Jump to content

Recommended Posts

Hello, CeramicArtsDaily Community,

Been lurking around reading a lot of stuff here for the last few months and have a question that I haven't been able to quite get a clear grasp on.

I do ceramics as a hobby - mostly hand building but lately have not had any success in finding somewhere or someplace to fire my work. I do not have access to a kiln and have not been able to get my work fired lately so I've been researching, mostly waiting for a good deal, on small 120v "test" kilns, like the Paragon Caldera. A full-size kiln really isn't an option for me at all. For the type of work I do, I think these smaller kilns are almost perfect for me. I have done some researching on this site and see that a lot of you use those small test kilns as only a test kiln and not for production work. Is this because they do not fire as well as a regular sized kiln with venting, or for what reasons exactly is that? If you only had access to a small sized kiln, are there any good reasons why it could not or should not be used as your one and only kiln for work ranging up to cone 10 - which is important for me. 

I work in mostly earthenware for sculptural work and stoneware for functional work. Mostly everything is for personal use but if I had my own kiln I would certainly sell some work. 

Would a small 120v kiln such as a digital paragon caldera for sufficient for me or are full size kilns really the only way to make "professional production quality" work? 

Thank you in advance for any tips and help!

Share this post


Link to post
Share on other sites

hello, lurker!  nice to see you stop hiding.  the only reason i use a test kiln is that my large kiln has about a 23 x 27 inches interior.  and, being old and slow, i do not fire it regularly.  sometimes i just want to see what a glaze looks like when i change the color in a recipe or try applying it thicker.  so then i use a small paragon kiln i bought from a young man who inherited it from his mother.  she only used it to fire the heads and parts of dolls so it was barely used when i got it.  the elements look barely used.

if it were my only kiln, i would be severely limited in the size of work i could fire.  the kiln would be willing to be fired every day but its interior size is only about 12 x 12 inches.  that is very small for my stuff.  it would require me to change the sizes of my usual work so i could fit things in the tiny space.  as a test kiln, it is perfect.  if your work is tiny, it might be perfect for you as it was for it's original owner.

Share this post


Link to post
Share on other sites

not being a particularly fussy about the exact duplication of every firing and every glaze, it is OK for me.   my not educated guess has been that the clay, glaze and heat work are the same so it is fine by me.  if you are interested in the chemical composition of glazes and the minute changes that might arise, it would not be the same.

my big L&L has a digital controller but i only use the pre-set programs and the  preheat because i fire from greenware to glaze all at once in about a 12 hour firing.   occasionally i fire bisque to glaze and it is somewhat faster but i always choose the "slow glaze" setting.   i have never been interested in slow cooling or the like so i do not use the ramp feature.  

the small paragon can be connected to a digital controller on the wall but i have found that the sitter on the side of the kiln works just fine for my very limited needs.  it is small but it fires to cone 6.

Edited by oldlady
remembered preheat

Share this post


Link to post
Share on other sites

The smaller the kiln, the faster it cools, so the results from a baby test kiln will not look the same as from a larger kiln. To combat this, you need to do add in a slow cooling cycle to mimic the cooling rate of a larger kiln. Of course, if the small kiln is the only one you have, and you're happy with how the glazes look without the slow cooling, then it's not an an issue. But many glazes do not like being cooled very quickly. If you have a manual kiln, the slower cooling can be difficult, but it can be done.

The other reason to not use a small kiln for anything other than testing or the occasional small batch is that the cost per pot for firings is higher. As the kiln gets larger, the cost of firing per pot goes down.  You'll also wear out the elements much faster, and wear out the kiln much faster since you're firing it so many times. A little 0.5 cubic foot test kiln has to be fired 14 times as much as a 7 cubic foot kiln (the most popular size in the US) to produce the same amount of work (actually more, since larger kilns can be loaded more efficiently), so assuming the same number of firings in its lifespan, you'll need 14 times more baby kilns to produce the same amount of work as a 7 cubic foot kiln. Given that the large kiln does not cost 14 times as much as the baby kiln, it's much more expensive to use the baby kiln.

Share this post


Link to post
Share on other sites

arpetrone, i have just re-read your original post and realize that you might believe that many people on this forum have tiny test kilns that work on 110 or some such household current.

mine, at least, is an older very small paragon, i believe it is an A66.  it does NOT run on ordinary household current.   i hope you carefully read the disclaimer paragon has on the specifications for the caldera.  a kiln is not a toaster.

Share this post


Link to post
Share on other sites

If you buy a test kiln make sure you know the interior dimensions.   I  have a test kiln that will hold 6 inch square shelves,  I bought it for test tiles.    It cools so fast I have never been able to do a slow cool with it.  I have larger manual kilns that I do slow cools with so I am familiar with the technique.    When you buy one get the largest interior space you can find.    Denice

Share this post


Link to post
Share on other sites
On 4/1/2018 at 7:46 PM, neilestrick said:

The smaller the kiln, the faster it cools, so the results from a baby test kiln will not look the same as from a larger kiln. To combat this, you need to do add in a slow cooling cycle to mimic the cooling rate of a larger kiln. Of course, if the small kiln is the only one you have, and you're happy with how the glazes look without the slow cooling, then it's not an an issue. But many glazes do not like being cooled very quickly. If you have a manual kiln, the slower cooling can be difficult, but it can be done.

The other reason to not use a small kiln for anything other than testing or the occasional small batch is that the cost per pot for firings is higher. As the kiln gets larger, the cost of firing per pot goes down.  You'll also wear out the elements much faster, and wear out the kiln much faster since you're firing it so many times. A little 0.5 cubic foot test kiln has to be fired 14 times as much as a 7 cubic foot kiln (the most popular size in the US) to produce the same amount of work (actually more, since larger kilns can be loaded more efficiently), so assuming the same number of firings in its lifespan, you'll need 14 times more baby kilns to produce the same amount of work as a 7 cubic foot kiln. Given that the large kiln does not cost 14 times as much as the baby kiln, it's much more expensive to use the baby kiln.

Exactly the information I was looking for, thank you! It is a good point about wearing out the element/kiln faster than a regular sized kiln but there’s nothing to be done about that as a small kiln is really my only option at this time.

 

On 4/2/2018 at 12:20 AM, oldlady said:

arpetrone, i have just re-read your original post and realize that you might believe that many people on this forum have tiny test kilns that work on 110 or some such household current.

mine, at least, is an older very small paragon, i believe it is an A66.  it does NOT run on ordinary household current.   i hope you carefully read the disclaimer paragon has on the specifications for the caldera.  a kiln is not a toaster.

 

On 4/2/2018 at 9:28 AM, Denice said:

If you buy a test kiln make sure you know the interior dimensions.   I  have a test kiln that will hold 6 inch square shelves,  I bought it for test tiles.    It cools so fast I have never been able to do a slow cool with it.  I have larger manual kilns that I do slow cools with so I am familiar with the technique.    When you buy one get the largest interior space you can find.    Denice

Thank you both. I have and will do my research before buying the kiln as to what it can and needs to run on as well as the interior space.

Share this post


Link to post
Share on other sites

@arpetrone Many baby test kilns say they run on 'household' current, which means 110/120 volts. However most of them require a 20 amp circuit, which is not common in most homes outside of some kitchen outlets in newer homes, and possibly garage outlets. If the kiln pulls 15-18 amps, it needs a 20 amp circuit. Anything that pulls less than that won't be rated above cone 6 (or less).

Share this post


Link to post
Share on other sites

arpetone, i just looked again at the paragon caldera kiln and realized that you might be looking for info on a site that is NOT paragon industries kiln.  there is a distributor who uses the name paragon kilns and has a very nice website showing all kinds of current kilns.  

they are not the paragon industries manufacturer of kilns.    any info from a distributor could be less than you need to make a decision.  the true expert is howard arnold at paragon industries.

Share this post


Link to post
Share on other sites

I have a Crucible from Seattle Pottery about 20 years old. Much like this one from Seattle Pottery. I fore test for ^6 glazes to ^7 because it is fast and just uses a kiln sitter. I put a shed over the load inside  to slow down the cooling. 9 x11 interior. This one has a controller.

http://jenkenkilns.com/af3p-119w4flipdoor-1.aspx

Marcia

Share this post


Link to post
Share on other sites

I went to their website and looked at the manual for the caldera and the only thing I saw was that they stated was that the kiln should be plugged into its own appliance breaker and be the only thing used on that breaker while firing.

On bigceramicstore.com, they state the recommended breaker is 15 amps - which is luckily I standard if I’m not mistaken.

 

Edited by arpetrone

Share this post


Link to post
Share on other sites

That kiln is a 14 amp draw -for safety you need to have at least 10-20% extra so really thats a 20 amp breaker . The 15 amp breaker is not safe.The wire size needs to be #12 wire with a 20 amp breaker. My whole house is wired with 20 amp except the lighting circuits .To use that kiln especially at high temps a #12 wire with 20 amp breaker is what needed for safety .Sometimes info like that in charts is just wrong

Share this post


Link to post
Share on other sites

I would suggest giving Paragon a call, they built it and should be able to give you some guidance. I was instructed by Seattle pottery to swap out the wall receptacle with the one they provided. Ran it for 5-6 years with no issues in my garage. It may well have been a 20 amp breaker though. Sold the house and can't check. While very particular about such things on the larger stuff I just bought it on a lark at SPS while buying glaze materials and just followed their instructions of swapping out the plug and run it dedicated. It was such a small kiln that seemed fine so admittedly I did not check wire gauge and such.

Mines got an electronic controller to match its big brother, a 9 cf oval (also SPS).

http://www.seattlepotterysupply.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=sps_ecat&Category_Code=1IS

I've got the 12x13 interior one and it is small for things like bowls, mugs and such. With both shelves and 5" mugs I think you could fire 6 mugs and without the 2nd shelf fire 3-4 large and tall ones (no stilt for holding up shelf). Bowls, same deal one larger one and maybe 6 small ones as they can be 2 shelves. With the electronic controller it fires the same as the big one in my opinion. I use it to test glazes and my partner has used it for some small custom orders from time to time when firing out of sync with the two larger kilns. 

I was told it runs a couple bucks a load to fire. Since its about $10 (all northwest numbers) for the large one it is definitely more per pot but like you said, its your only option and still pretty cheap.

I personally would not go as small as that Caldera. That is just too tiny. The other one (AF3C) is closer to a 1cf and would stop there as far as going down in size unless you truly only want to ever fire very small items like beads. Besides the 1cf (12x12) is plenty small. I would recommend you measure out the dimensions on some paper or cardboard, account for 3 stilts holding up a shelf and 1/2" for shelf and at least 1/2" for top space from lid and 1" for floor shelf and space (you don't fire on the brick bottom).  Now put together a load on those shelves around marked off stilts with a 1/4" gap between each pot and 1/2" from edge using bowls, mugs and such. That's your load and it will take really the bulk of 24 hours to fill, fire and cool that load 2x's (bisque and glaze).

If you have a dryer plug you might also consider this:

http://www.bigceramicstore.com/bigceramicstore-com-biggest-little-kiln-3-key-digital-controller.html

 

Have fun!

Edited by Stephen

Share this post


Link to post
Share on other sites

Very interesting @Stephen, thanks for sharing. I hear you about the size of the Caldera, now that I think about it, it probably is too tiny. The 12x13 from Seattle Pottery Supply looks like a pretty sweet little and I would probably go for that no doubt if it fired to cone 10. Now I'm just as lost as I was in the beginning because I would like the option of firing to cone 10. 

That biggestlittlekiln isn't doing it for me for some reason though.

Good thing I'm not in a rush to get a kiln :huh:

EDIT: This is the one that would do it for me, I think.

http://www.bigceramicstore.com/cone-art-1813bx-electronic-model-bartlett-v6-cf-electronic-controller-16031.html 

But that price tag..

Edited by arpetrone

Share this post


Link to post
Share on other sites

arpetrone, did you check out the jenken that marcia mentioned?  yes, it is in florida but it only weighs 50 pounds if i remember from yesterday.

Share this post


Link to post
Share on other sites

@arpetrone there are very few good reasons to fire to cone 10 in an electric kiln. Almost anything you can do at cone 10, you can do at cone 6. If you are drawn to the look of cone 10 glazes, that look is due to the reduction atmosphere, not the temperature. At cone 10, the life of your elements goes down by about half, as does the life of the bricks. It's much more abusive to the kiln. However, you want a kiln that will go to cone 10 so that it's not struggling to get to 6.

Share this post


Link to post
Share on other sites

I didn’t check that Jenken out until you reminded me @oldlady. I think it’s a bit low fire for me, although thanks for the suggestion @Marcia Selsor.

So I’ve heard, about using a kiln to cone 10, @neilestrick but as you say, you do want the ability so as to not struggle going to 6. Not that I would even fire to c10 all the time. I think that cone art is my main interest now - if I can come to terms spending that much that is.

Another reason I want the option of cone 10 is because I have some brand new Sheffield 42 stoneware clay I haven’t even had a chance to put to use yet. It’s a c6-10 clay - would it still be vitrified/functional enough if only fired to c6?

https://www.sheffield-pottery.com/Sheffield-Moist-Clay-42-c6-10-50Lb-Box-Delivered-p/mc42fs.htm

I wouldn’t want to throw it out.

Edited by arpetrone

Share this post


Link to post
Share on other sites
4 hours ago, arpetrone said:

Another reason I want the option of cone 10 is because I have some brand new Sheffield 42 stoneware clay I haven’t even had a chance to put to use yet. It’s a c6-10 clay - would it still be vitrified/functional enough if only fired to c6?

 

Unlikely to be tight enough at ^6 for pots that hold liquids since the posted absorption at ^10 is 1.2 %  I wouldn't consider the cost of a box of clay when buying a kiln, use it for practice work, experimenting with, mold making, non-functional pieces etc. 

Share this post


Link to post
Share on other sites
On 4/6/2018 at 7:41 PM, arpetrone said:

Very interesting @Stephen, thanks for sharing. I hear you about the size of the Caldera, now that I think about it, it probably is too tiny. The 12x13 from Seattle Pottery Supply looks like a pretty sweet little and I would probably go for that no doubt if it fired to cone 10. Now I'm just as lost as I was in the beginning because I would like the option of firing to cone 10. 

Ya know not sure why they changed the specs. Mine fires to 10 although I never go past 6 either. Never seriously considered firing an electric to 10 for all the reasons Neil stated. cone 6 seems to be the sweet spot for oxidation and 10-12 for reduction. Personally I would give the clay on-hand a second thought when deciding on a kiln. Just toss or use for something else. You might be able to donate it to a center.

Neil, I am curious if the same rules apply on a small 1cf kiln and struggling to hit max 6. I would think the max on these is probably due to the 120V but hitting 6 seems easy and fast in my little one. Not sure about wear because as a glaze test kiln it gets used so seldom but clicks through the same program as its big brother with no issues when I do use it.  Since that little model 12 was rated cone 10 when I bought is a while back now I am willing to bet they changed that specs but likely not the kiln.      

Edited by Stephen

Share this post


Link to post
Share on other sites

The rules apply to kilns of any size. If you always fire to its max temp, you'll have to change out your elements more often. Think of it this way- everything has to be perfect for it to reach its max. As soon as the elements start to wear, they start struggling to reach the max. In a short while they can't get there at all. Now, think of firing 4 cones lower than the max. The elements can wear a lot more before the wear becomes an issue. So you don't have to replace them as soon.

Share this post


Link to post
Share on other sites

I of course defer to your knowledge on the subject and it makes sense to go larger than you need to be able to have them wear longer before replacing. My little one is in storage until the end of the month but will certainly check the plate when I get it here.

I guess you just have to do the math and make a decision. I know I figure about 150 or so firings for a set of elements and for the little ones I think a set runs around a hundred so that's about 60 cents a firing for element replacement and if its cut by half firing a cone 6 to cone 6 then that bumps to a buck twenty. I always fire to 5 with a 20 minute hold. So there is that.

Hope mines a 10 like I think it is B)

Edited by Stephen

Share this post


Link to post
Share on other sites

I make small things like jewelry, tile, small handbuilt items so my Olympic 120v Doll Kiln is about the perfect size. It would take me a long time to fill a larger kiln and I might only see finished pieces a few times per year that way.  I like to try new surface treatments a lot so I need feedback into whether it works or not more often than every 6 months. I've fired it 220 times over the past 5 years or so, bisque and Cone 5, everything still functions, elements look good but the thermocouple is getting a bit crispy. I don't see any reason to fire to Cone 10. I also fire metal clay, specifically copper and bronze which are fired in a steel vessel full of coconut fiber charcoal. I'm by no means 'easy' on this kiln. Using local power rates, I calculated that a Cone 5 firing costs about $1.50 for energy, and I add in another $1 per firing for kiln part replacement costs. I use the 'vary fire' method on the Bartlett controller so I can add in cooling segments as the kiln does crash quite rapidly (-600F in 30 minutes). I don't really see a huge difference with the cooling program though because I'm using commercial glazes. These glazes were designed to look good over a wide range of firing variables, kind of hard to mess up ;)

All in all I've been very happy with the small kiln, for the work that I make. I hope to go into tile production some day, at which point I'll buy a larger, gas-fired kiln.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×

Important Information

By using this site, you agree to our Terms of Use.