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Electric Raku Fire


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#1 Cass

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Posted 25 September 2012 - 12:15 PM

our 17" x24" Cress has been a workhorse for us for 12+ years




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all in all i would guess it has handled 300 loads, always even heating...very reliable results. I would say that the predictability of this kiln has been a major factor in our having been able to make a business and career of Raku.


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full kiln height 24" piece ^^^


full kiln diameter 16" piece vvv



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#2 Marcia Selsor

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Posted 26 September 2012 - 02:20 PM

Cass,
I always heard that raku was tough on elements. Glad to see you are proving differently. Have you had the same elements for 12 years?
curious to know if it is hard on elements or not.
Nice raku pieces.
marcia

#3 Cass

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Posted 26 September 2012 - 04:18 PM

i had heard that too, and was forewarned...but, alas yes, these are still the original elements. i have a backup set that have been sitting in the package for 8 years!

it may be too that this kiln size is ideal for minimal wear on the elements, and the kiln lid as well (still original too), a larger kiln might have drooping and broken elements by now

way i figure it, even if i were replacing all the elements every year it would still be a negligible cost of doing business

i think this is really the ideal setup for a classroom situation too: safe, reliable results.....used it for many beginner students and there was never a problem






#4 Benzine

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Posted 26 September 2012 - 10:06 PM

i had heard that too, and was forewarned...but, alas yes, these are still the original elements. i have a backup set that have been sitting in the package for 8 years!

it may be too that this kiln size is ideal for minimal wear on the elements, and the kiln lid as well (still original too), a larger kiln might have drooping and broken elements by now

way i figure it, even if i were replacing all the elements every year it would still be a negligible cost of doing business

i think this is really the ideal setup for a classroom situation too: safe, reliable results.....used it for many beginner students and there was never a problem







That's amazing, that you are still using the original elements. I had a classroom kiln, which required the elements to be replaced twice in five years, and I was only firing to cone 04 max!

It would be nice if I could use my current classroom kiln for raku, but it is not in a place that would work well for the process.

I like the pics you posted by the way. Seeing the glowing wares never gets old.
"Anything worth believing, is worth questioning"

#5 Cass

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Posted 26 September 2012 - 10:55 PM

hi benzine...are the bricks in bad shape in that kiln, elements falling out of their grooves? we use a skutt 27" for bisque to 03 and it also hasn't needed elements in i don't know how long, years

thanks for the pic comment...that was taken by a newspaper photographer, thats why no face shield and why i have the thing a foot from my face, lol , glory shot

#6 nancylee

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Posted 27 September 2012 - 05:17 AM

Hi Cass,
I am fascinated by this! I love raku'd, but don't want to mess around with propane. How fast do you fire up to temp? And what temp is It? I assume the.kiln is outdoors? I love te pics, by the way. Very brave, no mask!!!
Nancy
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#7 nancylee

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Posted 27 September 2012 - 05:18 AM

Hi Cass,
I am fascinated by this! I love raku'd, but don't want to mess around with propane. How fast do you fire up to temp? And what temp is It? I assume the.kiln is outdoors? I love te pics, by the way. Very brave, no mask!!!
Nancy


Scratch that one observation, I see kiln is inside.
Nancy
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#8 Cass

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Posted 27 September 2012 - 07:13 AM

yes the kiln is in a small shed...to the left you see the edge of two swinging doors to the outside...so i pivot with the work to a concrete pad just at the threshold, do my 'work' on them, then pivot again to the waiting trashcans that are fully outdoors. May seem complicated, but it feels luxurious compared to some of the absurd setups from our past, such as carrying the work 20+ feet to the can area!

first fire from a cold kiln is 2-2.5 hours...subsequent fires can be as little as one hour, depending how hot we have kept the kiln during transition...we have fired as many as 12 fires in a day (oooof), but 5-6 fires makes for a good work day

temp is approx 05, though all glazes are judged by eye, no pyrometer or cones ever, you need to see the surface directly




#9 nancylee

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Posted 27 September 2012 - 09:06 AM

yes the kiln is in a small shed...to the left you see the edge of two swinging doors to the outside...so i pivot with the work to a concrete pad just at the threshold, do my 'work' on them, then pivot again to the waiting trashcans that are fully outdoors. May seem complicated, but it feels luxurious compared to some of the absurd setups from our past, such as carrying the work 20+ feet to the can area!

first fire from a cold kiln is 2-2.5 hours...subsequent fires can be as little as one hour, depending how hot we have kept the kiln during transition...we have fired as many as 12 fires in a day (oooof), but 5-6 fires makes for a good work day

temp is approx 05, though all glazes are judged by eye, no pyrometer or cones ever, you need to see the surface directly




Hmmm...interesting, I have an old Skutt kiln, I got a new kiln because the Skutt would bisque to 05, but not get to Cone 5 or 6. Maybe I can use that for raku? I haven't done the crackle yet, I love the Copper sand, I use that one the most. My instructor looks through the kiln hole on top and says that the glaze is still ugly at some point, but I don't know what it looks like when it is ready? Could you describe it? You have been very generous with your knowledge already. Thank you,
nancy
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#10 neilestrick

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Posted 27 September 2012 - 09:26 AM

Nice work.

On a safety note, it looks to me like the cinder blocks under the kiln are set so the openings are vertical. Am I correct, or am I just not seeing it right in the photo? If so, this means the heat from the kiln can radiate right down to the wood floor. At some point that will become so dry that it will start to burn. Turn the cinder blocks so the openings are horizontal so that air can flow through the blocks.

Ever thought of converting to propane? You could get out 2 to 3 times as much work.
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#11 Cass

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Posted 27 September 2012 - 09:56 AM

each type of glaze will look a bit different when mature...for the most part they will look glassy, you will see the reflection of the elements in the glaze...a copper matt is probably the hardest to judge...kiln color is bordering between orange and yellow...trial and error, and experience are your best guides

the bricks...now i'm curious, i will take a look...they have been like that 6 years with no problems, so...hmmm

as for propane...have thought about it, then thought...no. around here the startup and conversion of getting that all going would be high, and i'm admittedly set in my ways. the pace of firing, and my output are very well synched with my speed of making, etc

#12 Marcia Selsor

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Posted 28 September 2012 - 12:49 AM

Did you mention how long it takes to reach temperature? I looked but missed it if it is in this thread.
I do a lot of raku and have my kiln to be an adjustable size by adding more bricks to the wall height.
just curious to know how long you take to reach temperatures and do you reload and fire again...how long that takes.
It is an interesting alternative to propane and one that many can readily access.
Marcia

#13 kilnpriestess

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Posted 28 September 2012 - 02:23 AM

i had heard that too, and was forewarned...but, alas yes, these are still the original elements. i have a backup set that have been sitting in the package for 8 years!

it may be too that this kiln size is ideal for minimal wear on the elements, and the kiln lid as well (still original too), a larger kiln might have drooping and broken elements by now

way i figure it, even if i were replacing all the elements every year it would still be a negligible cost of doing business

i think this is really the ideal setup for a classroom situation too: safe, reliable results.....used it for many beginner students and there was never a problem

Aother factor that seems to have a lot to do with how long the elements last in an electric fired raku kiln might have to do with how much your raku glazes spit when they start to boil and bubble. If the pieces are kept at a safe distance from the kiln walls when the kiln is firing this might be another reason for why the elements have lasted so long. I know that glazes with gerstly borate are master spitters.





#14 Denice

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Posted 28 September 2012 - 08:13 AM

Interesting discussion on firing raku in electric, that was the first firing I did in high school. Believe it or not we did it inside of the classroom, our teacher didn't put the pieces in any newspapers just directly in to the big clay sink and had us run water on them when they had cooled a bit. Denice

#15 Cass

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Posted 28 September 2012 - 10:42 AM

Did you mention how long it takes to reach temperature? I looked but missed it if it is in this thread.
I do a lot of raku and have my kiln to be an adjustable size by adding more bricks to the wall height.
just curious to know how long you take to reach temperatures and do you reload and fire again...how long that takes.
It is an interesting alternative to propane and one that many can readily access.
Marcia


yes, first fire is 2-2.5 hours to approx ^05...subsequent fires in as little as one hour...i tend to err on the side of caution....as many as 10 fires a day

as for the bricks: i moved the kiln aside, and lol, only then did i remember i had half filled the spaces with sand years ago when setting up....boards are protected and my kiln bottom still has no cracks...i say..'if it ain't broke.....', good lookin out though nielestrick

none of the glazes i use are bubblers, htey just flatten and go glassy, so i had never thought of that possible factor in element longevity, good point Denice!

#16 neilestrick

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Posted 28 September 2012 - 11:40 AM

the bricks...now i'm curious, i will take a look...they have been like that 6 years with no problems, so...hmmm



That's how it goes. No problems for several years, but the whole time the wood beneath the kiln is drying out and the flashpoint is getting lower, then one day it starts to burn...

Here's a note from a web site for a company that does chimney restoration in historic homes:
"Ninety percent of historic homes have wood in direct contact with the chimney. When wood is new, it has a flash point of 414 degrees F. Subjecting it to heat dries the moisture out of the wood, lowering the flash point to as little as 200 degrees F."
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#17 Cass

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Posted 28 September 2012 - 12:01 PM

see one post up neil...all good, safe

not a bad idea though, probably will change it just for extra safety...

it's a raku fire day!...yay, already pulled 2 loads

#18 Mark C.

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Posted 28 September 2012 - 12:46 PM

I like to see working potters thinking outside the norm.This thread is all about that. The word on the street is electrics should not be used for raku and its a slam dunk this one has and done so for a long time-Great to read about. Thanks for sharing.

Menocino move to Montana that must be a story?
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#19 Cass

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Posted 28 September 2012 - 01:34 PM

thanks mark...been enjoying your insights on other topic as well

mendo to MT by a very circuitous route, there was a 3 year stint in france in between...we had decided to return to the US and almost went back to mendo, but at that moment the mountains were calling us...and, the poison oak was the clincher, i had it continuously the 18 mos we were down there, i'm super-allergic! ugggh....we do miss the coast though, we try to get somewhere on the coast at least once a year, usually oregon or washinton now....

#20 Benzine

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Posted 28 September 2012 - 07:49 PM

hi benzine...are the bricks in bad shape in that kiln, elements falling out of their grooves? we use a skutt 27" for bisque to 03 and it also hasn't needed elements in i don't know how long, years

thanks for the pic comment...that was taken by a newspaper photographer, thats why no face shield and why i have the thing a foot from my face, lol , glory shot


I'm at a different school, so it's a different kiln now. But no, the kiln bricks were in good shape, no element sagging. So, I honestly have little idea why the wore so quickly. The only other thing I can think of, is that the bisque fire program, I had set, was too drawn out, and prematurely aged the elements.

I didn't question the lack of face shield in the picture, as I just go with eye protection myself. But I did wonder why you had it so close to your face. That was probably a bit "warm".
"Anything worth believing, is worth questioning"




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