded.
What is the Purpose of a
Hold Time in ConeFire Mode?
When you are entering a ConeFire program the last question it
asked you is how long do you want to hold at peak temperature? A
hold time can serve several purposes. probably the most
important function of a hold time is to allow the kiln time to
"balance out". If a kiln is loaded denser in a particular part
of the kiln it can take a little longer for those pieces to
reach temperature. A 5 minute hold time can give those pieces
that are lagging behind time to catch up with the rest of the
kiln and therefore "balance out". Remember, that a 5 minute hold
is entered 00.05 not 05.00 (like your microwave). I 5 hour hold
could ruin all of the pieces in your kiln. We rarely recommend
entering a hold time in ConeFire Mode of more than 20 minutes.
How Much Can Fit in My
This is a very common question that is not easily answered. When
we are talking about kiln sizes, many factors come into play.
Since everybody creates different sized pieces, the answer can
vary from individual to individual. The best answer that we have
found is in the PDF link below in David Gamble's "How Big is
Big is That Kiln PDF?