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substitute for sand on kiln shelf?


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#1 Ginny C

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Posted 17 April 2013 - 09:42 AM

I'm loading a bisque load right now and one large slab-built dish should probably be placed on sand to allow it to slide when expanding and contracting. (Or so I've read somewhere...)
I don't have any sand! Can I substitute a bit of kiln shelf wash, dry? Or will that fly around and cause problems?

I'm hoping for an immediate reply!! Posted Image

Ginny Clark

#2 potterbeth

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Posted 17 April 2013 - 10:23 AM

You could use a little fine grog. If you use sand, it should be silica sand...not the garden variety. A little dry kiln wash might be OK. A little alumina hydrate would be better. Doubtful it would fly around, just be cautious unloading so you don't dump it in your kiln.

Probably goes without saying, but use your flattest kiln shelf. If you're using a top loading kiln and you're able to handle the weight, load the piece onto the shelf before putting it in the kiln. Think about positioning the shelf for the kiln posts as you lower it in.

#3 TypicalGirl

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Posted 17 April 2013 - 02:57 PM

I worry about sand/silica getting onto my other pieces, so I use "wads" of kiln shelf paper.
Cathi Newlin, Angels Camp, Ca
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http://www.CNewlin.com

#4 Ginny C

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Posted 17 April 2013 - 05:03 PM

I've never used kiln shelf paper, but now I know what it is. 3 questions:
Do you make wads of it because using it flat would still not allow a dish to slide on it?


With wads, isn't there a chance that the bottom will sag where it is not supported?


And finally, are the wads re-useable?

Thanks!
After calling Amaco, I used kiln shelf wash dry under the big dish.
I bought "play sand" very cheaply at a building and garden supply store, but not knowing if it was really silica sand and seeing that it was wet, I decided to try the kiln wash first. I'll report tomorrow how well it worked.

Ginny




#5 Nelly

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Posted 17 April 2013 - 05:12 PM

I've never used kiln shelf paper, but now I know what it is. 3 questions:
Do you make wads of it because using it flat would still not allow a dish to slide on it?


With wads, isn't there a chance that the bottom will sag where it is not supported?


And finally, are the wads re-useable?

Thanks!
After calling Amaco, I used kiln shelf wash dry under the big dish.
I bought "play sand" very cheaply at a building and garden supply store, but not knowing if it was really silica sand and seeing that it was wet, I decided to try the kiln wash first. I'll report tomorrow how well it worked.

Ginny




Dear All,

Is play sand okay?? I have two bags left over from a patio installation project last year. I would love to be able to use it instead of the sand purchased from my supplier. Is it okay to use this under say platters.

Nelly

#6 potterbeth

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Posted 18 April 2013 - 10:59 AM

Put a little of the sand in a small test pot with sides and include in your next glaze firing. If there's any funkiness, the pot should contain it to save your shelves, other work, etc.

#7 perkolator

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Posted 18 April 2013 - 12:37 PM

when I load large flat objects (like expansive slab forms or big plates/platters) I like to load them on top of balls of kiln wadding as opposed to grog/sand. haven't really had any issues this way. make sure you make lots of little balls around size of large grapes (I guess it depends on how large/heavy the piece is), then place them under the piece in a grid pattern about 3-4" apart so the piece is fully supported underneath. a substitute to kiln wadding could be some clay balls rolled in silica or alumina. my kiln wadding recipe is equal parts grog, silica, kaolin made into clay consistency.

#8 Ginny C

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Posted 18 April 2013 - 02:26 PM

The kiln wash worked...or at least the dish did not warp. I'll post a photo.
I appreciate all the suggestions. I've had a problem in the past with the feet of a dish pushing up just enough to show through after firing, so I thought putting this one on something would do the same thing. Perhaps my earlier pieces were just too thin. This one is certainly thicker.
Now to see if the glaze ruins it!
ginny
(enlalrge the photo to see the pattern, from an old doily and a nylon lemon bag.)

Attached File  photo 1.JPG   94.91KB   63 downloads

#9 neilestrick

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Posted 18 April 2013 - 02:53 PM

Feet pushing up, or technically the pot sagging down over the feet, would be due to the piece being too thin. That probably wouldn't happen until the glaze firing, though. In bisque, the clay does not soften up. Either make the pot thicker, or add more feet.
Neil Estrick
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Owner, Neil Estrick Gallery, LLC
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#10 KathyG

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Posted 19 April 2013 - 12:40 PM

I just glaze fired two large platters and used a generous coating of lid wax (wax resist + alumina hydrate) on the bottoms. They did great, but left lots of dust to clean up. No dust got in the wrong place during the firing. Posted Image

Kathy

#11 TypicalGirl

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Posted 19 April 2013 - 02:18 PM

Hey Ginny,
I used the term "wads" rather loosely.
I really meant that I use pieces of kiln paper under the feet of flat pieces, or sculptures if I'm afraid they might move around.
The paper becomes brittle after the first firing, but with care, it can be reused.
If you email me your address (through my website), I'll send you a bit to play with.
I do sell it in my etsy shop, but I'm happy to send you a piece to see if it will work for you ;-)
Cathi Newlin, Angels Camp, Ca
box49@caltel.com
http://www.CNewlin.com




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