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Filling The Kiln With Tiles


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Having posed the question on the Tumble Stacking thread http://community.ceramicartsdaily.org/topic/1993-tumble-stacking-the-bisque-electrics/page-3, I thought I'd start a new thread...

 

This is the top shelf loaded and ready to fire.  There are 49 four inch by 16mm terracotta tiles on the top shelf and 39 on the bottom shelf.

 

Recommended firing temp for bisque is 1020-1040C.  They will not be glazed, and will be installed inside.

 

It seems to me that there are too many in there, with not enough space.  

 

gallery_59202_986_27707.jpggallery_59202_986_1494.jpg

 

Will they fire OK, or should I spread them out do this in two firings?  I've never fired tiles before, and although I believe that tumble-stacking works, all the pictures/evidence I've seen so far shows varied shapes, not all tiles.

 

 

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I have that kiln, recognise the kiln brick popcorn :D Does your lid have many fracture lines? Mine seems to be getting loads. Sorry for going off topic.

 

They look a little tight but you might get away with it, I would think a .5cm gap between them would be good even if they were touching at the top. I'm thinking stack them like a card tower but maybe only one level. 

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The mass of the tiles doesn't worry me too much. Just go a little slower at the top end and the heat will penetrate through. Assuming your kiln has the power to get to cone 6, it should be able to fire a heavy load of tiles to low fire temps. What I don't like is the kiln furniture and tiles being right up against the walls. It's not good for the elements or the tiles to have them right up close like that- it can cause hot spots and burnouts in the elements, and hot spots on your work. Always stay an inch away from the walls.

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I've re-arranged them, but can't avoid the walls..... it's just tooooo small..    :angry:  I could get a third shelf in, but it would touch the lid.  It's far too hot in there to have another play, and although I'm now allowed to use my arm, it's started to ache, so that will have to be tomorrow's project.....

 

gallery_59202_986_47210.jpg

gallery_59202_986_47099.jpg

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Well done!

Hot in England???

Mark the calendar

 

About as hot as it gets, but variable.  It's like the weather gods have a manual kiln controller.  Hot today, cold yesterday, rain/hail tomorrow.  Oohh what fun it must be.  If there is re-incarnation, I want to be in charge of the weather next time around.

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Both firings successful.  So happy, thanks to all for your advice and suggestions.  Next step in this project is to cut a die and extrude those border tiles, then stamp 100 names.......That's going to be really (yawn) exciting (yawn).  Then another game of tetrominoes to load the kiln.

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  • 1 year later...

Hi everybody!

Thank you for this conversation I've been looking for it :)

I'm trying to fire 130 terracotta tiles and they keep blowing up!

I'm using 25% chamott terracotta material for a 1080 temp fire, the tiles are drying it for 3 weeks before the kiln...  and i think I'm not organizing it properly...

please give me tips for the arrangement if you have any, and for the kiln rate if it makes a difference...

Thank you so much for saving me in advance!!!

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Three weeks should be more than enough, unless the tiles are really big, or you live in a very humid climate.  

 

More specifics will help others suggest possible solutions.

 

How big are the tiles?

 

You are firing to 1080, I'm guessing that is Celsius?

 

What kind of kiln and kiln controller are you using?

 

Are you doing any type of Candling?

 

How exactly are you arranging the tiles?

 

For my classroom kiln, I do a relatively slow firing, to make sure those student projects (Of questionable construction) survive.  My program is 50 degrees F until 200 F.  Hold for four hours.  Then up to 900 F and hold for an hour.  Finally up to Cone 04.  With this program, I've had very few issues.  

 

I've never made tiles (Other than glaze test tiles), but I've fired plenty of slab constructed items, boxes, relief sculptures, etc.  I have had issues with some of them cracking or exploding, which I have solved by firing boxes upside down, or on stilts.  I've fired really large slabs on coils to avoid stress build up during expansion and contraction.  Some use a layer of sand for the same reason.

 

Best of luck!

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My firing was successful.  

 

Cheap terracotta clay was rolled out to 16mm thickness on a hand operated mangle/wringer.  

 

Cut with a commercial tile cutter.

 

 Allowed to dry to leather-hard, then carved by scouts.

 

Allowed to dry very slowly for four weeks before firing.

 

Not familiar with your clay, but I've never had any clay blow up.  How thick are you making them?  How well wedged is the clay?  How long are you drying them for. 

 

The cause for blow-ups is moisture.  If the tiles have air bubbles, the inside surface of the bubble will take forever to dry as it is not exposed to the air, and cannot evaporate from the surface, only through the bulk of the clay.  The outside surface forms a crust (during the drying/shrinking process) making it hard for the moisture deep within to evaporate out.

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  • 3 weeks later...

 Hi and thanks guys!

So time has passed but still no success...
My tiles are 40cm by 26 cm, 0.9 mm thick... BIG!
They are terracotta, not glazed and it's drying carefully then put in the kiln for 1050 (though I'm considering burning only to 950 (celsius) because i can't seem to succeed...)
how can i add a pic to this forum? i would like to show you guys my arrangement...
because they are big i'm putting them (on the 40 cm side) and stacking them like books on a book shelf, only with bisque spacers between them (from my formar broken attempts...)
i'm getting a small fractureon in each tile- on the side that touched the shelf, so i thought about using bisque powder (i dont know how to pronounce in english...)
what do you think is best? bisque powder or broken bisque tiles parts?
My kiln is old :( i dont know what to say about it... it's control pannel is very  wierd- it lets you decide the final temperature, the rate you're going up, and a  soaking time limit at the final temp...
 
thank's to all the answering angels in advance :)
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Dror:

I do not think your problem is with stacking,or drying, or with forming technique. I think your problem lies in your firing schedule; I think you are blowing through the inversion temp too fast. On the edges of the tile in direct contact with the shelf, I would expect to see small stress cracks.

 

From 1000f to 1100f, you should not ramp any faster than 100f (60c) an hour. I fire tiles up to 24 x 28 inches.

Inversion temperature is 573 celesius.

Nerd

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dror.  that old kiln does not have a "control panel".  somewhere on the orange part there will be a metal plate with info on it.  can you get a picture of it with all the info you see?   the clean interior with element protection and the color suggests it is an L&L.  more info will get you more answers.

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thanks @glazenerd,

what you are saying is very impressive! i also tried using another kiln with a smart control, but got the same risult- one middel crake on the side that touches the shelf.

I did pay extra attentions to that part-

2 hours up to 100 Celsius (212 Fahrenheit) staying there for 2 more hours for good dry. then 5 hours to go from 100-500C (212-932 F) and 3 more hours to 650C (1202F), then 5 more hours up to 1050C (1992F)...

I would like to ask how thick are your tiles? and what kind of material do you use? how many bisque powder in it? 25%? 40%? and what size 0.5, 1mm...?

and what do you mean in "Inversion temperature" when you say it's 573 Celsius. you probably mean the temperature where molecular water disappear...(?)

THANK YOU !!!

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