Kiln Comparison Plus Tips

Copyright © 2010 Tonya Davidson

  Dimensions Loading Max. Temp. Brick/Muffle Controller Travel Electrical Other
Fire Fly Inside
8"x8"x4"

Footprint
15"x18.5"x12"
Top loader w/ hinged lid
Fixed lid and base
2350°F Kiln Brick Digital pyrometer - not programmable Can travel in plastic bin Regular household current Lowest price!
Limiting height
Digital Fire Fly Inside
8"x8"x4"

Footprint
15"x18.5"x12"
Top loader w/ hinged lid
Fixed lid and base
2350°F Kiln Brick Fully Programmable Can travel in plastic bin Regular household current Great price!
Caldera without Collar Inside
8"x8"x6"

Footprint
13"x20"x14"
Top loader
The lid on the Caldera can be slid to one side allowing little heat to escape when loading or unloading. This can be a nice advantage.
2350°F Kiln Brick Programmable Can travel in plastic bin Regular household current Best bang for the buck!
Most versatile of all kilns!
Caldera with Collar

Bead Collar

Enameling Collar

Inside
8"x8"x6" or 8"x8"x10.75"


8"x8"x13.5"
Top loader
The lid on the Caldera can be slid to one side allowing little heat to escape when loading or unloading. This can be a nice advantage.
Bead door is tall enough that you can enamel throught it.

2000°F

Temp drops

No Elements in collar

1800°F

Kiln Brick Programmable Can travel in a plastic bin Regular household current The bead door is taller and wider than the SC with a Bead Door
Can enamel through bead collar!

The enameling collar door is taller than the bead door
Multimedia Series Inside
8.5"x12"x6" (12A)
8.5"x12"x9" (12T)

Footprint
14"x21"x18" (12A)
14"x21"x20" (12T)
Front Loader 2000°F Kiln Brick Programmable Can travel but heavy (75lbs) Regular household current
12T requires 5-20 plug to be installed by electrician
Amazing kiln that does many mediums great!
Xpress E Series Inside
8.5" x 9" x 4.5" (E9A)
8.5" x 9" x 8.75" (E10A)
13" x 13.5" x 8.75" (E14A)

Footprint
14" x 18" x 16.25"
18.25" x 22.5" x 20.5"
Front Loader 2000°F Kiln Brick Programmable Can travel Regular household current (except E14A is 240V) 4.5" height = E9A
8.75" height = E10A and E14A
SC Series Inside
8"x8"x6" (SC2)
8"x8"x8" (SC3)

Footprint
14"x14"x16"
Front Loader 2000°F Muffle Programmable Can travel - no extra packing needed Regular household current
  • 6" in height = SC2
  • 8" in height = SC3
  • Plain door
  • Door with window
  • Door with bead door
  • Door with window and bead door
Home Artist Inside
12"x12"x12"
Top Loader 2000°F Muffle Programmable Can travel on built-in luggage wheels Regular household current  

Tips

  • Test your kiln every 75 firings.
  • Vacuum out your kiln regularly (hepa filter is best).
  • Always protect the floor of your kiln with a shelf or fiber paper.
  • Fiber shelves sprayed with rigidizer (often referred to as Hard Fiber Shelves) are best for firing metal clay. Cordierite shelves are a heat sink and can create hot spots under your piece. They are not recommended for metal clay firings, by WLW or Paragon, but are perfect for glass and ceramics.
  • Solderite boards are not rated to be fired above 1700°F and they tend to thermal shock when exposed to cool air. They are great for torch firing, but not ideal for kiln firing.
  • Before firing glass, enamels or glazes take a slightly damp paper towel or sponge and wipe down the thermocouple (just the end protruding into the kiln). Every time you fire your kiln the thermocouple sheds a layer of metal, or oxidizes. This can be seen in the tiny black flecks in your kiln. These do not burn out and Murphy's Law says they'll land right in your glaze or enamel!
  • Place your kiln on a heat-proof surface and 6" away from flammable items (wall, boxes, etc.)
  • It's tempting, but try to keep from putting things on the top of your kiln. Your peep hole and vents need to be open during firing.

Kiln Operating Costs

To Figure Firing Costs of Operating the Kiln:

KW x Hours x Power Rate = Cost to Fire

  • KW: KW your kiln uses(keep in mind metal clay users are not using it at full power...but med)
  • Hours: Hours you fired (don't forget to count the time up to hold time - kiln will show this total time at end of firing)
  • Rate: Power rate (get from your bill)

For example:

1.44 (approx. for SC2) x 0.75 x 0.0937 = 0.10 (10 minute firing)
1.44 x 3 x 0.0937 = 0.41 (approx 2 hour firing at med. setting 1650°F)

Sample BronzClay firing (approximately):

1.8 x 7 x 0.0937 = $1.18 per load (4 hour firing held for 3 additional hours)

It is wise to consider the following wear and tear costs:

  • Shelves
  • Posts
  • Fiber Blanket, Vermiculite, etc.
  • Thermocouple life
  • Element replacement
  • Time to load and unload

Suggested Firing Schedule

We recommend that you watch the Video Tutorial on Programming Your Digital Kiln. Here are some basic programs that I personally use when firing:

Firing schedule for silver metal clay (this is the same temp for firing PMC3 onto ceramic glazes or bisque:

  • RA1 = Full Speed
  • Temp = 1650°F
  • Hold = 30 minutes to 1 hour
    I don't fire 2 hours as it's only 5% difference in strength between 10 minutes and 2 hours. However, due to inconsistencies in kiln firings I fire for a minimum of 30 minutes. If you have time, fire for 2 hours.

Firing schedule for BronzClay 3-4 cards thick:

  • RA1= Full Speed
  • Temp = 1190°F
  • Hold = 0
    If you have time, hold here for an hour.
  • RA2 = 250
  • Temp = 1490° (1516°F in a SC fiber wall kiln)
  • Hold = 2 hours
    3 hours for thicker pieces.

Firing schedule for glass with PMC or china shards with PMC:

  • RA1= Full Speed
    Unless the glass is bigger than a nickel or more than 1/4" thick
  • Temp - 1200
  • Hold = 35 to 60 minutes

Kiln Height — What height do you need?

6" in height allows you to fit 1-2 shelves. You'll want to purchase 2 pair of the 1" posts, 2 pair of the 2" posts, and 2 shelves. Unfortunately 6" is not tall enough for glass bracelet mandrels or even simple coffee mugs. In order to fit stilts and a shelf in the kiln when firing a mug you'll need the 8" or 10" kiln.

For more versatility we recommend the SC3 or Caldera with Collar.

 

Top Loading vs. Front Loading — What are you planning on firing?

Top loading kilns are easier to load. The tendency with a front loader is to only use the front 4". The heat sensor, or thermocouple, is actually at the back of the kiln. The front of your kiln tends to be cooler. Top loaders allow you to see work from a birds-eye view when placing it on the shelf. If you are only firing a few pieces, in a top loading, you can elevate your first shelf on 2" posts. This way you are firing in the center of the kiln.

If you are going to do a lot of enameling, for production purposes, it is going to be easier to have a front-loading door. However, you can certainly enamel in a top loader. Elevate the shelf near the top of the kiln on posts. You'll place your enameled piece, which is on a trivet, into the kiln using Big Tweezers (12"+) and heat-resistant gloves. You'll also remove it this way. This is no more difficult than working with a firing rack, firing fork, and trivet. It's just different and not shown in books.

You can successfully load enamels on jewelry-sized items through the bead door on the Caldera. The SC bead door is not tall enough to allow a trivet to pass through.

 

Kiln Brick vs Muffle/Fiber Type — What's it made of and why?

There is no truth to the wives tale that you cannot fire multiple mediums like metal clay, glass, ceramics and more all in the same kiln. There is no residue left as most items burn off by 1000°F. Also, there is no truth to any statements that it is better to fire metal clay in a fiber/muffle wall kiln over a kiln brick kiln. The new jewelry type kilns, such as the SC series and Evenheat kilns, were designed with the muffle-fiber walls as they heat and cool faster, the elements are not exposed, they are a bit more lightweight, and the white interior is more aesthetically pleasing.

When metal clay first came out these kilns were preferred as most weren’t combining mediums and we wanted a kiln that fired quickly and was lightweight.  These kilns were purchased by teachers and students alike, as the kiln to purchase for metal clay.   Many didn’t take the time to research and see if these kilns fit their multi-media needs.  As the industry grew so did the available kilns which better suit the metal clay artisan.

The fact remains that a kiln that has elements on 3 or 4 sides is better than one that only has elements on 2 sides (SC series). Glass, for example needs to have radiant heat in order to achieve temperature uniformity. Radiant heat is line of sight, not convection. Also, with a kiln that has kiln brick you are going to have stored thermal energy, thus it will retain the heat better. This means if you do multiple firings, you will be able to heat the kiln back up faster, and when opening the door to do enamels, your kiln will recover more quickly. This is why all kilns sold for the purpose of enameling are kiln brick. The Caldera and Fire Fly are very fast for a brick kiln because they are overpowered. So this offsets the concept that kiln brick kilns are slower to heat up.  Not to mention that a kiln with a digital controller is going to have a high level of precision in the firing process. The Xpress series and MultiMedia Kilns are the best of all worlds if you can afford it. Kiln brick, metal casing on entire kiln, programmable, front loader. All great things!

There also is no truth to the fact that moving the Caldera, Fire Fly or Xpress kilns can displace the elements. They are securely fitted in a track. Elements do expand and contract as they heat and cool. With larger kilns you can have elements that need to be re-pinned, but this isn't usually the case with the smaller kiln brick kilns. The kiln brick is more fragile than the muffle kilns. However, by simply getting a plastic bin, and handling with care you can transport these kilns adequately. However, the muffle kilns do not require as much care and can be placed in the trunk of your car without a box or bin. So if you are teaching a lot, then do get a muffle kiln. It is important to keep your kiln brick kiln elements clean with an occasional vacuuming. Excessive movement can cause the brick to chip and break off. Vacuuming your fiber wall kilns is also good for maintenance.

Another thing to consider is maintenance. Elements will go out between 5-10 years depending on use and how hot you fire your kiln. The closer you can get to the top rating the more wear and tear you put on the elements. The muffle type kilns cost $250 to replace the elements. Plus you'll most likely need to ship it back to the manufacturer for replacement ($350+). The elements in a kilns brick kiln are 5 times less to replace and you can either do that yourself or have it done locally.

BronzClay, Copper Clay and Glass Casting require slower firings.  This puts more strain on your kiln to ask it to hold for long periods at certain temperatures.  The relays in a kiln are responsible for allowing the current to flow through the contacts to the elements, which generates the heat.  Relays have a finite number of clicks.  The more clicks in a firing, the fewer firings it will produce.  As a kiln is asked to hold a temperature it must keep up with heat loss.  Heat is lost more readily in a muffle-type fiber kiln than a kiln-brick kiln.

Also the closer the relay is operated to its rated amps, the shorter its operational life.  This is why you don’t want to purchase a kiln that is rated to 1700°F if you are always firing to 1650°F.  Your kiln will need more maintenance.

For these reasons, we prefer to recommend a kiln-brick kiln unless you are traveling to teach often or need that extra 10 minutes it takes to heat up the kiln or the extra 20 to cool it down.  Your kiln will last longer, retain the heat better and give you a better firing overall.

 

Comparing the Paragon against Evenheat Kilns

Customer Service

Paragon has always handled all claims and concerns fairly and quickly with all of Whole Lotta Whimsy’s customers.  We switched to this manufacturer because of this reason.  They care about the customer and want them to have the best experience.  They also are a family-owned business that has been in business for 61 years.  You know you’ll be able to get parts in a decade when you need them.  They own the design of the kiln and are not just the manufacturer.

Water-Base Finish vs. Powder Coat

The finish on the Paragon kilns is perfectly durable is a high-heat water base finish. Paragon chose to use this coating for the safety of their employees and because it's better for the environment.

Angled Control vs. Flat Control

The flat control allows you to view the temperature easier from across the room. No worries about dropping anything on it when unloading or loading the kiln. The buttons also have no gaps so there is no worry about getting anything inside the panel.

Toggle vs. Rocker

There really is no difference between the rocker and the toggle. The toggle is a bit easier to turn off in an emergency. It doesn't stick out enough to get in the way of anything.

Programmable vs. Presets

Presets are unnecessary. They can also be very limiting if you cannot change them. Kilns are easy to program, and the programs are retained in memory until you change them. If you are interested in mixing media (enameling, ceramics, glass, etc.) you'll want a kiln without presets. None of our kilns come with presets.

Window

The window is not necessary, but useful for enameling and glass fusing. After some time you will be able to learn what you are looking at through the window, due to the orange glow. Don't forget to wear Shade 2 minimum glasses. You'll also have to play with the shelf height to have a good view of your work when it's firing.  The window is a great upgrade.

Bead Door

The bead door option is for annealing the glass when doing lampworked beads. Most glass beadmakers work on 9-12" mandrels which do not fit in an 8" kiln without a door (with the bead door the mandrels can stick out during annealing. You can always buy a replacement door for $100+ and drill the holes to install it later. However, if you think you might like to do glass beads, or you might sell your kiln later then add the bead door now. If you plan on making a lot of beads at one time the Caldera w/Bead Collar has a wider and taller door. It can fit in more beads.