Daraburn@AOL.COM on fri 9 jul 04
I have a Skutt KM 1027 kiln and fire to cone 6. I have fired I think approx
200 firings (almost half of which would have been bisque). I got an error
message which indicated that my kiln could not keep up the heating schedule as it
neared top temp which may indicate worn our elements. What?!!! The manual
says it should fire thousands of times. i notie one little section of the
lower element that is dark and the rest "look" OK. I called Skutt and the tech
said that my firing schedule (slow cool as per Ron and John) for semi-mattes
would cut the life of the elements in half!!! Anybody know anything about this?
Does anyone have a firing schedule for semi-mattes that is not too slow but
still gives good semi-mattes? Advice please.
Dawn in Tennessee
Cynthia Bracker on fri 9 jul 04
Unless you spent the extra money and bought the APM elements, I'd say
200 firings is pretty good if about half of them are to Cone 6. I'm
not sure where in the Skutt manual it says the elements would be good
for thousands of firings. The kiln itself may last thousands of
firings, but not without changing out the elements several times. Skutt
elements are not too expensive ($41.00 each retail price X 6 in the kiln
= $246.00 and most suppliers will give a small discount on elements).
They are pretty easy to change yourself, or you might be able to find a
kiln tech in your area. DON'T hire an electrician to do it. You'll pay
too much! Try calling Tammy at MidSouth Ceramic Supply in Nashville,
(615) 242-0300.
Cindy Bracker
Bracker's Good Earth Clays, Inc
Daraburn@AOL.COM wrote:
>I have a Skutt KM 1027 kiln and fire to cone 6. I have fired I think approx
>200 firings (almost half of which would have been bisque). I got an error
>message which indicated that my kiln could not keep up the heating schedule as it
>neared top temp which may indicate worn our elements. What?!!! The manual
>says it should fire thousands of times. i notie one little section of the
>lower element that is dark and the rest "look" OK. I called Skutt and the tech
>said that my firing schedule (slow cool as per Ron and John) for semi-mattes
>would cut the life of the elements in half!!! Anybody know anything about this?
>Does anyone have a firing schedule for semi-mattes that is not too slow but
>still gives good semi-mattes? Advice please.
>
>Dawn in Tennessee
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
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>
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>
Charles Moore on fri 9 jul 04
Hi, Dawn, the technician that I talked with at Skutt told me the same thing:
slow cooling would shorten the life of the elements. I am not sure of the
truth of this piece of information; I simply tucked it away in my head.
I have fired, both bisque and ^6, for quite a while without an element
failure, so I am not sure about the accuracy of the Skutt technician's
advice.
I am going to send this message on to John Helsselberth to get his response.
Charles Moore
Sacramento
----- Original Message -----
From:
To:
Sent: Friday, July 09, 2004 8:59 AM
Subject: Elec kiln elements wearing out too soon?
> I have a Skutt KM 1027 kiln and fire to cone 6. I have fired I think
approx
> 200 firings (almost half of which would have been bisque). I got an error
> message which indicated that my kiln could not keep up the heating
schedule as it
> neared top temp which may indicate worn our elements. What?!!! The
manual
> says it should fire thousands of times. i notie one little section of the
> lower element that is dark and the rest "look" OK. I called Skutt and the
tech
> said that my firing schedule (slow cool as per Ron and John) for
semi-mattes
> would cut the life of the elements in half!!! Anybody know anything about
this?
> Does anyone have a firing schedule for semi-mattes that is not too slow
but
> still gives good semi-mattes? Advice please.
>
> Dawn in Tennessee
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Cindi Anderson on fri 9 jul 04
L&L told me basically that same thing. They said the only time they really
recommend APM elements is for firing crystalline glazes because the slow
cooling does affect the molecular structure of the elements and reduces
their life. So I think it is true. But probably not enough to be worried
about. A set of elements isn't that expensive and whether you get 200 or
300 firings doesn't seem to make that much difference. Those of you who
fire a lot of crystalline glazes, I would be interested to know how long
your elements last.
Cindi
----- Original Message -----
> Hi, Dawn, the technician that I talked with at Skutt told me the same
thing:
> slow cooling would shorten the life of the elements. I am not sure of the
> truth of this piece of information; I simply tucked it away in my head.
>
> I have fired, both bisque and ^6, for quite a while without an element
> failure, so I am not sure about the accuracy of the Skutt technician's
> advice.
John Hesselberth on fri 9 jul 04
Hi Dawn,
As soon as I read your message I sent an email to Mike Sievers (and
have copied him on this message), the marketing manager at Skutt,
asking if this 50% reduction in element life with our firing schedule
were his position. The fact that Skutt's tech rep was making similar
statements came to Ron's and my attention last February and we had an
initial face-to-face discussion with Mike at NCECA in March. Since then
we have exchanged several emails on the subject. Since it is now after
5 p.m. in Oregon I doubt I will hear back from Mike until next week and
decided I am not willing to let the question you raised lie there over
the weekend. So here is what Ron and I know.
According to Mike our firing schedule should not be a problem with kiln
element life; however he is concerned that some people may be
misreading or misinterpreting our firing schedule. He says that holds
longer than 20 minutes above 2000 deg F will result in reduced element
life (in our book we recommend a hold of 20 minutes at peak
temperature; on our website, in a revised schedule, we recommend a hold
of 15 minutes at peak temperature)--though he has never mentioned a 50%
number or tried to quantify that reduced life in any communication with
me.
In addition, at NCECA, I made it a point to discuss this issue with 3
other kiln manufacturers. None said our firing schedule should be a
significant problem with respect to element life. The most negative
comment I could elicit was that there might be a small, barely
measurable reduction in life. The consensus, I concluded, from those
discussions was "you'll never see it".
Also, I would agree with Cindy Bracker that 200 firings, if half or
more are to cone 6 (the other half being bisque) is pretty good life
for a set of elements. I certainly don't do any better than that even
before I started slow cooling. You might want to reread Skutt's manual
very carefully and see if 'thousands' is what they are really
suggesting for element life to cone 6.
Hopefully, Mike Sievers, will respond to your post directly to Clayart;
however if he responds to me and gives me permission I will forward his
response to the list when I receive it.
As a last point, and addressing the last line of your post, the revised
schedule I have posted on our web site would move in the right
direction of minimizing any potential reduction of element life. It
increases the rate of drop from peak temperature (after the 15 minute
soak) down to 1900 deg F from 150/hour to 500/hr. Nothing much in the
way of crystallization happens in this zone anyway, so you may as well
let the kiln drop through it quickly. It will save you time, energy,
and, possibly, element life. Specifically that schedule is:
Rate To Temperature Hold
100 220 0
350 2000 0
150 2185* 15
-500 1900 0
-125 1400 0
* This temperature must be adjusted to match cone 6 with your
particular thermocouple and controller.
And, yes, the above schedule is a tiny bit different from the one I
showed at NCECA -- I am always fiddling a bit -- but not significantly
so. The schedule I showed at NCECA can be seen at:
http://www.frogpondpottery.com/nceca2004/p21.html
I hope all this helps.
Regards,
John
On Friday, July 9, 2004, at 11:59 AM, Daraburn@AOL.COM wrote:
> I have a Skutt KM 1027 kiln and fire to cone 6. I have fired I think
> approx
> 200 firings (almost half of which would have been bisque). I got an
> error
> message which indicated that my kiln could not keep up the heating
> schedule as it
> neared top temp which may indicate worn our elements. What?!!! The
> manual
> says it should fire thousands of times. i notie one little section of
> the
> lower element that is dark and the rest "look" OK. I called Skutt and
> the tech
> said that my firing schedule (slow cool as per Ron and John) for
> semi-mattes
> would cut the life of the elements in half!!! Anybody know anything
> about this?
> Does anyone have a firing schedule for semi-mattes that is not too
> slow but
> still gives good semi-mattes? Advice please.
>
> Dawn in Tennessee
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.com
Snail Scott on sat 10 jul 04
At 11:59 AM 7/9/04 EDT, you wrote:
>...I called Skutt and the tech
>said that my firing schedule (slow cool as per Ron and John) for semi-mattes
>would cut the life of the elements in half!
Stands to reason that a firing that takes twice
as long might use up twice as much element life.
Also, they sell most of these kilns to people
doing low-fire work (schools and 'paint-your-
bisque' outfits, etc), and seem to write the
boilerplate instructions with them in mind. A
stated estimate of 'thousands of loads' (did it
really says 'thousands'?) might perhaps be
plausible if you fire only to a max of ^04 and
mostly lower, but ^6 takes a LOT more element
life. (Even worse at ^10.)
I'd say 200 firings is a pretty tolerable run for
a set of elements firing to mid-stoneware temps
on a slow cycle.
If you want slow-cooled stoneware glazes, you're
never going to have the element life of someone
who fires to ^06 and shuts it off. It's a choice
you have to make. You can ease the strain on the
elements by adding insulation to the outside of
the kiln and extending the jacket to fit, though
this probably means having to extend the control-
box attachments, too, depending on the style
you've got. This will give a slower cool with
less 'firing down' needed, but honestly, it's not
the firing down that's the big strain on elements;
it's the full-power effort needed to reach the
higher temperatures in the first place, (though
extra insulation will help a little with that,
too). I've also heard good reports about the ITC
coatings extending element life, but in the end,
higher temperatures and longer firings simply use
more element life.
Elements are going to need replacing eventually,
no matter what you do. The question is, are you
willing to replace them more often, in order to
do the work you have in mind?
-Snail Scott
Ron Roy on sun 11 jul 04
Hi Dawn,
Just to add to what has already been said - do you have a kiln vent
attached to your kiln?
Reduction happens in electric kilns at different stages and reduction will
shorten the life of elements dramatically. If fresh air is being constantly
drawn into a kiln (with a vent system) elements will last longer.
200 firings on a set of elements seems normal to me but there are other
factors as well.
If elements are not stretched properly you can get hot spots which will
cause premature failure.
Some kilns have connectors that allow the connections to and from the
elements to loosen over time and that could cause premature failure.
RR
>I have a Skutt KM 1027 kiln and fire to cone 6. I have fired I think approx
>200 firings (almost half of which would have been bisque). I got an error
>message which indicated that my kiln could not keep up the heating
>schedule as it
>neared top temp which may indicate worn our elements. What?!!! The manual
>says it should fire thousands of times. i notie one little section of the
>lower element that is dark and the rest "look" OK. I called Skutt and the tech
>said that my firing schedule (slow cool as per Ron and John) for semi-mattes
>would cut the life of the elements in half!!! Anybody know anything about
>this?
>Does anyone have a firing schedule for semi-mattes that is not too slow but
>still gives good semi-mattes? Advice please.
>
>Dawn in Tennessee
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Arnold Howard on mon 12 jul 04
What wears elements is firing to a temperature that the kiln can barely
reach. The easier the kiln can reach the maturity temperature, the longer
the elements will last.
I don't think a slow cooling will affect element life much.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
arnoldhoward@att.net / www.paragonweb.com
----- Original Message -----
From:
I called Skutt and the tech
> said that my firing schedule (slow cool as per Ron and John) for
semi-mattes
> would cut the life of the elements in half!!! Anybody know anything about
this?
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