Stephen Lewicki on fri 18 jan 02
This was written as a response the posting of Kim Lemonakis (topic: clayart =
digent -l&l kilns) I changed the topic to a new name to attract a wider =
audience for this message).
Dear Kim =96
It is a shame that you have not gotten the life out of your elements that you =
expected. I do sympathize with your budget problems. I have followed your =
various postings on Clayart with interest and concern. I appreciate the =
opportunity to address your concerns in detail not only for your benefit for =
the greater benefit of the community. I am of the opinion that an honest dialog =
between manufacturers and users is extremely helpful for all. Ignorance of the =
problems we all face is most unhelpful.=20
The shortening of element life is a complicated issue and has many causes. We =
have had the same element designs in our kilns for over 40 years. We have many =
customers who get fantastic life out of their elements even under high fire =
conditions, and, in fact, we get very few complaints about element life. We =
introduced heavy-duty elements in our Jupiter kilns a few years back. These use =
a heavier gauge wire, which helps reduce surface temperature and improves =
oxidation resistance over time as well as being mechanically stronger. In any =
case I mention this to discount the possibility that the design of the element =
is faulty.=20
At one point you said that you fired to cone 6 once a week for 7 months (4 X 7 =
=3D 28 firings). On another posting you specifically said that you only fired =
to cone 6 12 times. When I pulled your invoice I just found that the kilns were =
shipped in October of 2000 (which would have been 12 months). I mention this =
not as a complaint or challenge but rather to educate the community about the =
sort of issue we, in technical support, grapple with every day. People tell us =
all sorts of things (for all kinds of reasons such as the fact that they =
don=92t remember or don=92t know) and sometimes this makes it difficult to =
troubleshoot problems. It makes it even harder when we are being blamed for =
everything that can go wrong. That is one reason we have a generous pro-rated =
element replacement policy. It gets us out of the blame game and serves our =
customers fairly and respectfully without making us feel like we are being =
taken advantage of.
In any case, a few points about element life and the causes of element =
degradation. First, in all electric kilns of the type that L&L, Skutt, Paragon, =
Olympic etc make we all use pretty much the same element wire which is an alloy =
composed of iron-aluminum-chrome (Kanthal A1 or Hoskins 875). Some =
manufactures, including us, offer a very expensive alternative, a sintered =
version of this called Kanthal APM which has been reported to last much longer =
but at such great cost that it is not recommended because of the replacement =
cost if you accidentally contaminate an element with glaze). All the relatively =
inexpensive electric kilns are using this alloy at its absolute limit. When the =
kiln is near cone 10, the element surface temperature can be close to 100 =
degrees F hotter. The alloy will also start to melt at a temperature not very =
far above this. Actually our thin hard ceramic element holders help with this =
condition because they have less insulating wall between the element and the =
kiln interior. It is simply the nature of the technology available at a =
reasonable and affordable cost and it is not without problems and issues that =
cannot be readily solved. We do our best to design elements that maximize life =
under the harsh conditions of pottery kiln use. Stretch ratio, wire diameter, =
watt density are all balanced to maximize element life.=20
Contamination in the kiln (from clay) can also cause problems. The element =
alloy DEPENDS on a tight coating of aluminum oxide that forms on the surface. =
Sulfur, carbon and other contaminants in clay can wreak havoc with this oxide =
coating. This is one reason why kiln venting is so important. By the way I =
noticed that you did not get vents for your kilns (at least from us). Perhaps =
this is the real underlying problem with your kiln elements.
Another thing that can shorten element life is overloading the kiln or putting =
work too close to the elements. This can reradiate the heat of the elements =
back into the elements raising their surface temperature and dramatically =
decreasing element life.
The point was made in one of the responses to you that 2-1/2=94 brick =
inherently causes problems with element life at high fire. You will notice in =
our catalog that we recommend 3=94 brick and heavy-duty elements when planning =
on firing above Cone 1 (for instance Cone 6). It seems that one of the problems =
is, perhaps for budget reasons that you had no control over, the kilns you =
bought were not entirely appropriate for your intended use. It is important to =
understand the distinction between the fact that our 2-1/2=94 brick kilns CAN =
go to Cone 10 and the idea that you would want such a kiln for consistent =
high-fire operation.
There is an issue with using an automatic control in terms of heat up times. =
First of all the automatic control (if used in the Easy-Fire mode) can give you =
an error message that stops the firing. (This can actually save you from bad =
firings =96 which is why it is there). Second, when used with the three-zone =
feature the kiln is necessarily slowed down because, to get good uniformity, =
you must turn off sections for some of the time. It is a tradeoff. There are =
sophisticated features in the DynaTrol that can mitigate this. For instance you =
can set your LAG time higher which will do less of the uniformity correction. =
There is a feature called AUTOLAG, which suppresses the LAG feature until the =
end of the firing when it is more critical. Also, how you load your kiln =
matters. Top loading kilns want to fire colder on the bottom. People typically =
put more of their heavier work in the bottom. This exasperates the problem and =
makes the 3-zone system work against physics. Without a downdraft vent problem =
(which can do some of the uniformity correction) this is even more of a =
problem.
There is another problem with automatic controls and element life. Automatic =
kilns are turning elements on and off more often than manual kilns. The =
continual expansion and contraction of the elements may contribute to shorter =
element life. Also, soaks which are easier with automatic controls, do take =
some toll on elements. An important point to make, however, is that none of =
this is easy to quantify or know with any certainty. I have thought of setting =
up controlled tests but even if we went to the elaborate expense of designing =
and performing such tests (assuming one could even test for all the possible =
variables) it is the combination of so many factors that determines ultimate =
element life in real practice.
You also have working against you the fact that you are using 208 volts. This =
is nothing you have any control over but, in that particular kiln (the JD230) =
it does mean that the kiln has fewer watts (power) than you would have if the =
kiln were 240 volts. Therefore, as elements age it has more of an effect on =
performance. In fact this is a problem not only with L&L kilns for most other =
23=94 diameter by 27=94 high kilns that are operating on 208 volts and using a =
50-amp plug. For historical reasons and convenience people have wanted to have =
their kilns operate on a 50-amp plug. (I personally don=92t understand why =
having a kiln direct wired to a fused disconnect switch isn=92t just the =
standard way of doing things). In addition to that, on the manual kilns, the =
switches were all rated at 15 amps. On a 3-section kiln this meant that the =
amperage was limited to 45 amps. This is OK on a 23=94 by 27=94 high kiln at =
240 volts. However, when you move to 208 volts and maintain the amperage of =
less than 45 amps you are pushing limits. Then, if your voltage happens to be =
low (which can happen while you are firing so that you don=92t even know it), =
or if you overload the kiln, or if your elements age you WILL have a hard time =
getting to high fire temperatures. We actually do have a solution for this =
problem that few people have taken us up on although we are starting to promote =
it actively now. On our automatic kilns all our internal circuits are rated for =
20 amps (not 15 amps as they are on the manual kilns). So we designed a higher =
wattage element for the JD230 that takes advantage of this changed limitation. =
We do not charge anything more for this =96 the only difference is that the =
kiln needs a 70 amp circuit with a 60 amp circuit breaker. If that is something =
you can do without extra cost I would be more than happy to supply you with a =
set of these elements at a deep discount when the new elements you have give =
out =96 no time limit on this for you). I think it would helpful for other =
Clayart people to read and know about this option.
By the way one thing you can do to aid a situation where a kiln is underpowered =
is to put 2" of very inexpensive non-compressible calcium silicate under the =
kiln (and on top of the stand). YOu can get this at any decent industrial =
insulation supply house. This will help by adding more insulation and by =
reducing the natural coldness of the bottom section.
Let me ask you a rhetorical question. What would better customer service =
reasonably have been? We have always, I think, been easily available and, I =
think, helpful (although I admit not as thorough and exhaustive as I have made =
this missive). This past October we sold you 12 new heavy- duty elements at an =
80% discount ($100 total) going beyond even what our stated Pro-Rated element =
warranty would have been. We really do try hard to please everyone, and while =
we know this is not always possible, it is painful and difficult when any =
customer feels disappointed for whatever reason. I do hope my comments have =
been helpful to you and the rest of the Clayart readership. I would of course =
always welcome a personal call from you any time.
Stephen J Lewicki
President
L&L Kiln Mfg., Inc.
steve@hotkilns.com
Kim Lemonakis on sat 19 jan 02
Steve,
It amazes me that you have chosen to address all these technical issues in
this public forum. When I spoke to you on the phone you made no attempt to
express any of the issues that I am reading today. You referred me to a man
that you said was more knowledge of the computer components of the kiln and
that seemed to be my problem. He was a nice enough fellow and did take time
to explain the error messages, firing schedules and offered the prorated
prices on the elements.
But, I find it amazing that I purchased 2 kilns at the same time and they
both started having the very same problem with in a week of each other seven
months after the purchase. They were not both used in exactly the same manner
concerning the firing schedules and maybe they were fired 12 to 20 times at
cone six. The bottom line is that I have used several different kiln models
from different manufactures over a period of 15 years at this facility and
never experienced the problems that I encountered with these two kilns. In
fact one of my oldest kilns that I had was an L&L that was replaced with the
Dyna kiln. It functioned great and was probably over 10 years old and I might
add it was a manual kiln.
I guess what it really boils down to is getting back to basics. Potters have
been very successful for more than a half a century using the basic
technology that has existed in manual operated kilns. That's what I'll be
doing the next time I have been allocated funds to purchase a new kiln.
You did not respond to my question about your attendance at the large ceramic
trade show in February. The studio is in the same complex that the Expo
Center is that host that event. I would still like to meet you and possibly
show you the facility if you make the visit.
Thanks for your lengthy response.
Kim Lemonakis
Stephen J Lewicki on sat 19 jan 02
Kim -
The detailed answers I gave you in my posting are things that I have been
mulling over for some time. The questions that you raise involve
complicated answers and it is hard to provide that in a phone conversation.
Rob Battey, who I refered you to in our organization, spends all his time
doing this sort of thing. I'm not ashamed to say he knows more about the
detailed inner workings of our control than I do. That is why I refered you
to him.
As I said I was actually happy to have this opportunity to address these
questions in such a pulic and detailed way. I believe our customers and our
company are best served by education about the issues involved in design.
Good design is a question of 90% making the right compromises and 10%
creative inspiration. It is helpful to know why we make the compromises
that we do. I have the interesting experience of designing 1/4 million
dollar industrial furnaces. Even there the same idea applies.
I mentioned some of the tradeoffs with manual vs automatic kilns and I
could go into great detail on this subject if people are interested. We
sell both. Quickly I would say that the automatic kilns are more uniform,
offer more possibilities for creative expression (like slow cooling), are
less prone to overfiring and are more flexible. The manual kilns are less
complicated to understand and troubleshoot, easier to fix, cheaper to
operate (because you don't have to worry about thermocouple replacement)
and probably result in longer useful element life. Which is actually easier
to use is probably an individual thing.
By the way I am planning to visit the show in Florida (although we won't be
exhibiting) and I would love to meet you as well. Please email me your
address, phone and times you will be around.
Stephen J Lewicki
President
L&L Kiln Mfg., Inc.
steve@hotkilns.com
Susan on sun 20 jan 02
Dear Stephen,
I am impressed with your active participation and lengthy helpful
contributions to this list. Thank you.
I do have a few questions before I order my JD18-3 (with heavy duty
elements, industrial thermos, 3 inch bricks) kiln on Monday.
1. You mentioned that a J18 will work fine on a 30 amp circuit. Jonathan
Kaplan recommends I ask your company if I need to increase the 30amp
breakers since I am planning on ordering your heavy duty elements. Will
30amps be enough? I haven't had my electrician start work yet so I need to
know this beforehand.
2. Thank you for suggesting your filtered 120 volt power supply for just the
control circuit. Is this a standard item that Laguna Clay knows about so I
will be able to purchase it from them? If not, should I order it without and
pay L&L directly to install it before it is shipped?
3. Unfortunately I found out that Laguna Clay does not put together the kiln
sections, vent and dyno-trol control circuit...they just deliver. Can you
suggest companies in the Los Angeles area that are qualified to put it
together? I do not want to take the chance and do it myself. I read your
website regarding your vent which states that I would need to drill holes
into the bottom of the kiln to install the vent. Is this something that can
be done at your factory?
4. I plan on keeping my kiln outdoors in a metal garden shed. During the
winter season especially when it rains I would like to take the dyno-trol
indoors to protect it from moisture in the air (suggestion from Robert). If
I directly hook up the kiln, will this be possible or would I need to keep
the plug?
5. Lastly, when I order the vent and filtered 120 volt power supply I would
need to have a double outlet installed. What would be the amps used so the
electrician can determine an additional breaker for it?
Susan
p.s. I too was curious about the GFI because I only thought they are used in
bathrooms to prevent problems with water contact. My friend who is a
construction engineer said it is also used for power surges where a standard
breaker will shut down when it senses heat buildup...but a GFI will sense
outrages and surges. He said it is worth the few bucks as an insurance
against problems.
> From: Stephen J Lewicki
> Reply-To: Ceramic Arts Discussion List
> Date: Sun, 20 Jan 2002 21:26:16 -0500
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Re: L&L Kilns, Element Life, Automatic Controls, & Customer Service
>
> Susan -
>
> A J18 or JD18 (automatic) will work perfectly fine on a 30 amp circuit. It
> is not an underpowered kiln especially in a 240 volt version. The kiln in
> our line (and other ones out there of similar size - 23" diam by 27" high -
> and amperage- 45 amps) is the J230 especially in 208 volts. I explained why
> this is so in my lengthly posting the other day and also explained what our
> solution is (which coincides with Jonathan Kaplan's thoughts). The model
> JD230S has extra power and requires a 70 amp circuit- but there is no extra
> cost for this from us.
>
> But back to your question. Do get the heavy-duty elements, industrial
> thermocouples, 3" firebrick, and vent. The kiln does come with a 50 amp
> plug but you can easily remove this and direct wire the kiln to a fused
> disconnect switch if you prefer. Because that plug is so overrated for the
> amperage on this kiln I wouldn't be too concerned - but in any case it
> won't affect the kiln. I have never heard of anyone using a GFI receptical
> for a kiln but I, too, would be interested in other opinions on this.
> Typically those are used when you are around water. We do have an option
> which you might want to consider if you get power surges, line noise from
> motors, or outages. We have a filtered 120 volt power supply for just the
> control circuit. This way you can plug your control into a really good
> inexpensive computer surge protector or even UPS system while the main
> power for heating remains at 240 volts. It only costs $75.
>
> One other caution about what Jonathan Kaplan said. His idea requires
> careful implimentation. You can't just go in an increase the amperage of
> kiln without knowing what you are doing. I have talked to Jonathan before I
> I am quite sure is is fully competent to do this. All the wiring and
> components in all the circuits must be sized for the higher amperage. This
> is the case in the factory upgraded JD230S for instance. This model by the
> way is also UL listed. If you go and change the wiring on a kiln you will
> void the UL listing (which might be an issue with your insurer) and you
> could do someting dangerous unless you know what you are doing.
>
> Hope this helps.
>
> Stephen J Lewicki
> President
> L&L Kiln Mfg., Inc.
> 877-513-7869
> steve@hotkilns.com
>
> ______________________________________________________________________________
> 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.
>
John Hesselberth on sun 20 jan 02
on 1/19/02 5:53 PM, Stephen J Lewicki at STEVE@HOTKILNS.COM wrote:
> Quickly I would say that the automatic kilns are more uniform,
> offer more possibilities for creative expression (like slow cooling), are
> less prone to overfiring and are more flexible.
I want to zero in a little bit on this statement in Stephen Lewicki's recent
post.
If you are going to buy a new kiln in the near future and if you work at
cone 6 or thereabouts, I STRONGLY recommend you buy a computer-controlled
kiln. It just makes it so much easier to get the best out of your glazes.
You can do it manually, but controlling the cooling rate by turning the
switches on your kiln back down to medium or low is a nuisance at best. If
indeed, element life turns out to be a bit shorter it is a price well worth
paying. By the way, I haven't noticed this personally--I get quite good
element life on my computer-controlled L&L compared to the manual Skutt I
got rid of 3 years ago. I have 2 big difference vs. what I understand of
Kim's situation--I have a kiln vent and 240 volt service.
If you have some extra money to upgrade your existing equipment, put a
controller right on top of your wish list.
And Kim, in spite of your current unhappiness you will be delighted you
bought computer-controlled kilns within a year or two. You have purchased
very fine kilns--I'd give up a lot of things before I gave up my L&L.
Regards,
John
Web sites: http://www.masteringglazes.com and http://www.frogpondpottery.com
Email: john@frogpondpottery.com
"Art is not a handicraft, it is the transmission of feeling the artist has
experienced." Leo Tolstoy, 1898
Kim Lemonakis on sun 20 jan 02
Dear John:
Thanks for your input. In all the years that I've had to function in a
building with 208 service and not having the luxury of kiln vents, I faired
pretty well.
I have had Skutts, Crusaders, Olympics and L&L Kilns. They were all manual
and worked fine with normal use and wear and tear. I haven't kept accurate
records about replacing elements but I will say that it's never been after 7
months of use & that's my bone of contention. It sounds like your getting
more life out of your elements them I have.
In my daily life I could not exist without my PC but when it comes to
depending on a computer to baby-sit my kilns I'll take a manual any day.
It's my job as a potter to monitor and pay attention to what's happening in
the kilns. I guess I am from the old school, I have a 50 cubic foot down
draft car kiln that I don't dare walk away from for mote than an hour, so I
feel that it's part of the process to be actively involved with monitoring
the kilns.
After the problems occurred with the Dyna Kilns I checked into retro fitting
them with manual components, it was more than half the cost of the kilns. I
don't think in two years I'll feel any different then I do at this moment. I
am content to live with the technology that's been in existence longer than
I've been a potter.
Thanks again.
Kim
Susan on sun 20 jan 02
Hi John,
thanks for your input. I am a ceramic student at a local university and have
been saving up for an electric kiln so I can have more control on my firings
and have a way to keep the kiln cleaner. I was ready to purchase a L&L
JD18-3 (240) on Friday until I read Kim's horror story. I called up tech
support at L&L (great support line) and asked what exactly I needed to
purchase. (I already knew about the heavy duty elements and industrial
thermos I was told to get 3 inch bricks, a kiln sitter for my automatic
controls, a hand held remote control--- but they didn't mention purchasing a
vent. I just joined this discussion group Friday and am happy to read that I
will need to purchase a vent and I should get some sort of roof fan for my
outdoor metal shed.
Kim, L&L sells a "S" thermocouple that L&L calls their "very best
thermocouple for constant high fire applications". Perhaps that would help
your problem. You can read about it at their website.
I do have two questions...If I don't fire hotter than cone 5, how many
firings (average) can I expect to get without replacing elements? Is Kim's
experience common with L&L kilns? Should I expect to replace parts after a
dozen or so uses?
A construction engineer friend told me to have my electrician install a GFI
(ground fault interrupter) on the breaker in the electrical panel. Has
anyone done that for a 30 amp breaker? He suggested this because a normal
breaker senses heat and will shut down...but a GFI senses power surges and
will protect the kiln. I plan on getting a fused disconnect at the kiln
location but wonder if this is overkill. Any thoughts on this?
susan
> From: John Hesselberth
> less prone to overfiring and are more flexible.
>
> I want to zero in a little bit on this statement in Stephen Lewicki's recent
> post.
>
> If you are going to buy a new kiln in the near future and if you work at
> cone 6 or thereabouts, I STRONGLY recommend you buy a computer-controlled
> kiln. It just makes it so much easier to get the best out of your glazes.
> You can do it manually, but controlling the cooling rate by turning the
> switches on your kiln back down to medium or low is a nuisance at best. If
> indeed, element life turns out to be a bit shorter it is a price well worth
> paying. By the way, I haven't noticed this personally--I get quite good
> element life on my computer-controlled L&L compared to the manual Skutt I
> got rid of 3 years ago. I have 2 big difference vs. what I understand of
> Kim's situation--I have a kiln vent and 240 volt service.
>
> If you have some extra money to upgrade your existing equipment, put a
> controller right on top of your wish list.
>
> And Kim, in spite of your current unhappiness you will be delighted you
> bought computer-controlled kilns within a year or two. You have purchased
> very fine kilns--I'd give up a lot of things before I gave up my L&L.
>
> Regards,
>
> John
> Web sites: http://www.masteringglazes.com and http://www.frogpondpottery.com
> Email: john@frogpondpottery.com
>
> "Art is not a handicraft, it is the transmission of feeling the artist has
> experienced." Leo Tolstoy, 1898
>
> ______________________________________________________________________________
> 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.
>
John Hesselberth on sun 20 jan 02
on 1/20/02 11:22 AM, Susan at sgraphic@MAIL.INSTANET.COM wrote:
> I do have two questions...If I don't fire hotter than cone 5, how many
> firings (average) can I expect to get without replacing elements? Is Kim's
> experience common with L&L kilns? Should I expect to replace parts after a
> dozen or so uses?
>
> A construction engineer friend told me to have my electrician install a GFI
> (ground fault interrupter) on the breaker in the electrical panel. Has
> anyone done that for a 30 amp breaker? He suggested this because a normal
> breaker senses heat and will shut down...but a GFI senses power surges and
> will protect the kiln. I plan on getting a fused disconnect at the kiln
> location but wonder if this is overkill. Any thoughts on this?
Hi Susan,
I will be interested to hear what others say in response to your questions.
My own answer on element life is that there are too many variables involved
to give you any kind of reliable estimate. For example how heavily are you
going to load your kiln--heavier loads require more energy (and more wear
and tear on your elements) per firing. Are you going to burn off lots of wax
or none--burning off organic materials can be hard on elements. Will the
kiln be vented--we've already discussed that. Are you going to turn the
kiln off at maturity and fast cool or fire down--that too will affect
element life. I could go on, but I think you get the picture. My own
practice is to buy a new set of elements to have on hand about 6 months
after I installed the last set, but I don't fire my big kiln very often so
they sit on my shelf for a year or two after I buy them. A dozen firings is
definitely too few though. I think the range is probably more like
50-100--maybe more--at cone 6.
I'll beg off on the GFI question, but somehow it doesn't seem like a needed
thing to me--I've never had one in a kiln circuit. What I have found to be
important is direct wiring (at least with my 60 amp circuit) rather than
using the plugs. I think it goes without saying that the plugs will arc and
cause problems with a circuit that big over time. I never had that problem
with my old 30 amp kiln.
Regards,
John
web sites: http://www.masteringglazes.com and http://www.frogpondpottery.com
EMail: john@frogpondpottery.com
"Pots, like other forms of art, are human expressions: pleasure, pain or
indifference before them depends upon their natures, and their natures are
inevitably projections of the minds of their creators." Bernard Leach, A
Potter's Book.
Ceramic Design Group on sun 20 jan 02
on 1/20/02 10:39 AM, John Hesselberth at john@FROGPONDPOTTERY.COM wrote:
> on 1/20/02 11:22 AM, Susan at sgraphic@MAIL.INSTANET.COM wrote:
>
>> I do have two questions...If I don't fire hotter than cone 5, how many
>> firings (average) can I expect to get without replacing elements? Is Kim's
>> experience common with L&L kilns? Should I expect to replace parts after a
>> dozen or so uses?
We have replaced all stock elements in our older kilns with upgraded heavy
duty elements from Euclid's Elements/Pottery Supply House in Canada. All our
kilns are computer controlled, vented, 240 volts and fire regularly to cone
6 and everywhere in between. My record keeping does include dates of element
replacements. We have well over 3 years of firings on 2 kilns that fire 3-5
times/week. Our large front loading kiln is 2 years old and fires 2x/week.
These kilns are used for bisque, glaze, decals, etc. and other than some
wear and tear on the top row of bricks for the top loaders, are in
relatively good shape considering their age, 9 years!
I certainly can't speak for others and their kiln/element usage and life
span, but from some of the stories on the list, I would certainly suggest
that upgrading the factory elements is a very good starting point. Knowing
full well that most of the top loading kilns are under powered and under
insulated, you can take responsibility and upgrade the elements. You will
need a higher rated breaker, and check with an electrician to make sure that
the feed wires to the kiln are of proper sizing for the increased amperage.
Spending the extra money beats whining and complaining any day!
Jonathan
Jonathan Kaplan, president
Ceramic Design Group
PO Box 775112
Steamboat Springs CO 80477
voice and fax 970 879-9139
info@ceramicdesigngroup.net
Plant Location:
1280 13th Street Unit 13
Steamboat Springs CO 80487
(please use this address for all deliveries via UPS, comman carrier, Fed Ex,
etc.)
"Custom design and manufacturing for the ceramic arts, giftware and pottery
industries. Molds, models, and tooling for slip casting, jiggering and
hydraulic pressing. Consultation on clay and glaze formulation, production
systems,firing, and kilns.
Susan on sun 20 jan 02
> I'll beg off on the GFI question, but somehow it doesn't seem like a needed
> thing to me--I've never had one in a kiln circuit. What I have found to be
> important is direct wiring (at least with my 60 amp circuit) rather than
> using the plugs. I think it goes without saying that the plugs will arc and
> cause problems with a circuit that big over time. I never had that problem
> with my old 30 amp kiln.
>
> Regards,
>
> John
Hi John,
I talked to Robert (tech support) at L&L and he told me that a 30amp does
not have to be direct wired because the cord and plug is gauged for 50amp.
He did say not to plug and unplug it often to prevent the prongs from
loosening. In fact, on their webpage link of "pre-order and pre installation
checklist", they recommend direct wiring on all kilns bigger than J230 and 3
phase. The kiln I want to order is a JD18-3 and is smaller than the size
they recommend to direct wire. Since my kiln will be outdoors, during
raining season, I plan on taking the controls indoors so for now I would
like to keep the plug.
Regarding if my kiln will withstand the average amount of firings, I am
planning on experimenting with decals and the covercoat could discharge
fumes. Thanks for the advice on waxes, (I won't use them now) I usually use
latex to "wax" dry foot my pieces. Hopefully with a vent, the toxic
chemicals will vent out and prevent the elements from failing.
I am curious if anyone has used a GFI though...It is not attached to the
kiln but to the electrical panel. I feel with a fused disconnect, perhaps a
GFI is not needed.
susan
Susan on sun 20 jan 02
> I certainly can't speak for others and their kiln/element usage and life
> span, but from some of the stories on the list, I would certainly suggest
> that upgrading the factory elements is a very good starting point. Knowing
> full well that most of the top loading kilns are under powered and under
> insulated, you can take responsibility and upgrade the elements. You will
> need a higher rated breaker, and check with an electrician to make sure that
> the feed wires to the kiln are of proper sizing for the increased amperage.
>
my gosh! Tech support at L&L never told me that! The L&L J18 uses 23amps and
recommends a 30amp breaker. I plan on getting the 3 inch brick, industrial
thermo and upgrading the factory elements to their heavy duty elements. L&L
doesn't mention upgrading the amps. I've even asked on the phone. What size
would you recommend for this size kiln?
susan
Ceramic Design Group on sun 20 jan 02
on 1/20/02 1:56 PM, Susan at sgraphic@MAIL.INSTANET.COM wrote:
>> I certainly can't speak for others and their kiln/element usage and life
>> span, but from some of the stories on the list, I would certainly suggest
>> that upgrading the factory elements is a very good starting point. Knowing
>> full well that most of the top loading kilns are under powered and under
>> insulated, you can take responsibility and upgrade the elements. You will
>> need a higher rated breaker, and check with an electrician to make sure that
>> the feed wires to the kiln are of proper sizing for the increased amperage.
>>
> my gosh! Tech support at L&L never told me that! The L&L J18 uses 23amps and
> recommends a 30amp breaker. I plan on getting the 3 inch brick, industrial
> thermo and upgrading the factory elements to their heavy duty elements. L&L
> doesn't mention upgrading the amps. I've even asked on the phone. What size
> would you recommend for this size kiln?
>
> susan
I am not an electrician and I don't play one on TV, but we have #6 wires
from the kiln to the connection boxes. All our kilns are direct wired and
use copper split bolts to connect the kilns to the supply.
Please Please Please check with your electrician before upgrading your
elements. Ask L and L what size breaker they recommend and what size wiring
to the kiln for their heavy duty elements. From reading Steve's post from
Land L, they are informative, accurate and easy to work with. In fact, years
ago when I had a pottery facility in Pennsylvania, we had 2 J230 kilns with
kiln setters and infinite switches. These kilns were work horses for years
and years. Even after a pipe burst and filled BOTH kilns with water, after
drying out and firing on low for a few days, they worked fine. While I have
not had any recent experience with them, they seem like a very good company
with knowledgeable people to work with.
Jonathan
Jonathan Kaplan, president
Ceramic Design Group
PO Box 775112
Steamboat Springs CO 80477
voice and fax 970 879-9139
info@ceramicdesigngroup.net
Plant Location:
1280 13th Street Unit 13
Steamboat Springs CO 80487
(please use this address for all deliveries via UPS, comman carrier, Fed Ex,
etc.)
"Custom design and manufacturing for the ceramic arts, giftware and pottery
industries. Molds, models, and tooling for slip casting, jiggering and
hydraulic pressing. Consultation on clay and glaze formulation, production
systems,firing, and kilns.
Jonathan
Stephen J Lewicki on sun 20 jan 02
Susan -
A J18 or JD18 (automatic) will work perfectly fine on a 30 amp circuit. It
is not an underpowered kiln especially in a 240 volt version. The kiln in
our line (and other ones out there of similar size - 23" diam by 27" high -
and amperage- 45 amps) is the J230 especially in 208 volts. I explained why
this is so in my lengthly posting the other day and also explained what our
solution is (which coincides with Jonathan Kaplan's thoughts). The model
JD230S has extra power and requires a 70 amp circuit- but there is no extra
cost for this from us.
But back to your question. Do get the heavy-duty elements, industrial
thermocouples, 3" firebrick, and vent. The kiln does come with a 50 amp
plug but you can easily remove this and direct wire the kiln to a fused
disconnect switch if you prefer. Because that plug is so overrated for the
amperage on this kiln I wouldn't be too concerned - but in any case it
won't affect the kiln. I have never heard of anyone using a GFI receptical
for a kiln but I, too, would be interested in other opinions on this.
Typically those are used when you are around water. We do have an option
which you might want to consider if you get power surges, line noise from
motors, or outages. We have a filtered 120 volt power supply for just the
control circuit. This way you can plug your control into a really good
inexpensive computer surge protector or even UPS system while the main
power for heating remains at 240 volts. It only costs $75.
One other caution about what Jonathan Kaplan said. His idea requires
careful implimentation. You can't just go in an increase the amperage of
kiln without knowing what you are doing. I have talked to Jonathan before I
I am quite sure is is fully competent to do this. All the wiring and
components in all the circuits must be sized for the higher amperage. This
is the case in the factory upgraded JD230S for instance. This model by the
way is also UL listed. If you go and change the wiring on a kiln you will
void the UL listing (which might be an issue with your insurer) and you
could do someting dangerous unless you know what you are doing.
Hope this helps.
Stephen J Lewicki
President
L&L Kiln Mfg., Inc.
877-513-7869
steve@hotkilns.com
Stephen J Lewicki on mon 21 jan 02
Dear Susan -
Although I answered this in yur private email this morning I thought I
would sumerize the answers in this forum for those who are following this
discussion.
1) The heavy-duty element option does not increase the power requirements
of the kiln. It mearly uses thicker gauge wire and a larger diameter coil
which allow us to improve the overall element surface temperature and the
ability of the element to stand up to oxidation and degradation over time.
The coils are the same resistance as our standard elements so the power of
the kiln stays the same.
2)The 120 volt filtered power supply is a standard option listed in our
catalog.
3)We can drill the holes for the vents. The kilns are very easy to put
together although the Easy-Lift hinge does take more assembly and expertise
(there is an assembly instruction sheet that you can download on our PDF
library). In any case, while nice for the 23" diamter kilns it is a real
luxury for the the 17-1/2" diam kilns.
4)I recommend you keep the cord so you can easily remove the panel anytime
(as you are planning for storage).
5) the amp draw of the control system is a few amps at most and the vent
only draws 1.37 amps. Astandard double 15 amp receptical is fine.
Stephen J Lewicki
President
L&L Kiln Mfg., Inc.
877-513-7869
steve@hotkilns.com
Nanci Bishof on mon 21 jan 02
The GFI is probably to protect the computer rather than the kiln. It serves
as the surge protector that we put on our desktop computers.
nanci
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