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missholly

Hints On Firing Large Tiles?

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im making alot of mosaics. i dont really like the look of grout, so im not grouting them. just putting them back together and attaching the pieces to a board.

 

what would happen if i tried to fire the whole thing in one piece? do i have to worry about warping or cracking?

im talking items around 15 x 9 inches. 3/8 inch thick.

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Are you making the tiles or are you buying them? What cone range are you firing to? Do you have tile racks? ... I will asume that you are using store bought tiles which are usually low fire uaing a small electric kiln. You should be fine firing then flat on a shelf but I would a slow heat rise and a slow down fire. Try to keep the down fire to about 200 degrees an hour till about 600 to 800 degrees with the pluges in. dont open the kiln until its below 300 degrees.

 

 

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im making them.

 

basically carving a picture out of a slab.

 

im bisquing to 05 and glazing to 6. i do have tile racks but have only been using them for glazing bisqued tiles. (i figured greenware would warp)

 

i do a slow rise (at least i think its slow) although i actually dont know the temperatures im working with.

my kiln has 5 switches and im doing one every 1/2 hour as per my teacher.

 

how do you do a slow down fire?

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I fire slabs that are bigger than that...some are 24 , 25 inches by 20 inches or so. I dry them slowly on sheetrock with a piece of newsprint between them. I apply knobs for hanging on the back so they are not sandwiched between sheetrock. I also wax the edges about two inches in using liquid wax

to prevent the edges from drying too quickly and warping. I bisque fire these on edge leaning against bricks. I glaze them in rau also on edge. They are about 3/8 to 1/2 thick. At what temperature are you glazing? You can see some of these slabs on http://www.marciaselsor.com or

http://www.americanp...063108372215984

 

 

For carving mosaic patterns into a slab, 3/8" may be too thin.

 

Marcia Selsor

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I fire slabs that are bigger than that...some are 24 , 25 inches by 20 inches or so. I dry them slowly on sheetrock with a piece of newsprint between them. I apply knobs for hanging on the back so they are not sandwiched between sheetrock. I also wax the edges about two inches in using liquid wax

to prevent the edges from drying too quickly and warping. I bisque fire these on edge leaning against bricks. I glaze them in rake also on edge. They are about 3/8 to 1/2 thick. At what temperature are you glazing? You can see some of these slabs on http://www.marciaselsor.com or

http://www.americanp...063108372215984

 

 

For carving mosaic patterns into a slab, 3/8" may be too thin.

 

Marcia Selsor

 

 

That's a great idea, waxing the edges! I feel that the warping problem starts with the clay (I use Standard Ceramics 104), and slab prep- I use a Bailey dual drive roller; equal compression on top and bottom of slab. Dry between two pieces of sheetrock. Some of my tiles are 18" and 1/4 inch thick, and come out flat as that famous building at Times Square. . .

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beautiful work marcia!

boy, do i have some learning to do!

 

ive never thought of using sheetrock. this is for purpose of keeping the tiles flat, im assuming?

does it also draw out moisture from the clay?

 

whats the point of the newsprint?

 

this is the one im working on now. (the owl)

i mainly wanted to not cut out all the pieces to save me time and work.

they would all be going back together anyways.

 

the two tikis are glazed and ready to be fired.

 

photo7.jpg

photo2.jpg

photo1.jpg

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yes the sheetrock draws the moist. Be sure to tape the edges of the sheet rock to keep the gypsum out of your clay.

The newsprint keeps the clay from sticking to the sheetrock. I am going to ad a picture of the raku slabs in my forum gallery to show you the scale.

I have filled my quota for uploads on messages.

 

Nice work you posted. Very clean and precisely made. Reminds me of NW images.

Marcia

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im making alot of mosaics. i dont really like the look of grout, so im not grouting them. just putting them back together and attaching the pieces to a board.

 

what would happen if i tried to fire the whole thing in one piece? do i have to worry about warping or cracking?

im talking items around 15 x 9 inches. 3/8 inch thick.

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im making alot of mosaics. i dont really like the look of grout, so im not grouting them. just putting them back together and attaching the pieces to a board.

 

what would happen if i tried to fire the whole thing in one piece? do i have to worry about warping or cracking?

im talking items around 15 x 9 inches. 3/8 inch thick.

 

Missholly, try firing your slabs on end. support them on each side with a brick. i have found that firing on end really reduced the amount of warping and/or cracking

Stephani Stephenson

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I have found with all tiles, if i score the back of them lightly then they can move without warping.

if you look on store bought and industrial fired tiles their backs are not just flat.

its like giving tiles legs to stand on and allows heat and air to circulate better around the tile in firing

I hope this helps.

 

when you said 'fire the whole thing at once" What did you mean exactly?

 

I like to put sand underneath the tiles in the kiln.

I place them in the kiln the way they will be arranged together on the kiln shelf which is covered lightly in sand.

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Guest patrick198

Are you making the tiles or are you buying them? What cone range are you firing to? Do you have tile racks? ... I will asume that you are using store bought tiles which are usually low fire uaing a small electric kiln. You should be fine firing then flat on a shelf but I would a slow heat rise and a slow down fire. Try to keep the down fire to about 200 degrees an hour till about 600 to 800 degrees with the pluges in. dont open the kiln until its below 300 degrees.

 

 

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stephanie,

i never would have thought to do that. i would initally think that it would warp under its own weight. ill give it a try!

 

linnet,

that makes sense to me.

im basically carving into a slab and trying to fire the whole thing. instead of cutting each and every piece out and putting it back together.

 

whats the deal with the sand? is that just to raise it for circulation?

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The sand works like ball barrings and allows the work to move during firing reducing the stresses from shrinking that could cause cracking in large pieces. I like to use alumina for the same think. Higher melting temp, rounder shape

 

 

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