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basics cones firing time

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#1 xxiixx

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Posted 01 July 2016 - 10:48 AM

Hi wonderful crafters!

 

I've recently acquired a kiln and am ready to jump into ceramics!

 

Though I've done loads of research, I'm still a bit confused about firing times and this whole cones system!

 

I'm using Stoneware Crank clay, and pretty sure I need to fire on a 6 cone. Silly question, does this just mean the temperature? (2269f?) or does it also mean I need to buy one of those actual cones? (Attached image)

 

 

I'm quite confused by all this information, especially because I've read conflicting things.

 

Thank you for your help!

 

x

 

 



#2 oldlady

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Posted 01 July 2016 - 03:01 PM

go to your local library and pick up several books on clay basics.  these will be the thicker ones that have a glossary in the back.  they might be old, but the info is still the same.  you need to know the alphabet before you write your novel.  same with clay work.  i am not discouraging you, only encouraging you to get some basic information so you will not be confused.  cones are used to measure heat work.  temperature is only a tiny part.


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#3 Marcia Selsor

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Posted 01 July 2016 - 03:08 PM

there are always more than one answer to something in ceramics. Ask three potters a question and you get five answers. 

Yes, go to the library, start reading and also go look at its if you are near any shops, art centers or galleries, craft shows, etc. Maybe you can handle some pieces and feel how they balance or feel. Talk to people. Ask questions. If there are any classes in your area, take one just to get acquainted to the clay.

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#4 High Bridge Pottery

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Posted 01 July 2016 - 03:14 PM

This explains it pretty well, firing ceramics is about transferring heat into the pots so takes time. Take note of the heating rate oc/h last 100 of firing.

 

wall_chart_horiz.gif


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#5 Pugaboo

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Posted 01 July 2016 - 03:37 PM

A baby potter. Oh boy! Lol sorry we have all been where you are and it gets less confusing as you learn the language and tools involved. I would suggest the library books as well, it will fill in your vocabulary and also help you direct your creative journey by figuring out what type stuff intrigues you.

More direct... If you don't have the manual for your kiln and controller go to the maufacturers website and download them. Read them, Google the words you don't know then read them again. You will be amazed at how fast you pick up the lingo. Depending on your controller it might have preprogrammed settings to help get you started. What type kiln and controller do you have?

Cone 6 is 2232-2269, approximately, this is where the heat work comes in to play. If you fire your kiln to 2232, which is a cone 6 (for me anyway, again it varies a few degrees depending on the kiln load and ramp rate) and your controller registers the top temp as 2232 BUT when you open the kiln the Orton Cone 6 you have on your kiln shelf isn't bent all the way it means you didn't get enough HEATWORK to reach cone 6. Or if you open it and the cone is a little collapsed blob you have gotten too much HEATWORK. Does that kind of explain it a bit?

Cones are made to react to the heat work inside the kiln and will begin to melt causing them to bend if you reach the correct temperature in a certain amount of time (this involves the ramp rate during the final firing segment which is so many degrees over so many minutes). Look up Orton Cones and read up on how they work and that will tell you a lot. It's not as scary as it seems a lot of potters use their digital controller to control the firing schedule and use the cones to verify that the work was actually fired to the correct temperature. I usually only put 1 Orton cone on the center shelf of my kiln for each firing UNLESS I am trying to test something then I will put 3 cones in each shelf in the kiln: a cone 5, 6 and 7. This will tell me that on THIS shelf the temperature and heat work reached a particular temperature by how much the cones have bent. You use a 5 to tell you tell you if it's getting close but not quite to the temperature you want, cone 6 is the cone you are looking to bend perfectly and the cone 7 will tell you if it got too hot and over fired.

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#6 bciskepottery

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Posted 01 July 2016 - 07:11 PM

Check around for another potter or a community studio and ask if you can watch/help load and fire a kiln with one of their staff.  Reading is great, watching videos is great . . . but actually helping someone is the best way to learn all the little nuances they omit from the books and videos.  And, you get to learn from others' mistakes.  Every kiln you load/unload is the equivalent of a Ph.D. in firing. 



#7 LeeU

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Posted 01 July 2016 - 07:44 PM

Got my own question...on the Orton chart, what means the numbers in the Cones row (for Self Supporting F)?    27-108-270  Thanks.


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#8 Min

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Posted 01 July 2016 - 07:53 PM

Got my own question...on the Orton chart, what means the numbers in the Cones row (for Self Supporting F)?    27-108-270  Thanks.

 

The heating rate per hour for the last 200 degrees (fahrenheit). So for ^6 if you go at 108F per hour for the last 2 hours the final temp would be 2232F. (but check with cones to verify)



#9 bciskepottery

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Posted 01 July 2016 - 07:54 PM

Got my own question...on the Orton chart, what means the numbers in the Cones row (for Self Supporting F)?    27-108-270  Thanks.

Those are rates of temperature climb the last hour . . . 27 degrees/hour, 108 degree/hour, 270 degrees/hour.  How fast temperature climbs affects how much heatwork occurs.



#10 GiselleNo5

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Posted 01 July 2016 - 09:24 PM

I found a simple pyrometric cone chart that I keep right by my computer for reference. After four and a half years of pottery, I now can tell you that Cone 05 is about 1900F and Cone 5 is about 2200F right off the top of my head but I still have to check for all the other ones. Then the fact that they count down from 022 to 01, then start counting back up from 1 to 13 .... I know there is a reason it's done that way but it's SO. Confusing. To beginners. 

 

Just a side note ... recently I was watching a Periscope by a potter in England. 

 

There they just say what temp they fire too without all this cones nonsense. SO MUCH BETTER. 

 

Here is the chart I printed out: https://s-media-cach...8101a3f2ac4.jpg


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#11 glazenerd

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Posted 01 July 2016 - 10:40 PM

20/18:

How about looking at firing a kiln in more familiar terms: cooking.The principles are not that much different: just different parameters. Lets start with a meat thermometer: you use one to cook a piece a meat to a specific temperature. You stick the thermometer in the meat until it reads the desired temperature. Cones likewise measure a specific temperature, the only difference is you lay beside what your cooking: not in it. Which brings us to a kiln term: heat work. A thermometer measure the temperature inside the meat, not the air around it. A cone measure the heat that has been absorbed, not the air around it. Another way to view it: a fish fillet is broiled quickly at high heat, and yet it cooks through because it is thin. You subject a steak to that same cooking cycle and the outside will be seared, but the inside slightly cooked. Subject a roast to that same cooking cycle and the outside will be seared, but the inside will be blood raw- perhaps still cool. You control the oven to control the type of meat you are cooking- a kiln is no different. You lower the temperature of the oven so the heat reaches the center of the roast.

All the firing cycles you see in the Orton chart shows the results of a firing using low. medium, or high heat. (Degrees per hour). You start the firing lower to equalize the heat in all the pieces in the kiln. Once you have done that you can heat them faster, up until the end of the firing. Once you near the end of the firing, it is slowed back down to again equalize the heat in the entire kiln. The hardest thing to grasp is; its not the air temperature that determines if the clay and glaze is done cooking: it is the amount of heat that is transferred/absorbed by each piece.

So now we go back to the oven scenario: if you throw a couple of steaks in the oven you know they will absorb heat uniformly and you can cook them faster and use a higher heat. Now imagine you stuff your oven with 50 or 100 steaks? You have to lower the temperature and extend the cooking time to make sure they all cook evenly. So if you are firing a small kiln with just a few pieces: you can go faster. If you are firing a large kiln with many pieces, then you have to slow down. Clay and glaze are just like different cuts of meat: they require different cooking temperatures and times.

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#12 Chilly

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Posted 02 July 2016 - 01:09 PM

Just a side note ... recently I was watching a Periscope by a potter in England. 

 

There they just say what temp they fire too without all this cones nonsense. SO MUCH BETTER. 

 

 

Many in the UK use cones, just coz you watched one potter who didn't, doesn't mean we all don't.


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#13 GiselleNo5

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Posted 02 July 2016 - 03:53 PM

 

Just a side note ... recently I was watching a Periscope by a potter in England. 

 

There they just say what temp they fire too without all this cones nonsense. SO MUCH BETTER. 

 

 

Many in the UK use cones, just coz you watched one potter who didn't, doesn't mean we all don't.

 

 

Ahh sorry I generalized!! :( 


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#14 LeeU

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Posted 02 July 2016 - 04:22 PM

Of course, on the Orton chart, right in front of my very eyes, it says, in plain English, and I quote: "Heating rate *F/hour (last 200 *F of firing"   :P  :lol:  :rolleyes:   She looks, but, alas, she does not see. 


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#15 Stephen

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Posted 04 July 2016 - 12:30 PM

I assume the 'cone nonsense' was misinterpreted Giselle, even is you're willing to risk failure, the equipment is going to wear out at the very least.

 

That's not the same as failing really since failing is more spontaneous and will happen any time BUT every kiln here is going to wear out and unless you are just preemptively changing elements and related hardware then you will miss the opportunity to do it at the right time and not screw up any pots.   

 

We do this for a living and we are extremely picky about the finish work and overall quality so waiting for a crappy glaze load or two instead of using cones is certainly not something I would even remotely think about doing as a lost glaze load or two could mean that weeks paycheck. We also do a lot of prototyping and that means we really need to know that from concept to production all new designs were all consistently fired to the exact same temp every time.



#16 GiselleNo5

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Posted 04 July 2016 - 04:20 PM

I think I was not clear in my meaning.

Using cones to make sure one's kiln is firing properly is vital.

I meant using the term cones in speech instead of just saying what firing temperature we're using.

I was just referring to how we talk about our firing temperature. All potters I've talked to here say what cone they're firing to. This potter said what temp which I thought was simpler.

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#17 Chilly

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Posted 04 July 2016 - 05:18 PM

I was just referring to how we talk about our firing temperature. All potters I've talked to here say what cone they're firing to. This potter said what temp which I thought was simpler.

 

I much prefer to think in cones.  For each cone there is a range of temps, and at different rates of firing.  Much easier to know that bisque is ^04, low-fire glaze is ^06, stoneware is ^6 or ^8.......


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#18 JohnnyK

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Posted 10 July 2016 - 09:23 AM

Then there is the Ice Cream Cone....temp:26-32F...



#19 Chilly

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Posted 11 July 2016 - 08:56 AM

Then there is the Ice Cream Cone....temp:26-32F...

 

I did a "factory tour" of Wall's ice cream in Gloucester a few years back.  Was amazed to find they pumped "frozen" ice cream from the mixing floor to the making floor at below -5C.  No cones involved, this was for magnums and viennettas.


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