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Member Since 08 Aug 2013
Offline Last Active Feb 04 2017 02:58 PM

Posts I've Made

In Topic: Fractured Kiln Shelves...

04 February 2017 - 02:58 PM

Given the scenario you are giving...................


I'd be looking at how the shelves in question were stored BEFORE you received them.  Were they all in one shipment?  Were they all tat the distributor before you go them or shipped direct from the manufacturer?


To me this sounds like either an original manufacturing defect, or a defect caused by the way the shelves were handled in storage or shipping. 


How do you STORE the shelves in your studio?


Failures happening in too large a range of conditions.





I have no idea how they were stored before they got to me. From what I can tell, the distributors don't stock Corelites, they order them and have them delivered to them or drop shipped to us. I can't speak to how they may have been stored before I received them. We store them on their edge up against the wall in the kiln room. That was up and until recently, I added a set of padded hooks on the walls in the kiln room, now they are stored on the hooks / on their edge up against the wall to keep them off the floor.

In Topic: Fractured Kiln Shelves...

04 February 2017 - 02:53 PM

I use 1/2 shelves in my large 1227 but I only bisque in them.

I know a tile company in New Mexico (silver city) that fires every day to glaze temps in Skutt 1227. This should not affect the shelves.

They fire one day unload the next and reload and fire that day and so on.

The 3 point stand is standard

Not sure how a load can shift?can you explain this?

any other new things? like new stilts?When you get a new shelve run it thru a bisque cycle 1st before the high fire.

Make sure 100% posts all line up  from floor to top shelve.-sound like you have done this.


We only use 1/2 shelves when we are firing off size wares like large vases or flower pots. That's only about 5% of our time...


When the shelf split, the fracture ran between two of the three post stacks. As it turns out it also ran between cups. The cups along the fracture weighed it down and caused it to fall toward the center of the kiln along the fracture. This resulted in one of the posts sliding into the fracture, which in turn caused the entire stack to list to the back of the kiln. The cups at the top of the kiln slid down the shelf along the plane of the now tilted stack. The ones closest to the edge slipped to the edge, which was in contact with the kiln wall, and came to rest against the kiln wall. So the load shifted based on a chain reaction.


Yes, Advancers are absolutely under consideration. Even if I have to buy a two or three a month...


Yes, we temper all of our kiln furniture at bisque.


Yes, we did just buy a new set of posts / stilts for the shelves. These were in use in all incidents where the shelves fractured. In all but one firing, they were above the point of fracture.


We use to use 1/2 shelves, but stopped using them to reduce the number of posts and increase the number of pots per shelf.

In Topic: Fractured Kiln Shelves...

04 February 2017 - 12:33 PM

@Mike, if you are still checking this thread, possibility of getting those shelves replaced from manufacturer. I sent you a pm with some details of what they told me about that. 




I have my distributor working on replacements... As an update, we have now lost an additional five 26" Corelite shelves.That's a total of seven fractured shelves in the last ten days. The situation is a bit out of control. I've contacted our distributor and they are contacting Standard who wholesales them for Resco. I've also sent an email to tech support at Resco. 


Here are my new observations:

  • Shelves are now splitting in glaze (^6) and bisque (^05) fires in addition to the fast ^10 fire mentioned at the top of the thread,
  • I pulled all the shelves, vacuumed the kilns, leveled each spacer, put in a flat shelf on the bottom, and checked for level, and then we lost the additional 5 shelves.
  • I believe 4 out of 5 of these shelves were about 90 days old and had less than 20 to 25 firings on them.
  • The new floor shelf is supported by three spacer posts (1.5" x .5") in a triangular pattern. 
  • All kiln stacks were built over top of the spacer posts.
  • Shelves are fracturing in multiple kilns,
  • I tested all elements and ran diagnostics on the kilns, they are working fine,
  • Cooler fires tend to produces fractures along multiple axises, hotter fires along one axises nearly dividing the shelf in two pieces.
  • On the last glaze, the load shifted and one cup slid into the kiln wall. It WAS NOT fused to the fire brick. (Shelves splitting on the cool down?)
  • I checked dates and all of this started 3 days after we increased our firing frequency to near daily to clear a few large orders we are processing. We started firing the kilns 5 or 6 times a week.
  • Each shelf was loaded with approximately 30 to 33 cocktail cups, each cup weights about .75 - .85 lbs.



Could the rigors of firing near daily have an affect on the shelves?

Alternative shelves to consider for production environment?

In Topic: Fractured Kiln Shelves...

16 January 2017 - 03:10 PM

Mike In ceramics often things work until (even thought not done right) until one pushes the limit -such as your fast fire.

It does matter that all posts are under one another from the floor to the ceiling. You may get away with this for years but sooner or later it will get you .

Wadding is EPK and alumina hydrate mixed 50% 50% with a little water.

next time make sure all pots including under floor all always lined up-the wadding as on under floor pots only to level. fire the 1st time a bit slower to dry wadding .

I will speak to your pots layout only after I know what you use above that full shelve ? all full shelves or some 1/2 shelves??


We use full rounds all the way up the stack. We use to use halves, but when I'm firing a full load of Rocks cups, I need every single cubic inch I can get. We use a 3 post arrangement between shelves. In bisque I allow a 1/2" space between the rim and the bottom of the next shelf, except when I get to the thermocouple. I make sure there we have enough vertical space to provide 2" of clearance on all sides of the thermocouple. 

In Topic: Fractured Kiln Shelves...

16 January 2017 - 03:04 PM

Is the shelf always the bottom shelf? Could it have been warped before the fast firing? I'm thinking if there were additional supports under the shelf, which must be the case or the shelf would have dropped, then an uneven support would add to the stress on this shelf. Always under the assumption that the 3 posts were the most effective and efficient way to stack...
Are your posts needing replaced/ground.. remembering an article by Mark..
How are all these comments tracking in your brain Mike?



I loaded it myself, the only reason I recently loaded it was because the first and much older shelf fractured. That shelf had been the floor shelf since 2013. It was only removed to replace the elements and vacuum the kiln. 


I suppose the stresses building up over time would explain the first fracture, but what about the second? It happened on the first fire.


There was no signs of warpage when I loaded it, and I did check to see if there was a wobble, and there was none. Now, our posts have some miles on them, and they have been dropped and knocked around. So, it is entirely possible we had a post that was no perfectly level. Plus we had some pots blow from too much moisture a few days ago, so there could have been some debris that wasn't completely cleaned out from the kiln. I did find some bisque shards, but nothing under the spacers, when I cleaned out the shelf.


It's possible the posts need to be replaced. I'll do that as precaution, and check them over to see if they need to be ground. Good suggestion...


This good stuff, I'm learning a lot...  No one ever told me how post the spacers when setting up a kiln. If I can get by with just 3 that would be nice.