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What Kind Of Kiln Shelves To Use?

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#1 ShellHawk

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Posted 27 December 2013 - 05:36 PM

It looks like, at long last, I can upgrade to a Skutt electric kiln with all the digital doohickeys I've been craving for so long. (Yay, me!) I'm wondering about what kind of kiln shelves I should consider investing in. The Skutt will go up to cone 10, and though I don't anticipate going to that cone quite yet, I will be, so I want shelves that will endure that kind of heat.

 

I've heard of silicon carbide shelves and that they're lighter and are supposed to be stronger, but I don't know anything else about their durability or performance.

 

Pros and cons of various shelf choices are appreciated!

 

Thanks!



#2 Mark C.

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Posted 27 December 2013 - 05:49 PM

!st let me say consider an L&L kiln over a Skutt (I own a few Skutts) and the L& L cost a little more but are well worth that upfront cost on so many levels-especially on the high temps side of things with their element holders. I wish I bought one over any of my skutts. They are better made all around.

get a quote from Neil on this board

www.neilestrickgallery.com

Ok-that said the best shelves for high fire are advancers but they cost more than you want to spend-if you fire a lot they pay for themselves .They are super thin (a tad over 1/4 inch) and will NEVER warp

The second best option are the corelite shelves-they look honey combed on the inside and will hold up well and are a bit lighter

they look like this

http://www.baileypot...liteshelves.htm

Mark


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#3 neilestrick

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Posted 27 December 2013 - 06:58 PM

I love the Core-Lite shelves. Light and very strong yet still affordable. You can get Advancer silicon carbide shelves that are super thin and super strong but they will cost 4 times as much or more.

Thanks Mark. Shellhawk let me know if you need any L&L info.
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#4 Mark C.

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Posted 28 December 2013 - 12:29 PM

Corelites can warp over time (I just got a pm on this  from someone as they fire a few times per week to cone 5.5 and 25 of them have slumped)I di not know if they are 1/2 or full shelves?

Advancers never warp take less space and if you fire every week will pay for themselves in space saving quickly.

Yes they can conduct electricity but that's easy to load them from touching any elements-your element really should be in the groves of the kiln bricks anyway.

Mark


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#5 JBaymore

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Posted 28 December 2013 - 12:41 PM

I'm with Mark on this one as to the value of Advancers. 

 

While Advancers will certainly give you a bad case of sticker shock, there are SO many benefits with them.  THAT is one reason they are expensive....... they are good.  You get what you pay for.  There is a reason industry has gone over to fiber kiln linings and this kind of low mass furniture; savings in firing costs.  Less heat energy to heat up the kiln and furniture in periodic kilns.  Plus more ware in the kiln.

 

Loading these light shelves into a top loading electric kiln is a JOY!  Lifting them at arms length over my head into the back stacking of the norborigama chambers without straining at all is like the credit card commercials.... priceless!

 

Wood ash in a wood kiln comes right off them.  As do glaze drips.  The stay laser level flat.  They hold a TON of weight.  They take up so much less storage room.

 

The one BIG downside is DON"T GET THEM WET and then fire them very quickly.  They don't crack... they EXPLODE!  (Been there, done that, bought the T-shirt.) 

 

If you can make the capital expenditure work, they WILL pay for themselves pretty quickly if you are doing a lot of firing.  But if you fire very infrequently...... do the math before jumping in.  You might not see a payback for years and YEARS.

 

This is yet one more case where the right answer for one person is not the right answer for another.  It takes some serious analysis.

 

best,

 

.......................john


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#6 Chris Throws Pots

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Posted 28 December 2013 - 12:45 PM

All my Corelites have warped badly. If you're willing to go without kiln wash, buy a set of Corelites and save the money (and potential hazards... see Norm's response) you'd spend on the Advancers. Just mark the shelves A side and B side with RIO wash and alternate which side is up. I fire to cone 6 at least once a week, but in my community studio there are enough mishaps that I won't skip the kiln wash. Hence I can't flip my shelves without either totally grinding them or risking kiln wash falling into the wares. I've seen warping in the Corelites as quickly as 10 or 12 firings, so I've stopped buying them and have switched back to high alumina shelves. Which also warp but are much cheaper.

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#7 ShellHawk

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Posted 28 December 2013 - 02:29 PM

Thanks for the input, and please keep it coming!

 

The main reason I have not considered an L & L kiln is because my teacher (who shall remain nameless, but he's well known in the ceramics world as someone who knows his stuff) told me he repeatedly had terrible experiences with their customer service department. He bought one for the community college where he teaches, had trouble with it from the start, and customer service could have cared less. Had he been the kind of guy who would say, "Don't you know who I am?" he probably would have gotten the service he should have received in the first place, but he's not "that guy." (Which is why I like being his student!  :) )

 

That bothers me, to say the least.

 

I do like the ease of changing elements, for certain. I'm not a mechanic, so the easier, the better!

 

More input is greatly appreciated!



#8 ShellHawk

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Posted 28 December 2013 - 03:51 PM

My experience with Cress is not that they don't care, but more that they don't actually know.  Have you ever tried to learn about hardware at a Home Depot?

 

The electrical engineers or electricians who design these kilns are very unlikely to be full-time employees of the kiln maker.

 

When I've had questions with the Bartlett controller I initially called Cress, who would relay my question with a certain degree of accuracy to Bartlett and then with additional translation errors Cress provided me with Bartlett's answer.  Now I just call Steve or Jane directly at Bartlett.  Sometimes the "customization" of the Bartlett v6-CF means that neither party really has a firm answer - another reason to prefer the standard Bartlett V6-CF.

 

Plus, many of these kiln makers have been sold or moved several times.  I asked Art Maldanato at Cress whether he had any idea how long ago a very old Cress kiln was manufactured.   He replied he couldn't be sure it was actually a Cress kiln, which is probably an accurate answer.  I'm sure it's a Cress kiln, but the people who know when it was made are probably dead.

 

We have a very old Brent slab-roller.  Unfortunately Robert Brent was a potter rather than an engineer.  One of his many odd little quirks was using soft-iron machine screws rather than hardened stainless steel.  Why?  So he could hand stamp the top of the screws with RWB.  That's an artist working outside of his field of expertise.  You'll find a lot of that sort of thing at kiln manufacturers.

 

 

P.S. When pricing kilns, you'll discover that shipping can be a significant part of the total cost, which is the reason kiln makers are more popular in their local region than in other areas.

 

P.S #2  If your kiln maker offers a stainless steel upgrade for an extra $300 or less, it will be the best money you ever spend.

 

Thanks for the input, and please keep it coming!

 

The main reason I have not considered an L & L kiln is because my teacher (who shall remain nameless, but he's well known in the ceramics world as someone who knows his stuff) told me he repeatedly had terrible experiences with their customer service department. He bought one for the community college where he teaches, had trouble with it from the start, and customer service could have cared less. Had he been the kind of guy who would say, "Don't you know who I am?" he probably would have gotten the service he should have received in the first place, but he's not "that guy." (Which is why I like being his student!  :) )

 

That bothers me, to say the least.

 

I do like the ease of changing elements, for certain. I'm not a mechanic, so the easier, the better!

 

More input is greatly appreciated!

 

Had he been the kind of guy who would say, "Don't you know who I am?"

 

Trust me, the person he's dealing with at any kiln manufacturer almost certainly didn't know who he is, even if he had spelled his name correctly and cited his exhibits and journal articles.  Art appreciation is a very high level of expectation for somebody employed in a minimum-wage job.  It would be like chef Alice Waters hoping to be recognized at a McDonalds.

I think his issue was with the attitude, not ignorance. Several different people (if I remember right, which I may not be!) had a solid attitude of "I don't care." 

 

I have a hobby-level Cress and I like it. It's been a little workhorse! It's just time for a "grownup" kiln, and one that I can fit into my space and not have to upgrade my electrical. (I've been quoted $5000.00 to run another line out to the garage, and then they don't call me back because the job is too small  :wacko:, so I need to stick with my current 220 [get it? current? LOL])

 

I'll look into the L & L some more. I haven't had the experience of elements popping out of place, so that's a "fun fact" to take into consideration! I'll do some research on the Advancers, too, just out of curiosity.



#9 JBaymore

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Posted 28 December 2013 - 03:55 PM

 

Mark / John - How well do Advancers conduct electricity?

 

If elements pop-out during a firing, will it pop the circuit breaker or do the shelves themselves simply become heating elements from one side of the kiln to the other?

 

Never tested the Advancer shelves; no reason to do so.  But silicon carbide is used for elements in certain types of electric kilns.  Sometime called "glo-bars".

 

In order for there to be any "conducting of electricity" (current flow) there has to be a path to a ground.  So you can take a silicon carbide shelf and butt it right into the elements IN ONE SPOT, and aside from likely damaging the elements there .....no electricity will flow through the shelf itself. Electricity basics 101. 

 

However, if you have one part of the shelf touching a powered up element,...........  AND you then stand on a damp concrete floor in your bare feet......... and you then touch some part of the shelf .. ......... there is a path to ground possible......... through the shelf, through your body and then to the floor.  Then we get into the potential resistacne equations to see if the current flow will be enugh to stop your heart, or just give you a major league ZAP.

 

There is no issue to this business than the lawyers talking.  IF someone did this...... they COULD get electrocuted.  Yes.  It is like the warnings on the plastic bags that tell you not to place them over your head, and the stuff on McDonalds coffee cups that explain that the coffee is hot.

 

Yes... there could be an issue.  It likely woyuld be experienced by one of the Darwin Award contendees.

 

best,

 

........................john


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Professor of Ceramics; New Hampshire Insitute of Art

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#10 ShellHawk

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Posted 28 December 2013 - 05:13 PM

 

 

Mark / John - How well do Advancers conduct electricity?

 

If elements pop-out during a firing, will it pop the circuit breaker or do the shelves themselves simply become heating elements from one side of the kiln to the other?

 

 

 

 

 

There is no issue to this business than the lawyers talking.  IF someone did this...... they COULD get electrocuted.  Yes.  It is like the warnings on the plastic bags that tell you not to place them over your head, and the stuff on McDonalds coffee cups that explain that the coffee is hot.

 

Yes... there could be an issue.  It likely woyuld be experienced by one of the Darwin Award contendees.

 

best,

 

........................john

 

Wait, wait, wait!

 

You mean you can't put plastic bags over your head?!

 

Wow! I wish I'd signed up for these forums sooner! LOL  ;)



#11 Mark C.

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Posted 28 December 2013 - 05:31 PM

Shellhawk thats just a sample size of 1 as far as L&L-I have heard the other side of that from many a happy owners.

The skutts are just not as much quality from the start and with time you will see this. I have in the past 40 years.

You just will get a better product from the start-like Norm says in his post as soon as you change ouyt the elements once you will see this. 

Norm I fire about 50 advancers in two gas kilns so I cannot anwser the electric part other tthan I have a friend with a cone 10 skutt electric who loves his electric advancers with zero issues other than wishing he had a L&L instead.

Advancers make the most sense as John says especally in the long run  but for a hobbiest I doubt it.

Mark


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www.liscomhillpottery.com

#12 JBaymore

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Posted 28 December 2013 - 09:35 PM

 

I'm curious what happens when a Silicon Carbide shelf touches an element which pops out of one side and touches a different element which pops out on the other side.  It's essential to know what the potential down-side is - even though it doesn't seem likely.

 

 

So both elements when powered up are supplied with voltage from the same source and are operating to the same ground.  Let's assume here something like 208 VAC.  So the hot side first element has a voltage of 208 V above nominal ground.  If the second element is powered also, it is also sitting at 208 V above ground.  Since both elements are at the same potential above common ground, no current will flow.  So nothing will happen (other than possible physical damage to the elements at the points of contact).

 

But let's say that the first element is powered up at the time, and the second element is on an "off" duty cycle (as in a zone control type kiln might be).  Element 1 is at 208 V.  Element 2 is at 0 V..... but.. and this is where the "but" come in... it dependes on how the contactors for the specific kiln break the circuit.  If they completly break both poles of the supply circuit, then there is no path to ground again even though the is no potential on element 2.  It is "floating".  What then happens is that if there is a path to ground from that second element ... then current will flow.  BUT the amount will be determined by the total resistive and reactive resistance of BOTH the elelments from the source on element 1, plus the shelf, plus the element 2 to to bount of w hatever ground is "made". 

 

I don't have resistance numbers for the Advancer material.  I bet it is high.  Most glo-bar type kilns use 440V to power them.

 

Worst case is likely that the kiln's breaker should blow if the current gets too high.

 

I think in almost all, if not all, cases, lacking a human being getting their body in the way to run current to ground, it is not going to cause any issues.  Plus you'd have to work at having a proper sized shelf set in such a way that even elements "popping" out of the grooves would contact two separate elements at the same time.  If it was cocked to one side..... then it'd be further from the other.  If it was the correct size shelf to start with, there'd be good clearance from the banks of elements....... the kiln would have to be in really bad repair to have that situation develop then....which would be "operator error" to let it get to that level of disrepair.

 

 

 

BTW.... I would have thought the local breaker on your kiln should have blown, not the main somewhere else. 

 

best,

 

....................john


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Professor of Ceramics; New Hampshire Insitute of Art

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#13 ShellHawk

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Posted 28 December 2013 - 09:58 PM

Three phase is flat out not an option, and I'm just a regular person who owns her own home. I have to stick with single phase, which is obviously going to come into play during firings. I need to re-check my amperage because I just can't recall off the top of my head, and neither can hubby. I am lucky in that I recently got a job as an admin in a construction company, so get the "friend" discount on electrical, but obviously that depends on what kind of upgrade I'm talking about.

I'll check on amperage and re-post.

And thanks for all the input. These are things I need to take into consideration!



#14 atanzey

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Posted 28 December 2013 - 10:17 PM

I bought a used L&L, and immediately dealt with their service to get new elements, some replacement bricks and element holders.  I found them to be helpful.  Maybe not 'southern friendly' but I got everything I needed with a minimum of effort.  The support information on their website is the best I've found, although I haven't cruised 'all' the manufacturer's sites, since I really wanted the L&L.  I also have an Olympic gas, and a Cress test kiln.

 

Alice



#15 Mark C.

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Posted 28 December 2013 - 10:36 PM

After owning 3 skutts over a 40 year period I feel they are always playing catch up to other manufactures and use some questionable materials_ used to feel great about them untill things went south

To drive this home 2 of my skutt outer jackets have rusted badly-one has not -all are in same area all kept dry as a bone

The tension bands holding the outer jackets have all broken at the spot wields and needed repairs

All the screws on outside are cheap steel and rust away along with lid handles-Foe another 2$ per kiln these could all be stainless and last forever.

The plug system on the old kilns was a poor design and given up so parts are no longer avaiable for old kilns

I'm only on the outside still not even on the wiring yet-

OK skutt rant over

 

L& L are engineeered for easy of service and long life-yes they cost more but I bet they last longer-I know looking at one they are better made.

Mark


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#16 DirtRoads

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Posted 28 December 2013 - 11:44 PM

Kiln Shelves:  I have those Advancer shelves ... "At only 5/16” thick, ADVANCER® silicon nitride-bonded silicon carbide kiln shelves are 19 times stronger and weigh 50% less than conventional ram pressed ...

 

A good business decision.  They do cost more ... but do not wrap like those other kind.   I have  about 20 of those other ones that have warped.    They cool quicker (faster kiln turn around).  AND I can get one more shelf of goods.  So with my production schedule that's $80 more x 4 times a week... $320 a week   $1480 a month more in goods... the shelves have paid for themselves.

 

I have a L&L Eq2827-3 Equad-Pro Production Kiln purchased in June 2012.  Have used 2 sets of thermocouples.  Still using the original elements  (over 300 firings).  But these are no ordinary elements.   I've found the company to be very nice.    Couldn't ask for better service.   They replaced my thermocouples for free ... even though I had exceeded the average firings (warranty is based on time .. but I was firing 4-5 times a week and warranty was stated in time versus # of firings).  They were so nice about this .. I've bought additional ones and won't ask them to replace them again because I want to be fair.  I'm thankful to L&L for the quality product that has made my life easier.    Only thing .. they should put that # of firings on warranty instead of the 3 years.  

 

YES to Advancer kiln shelves and YES to L&L.



#17 ShellHawk

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Posted 29 December 2013 - 11:43 AM

If money and space weren't a factor (let's go, lottery!) I would get a Bailey front loader. No lotto money as of yet, though!

 

I was also thinking of the Skutt because of the KilnLink app you can get for the iPhone to check on your firing if you're away from home. I'm somewhat surprised to hear the consensus on their kilns, though.



#18 MikeFaul

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Posted 29 December 2013 - 01:02 PM

I love the Core-Lite shelves. Light and very strong yet still affordable. You can get Advancer silicon carbide shelves that are super thin and super strong but they will cost 4 times as much or more.

Thanks Mark. Shellhawk let me know if you need any L&L info.

Ditto on the Core-Lite shelves... We switched to these and have been very happy with them. I find them an excellent compromise between standard and the Advancer mentioned above.



#19 MikeFaul

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Posted 29 December 2013 - 01:06 PM

It looks like, at long last, I can upgrade to a Skutt electric kiln with all the digital doohickeys I've been craving for so long. (Yay, me!) I'm wondering about what kind of kiln shelves I should consider investing in. The Skutt will go up to cone 10, and though I don't anticipate going to that cone quite yet, I will be, so I want shelves that will endure that kind of heat.

 

I've heard of silicon carbide shelves and that they're lighter and are supposed to be stronger, but I don't know anything else about their durability or performance.

 

Pros and cons of various shelf choices are appreciated!

 

Thanks!

 

I'm very happy with my Skutts. I just added a third one to our collection. We did upgrade the elements in the production kilns. We fire to cone 6 using a modified ramp / hold schedule. One thing, if you're using the programed cone fire be sure to run test fires. We found some issues with over firing and had to call Skutt and have some offsets programmed into the standard programs to compensate. All-in-all it took only a few short minutes to fix. I've found their service to be very good as well.



#20 MikeFaul

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Posted 29 December 2013 - 01:17 PM

However, if you have one part of the shelf touching a powered up element,...........  AND you then stand on a damp concrete floor in your bare feet......... and you then touch some part of the shelf .. ......... there is a path to ground possible......... through the shelf, through your body and then to the floor.  Then we get into the potential resistacne equations to see if the current flow will be enugh to stop your heart, or just give you a major league ZAP.

 

best,

 

........................john

 

Hmmm... perhaps the concrete floor should be dampened with salt water while an electrical cord, wires bare at one end and divided, one end in your month and the other held under your arm pit is plugged into the wall while you cluck like a chicken...

 

Bet that would make your feathers fly...

 

NOTE TO SELF AND CHILDREN:  DO NOT TRY THIS WITHOUT WRITTEN PERMISSION FROM MOM, DAD, MEDICAL DOCTOR AND FIFTY ELECTRICIANS. :-)







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