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Porcelain And Stilts


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I read somewhere not to use stilts with porcelain (high fire) as the wire will meld into the body...but no instruction as to what to use instead (alumina sand??) What are some other ways to keep the glazed pieces off the shelf? 

 

Thanks in advance  <_<

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The only way I know is to not glaze the piece where it touches the shelf, and to use a good kiln wash to prevent plucking.

 

As far as I know, stilts are not useful with high fire ceramics.

 

If you look at high-fired pieces, even commercial stuff like Dansk, you'll see that the feet are never glazed.

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The only way I can think to have a glazed bottom of a high fire porcelain piece would be to do a second glaze firing with a low fire glaze on the bottom of the pots, then you could use stilts. I agree with leaving the pot unglazed on the bottom and using a good kiln wash.

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In High fire work the foot or bottom of pot is left bare with no glaze.

Mid range is the same deal as well.

Only in low fire are metal pointed stilts used.

You can use 3 point all ceramic points to higher temps than low fire but with porcelain the pots can warp as well.I have used them In the salt kiln once to cone 10 and they held the pots but were toast getting them off.

Mark

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Even unglazed porcelain will stick to the shelf in high firings ... Sometimes it's just one small area that sticks leaving a chip behind.

One way to help stop this is to add some alumina to your wax resist and coat any area that touches the shelf with it. I also use kiln wash on my shelves and make sure all areas are covered.

Some potters use a silica bed under each pot ... I am not in way a an expert on wood firing, but can anyone else say if you could just use the same mix of wadding that you use in wood firing?

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I make those small porcelain candle holders with trimmed feet. They used to always pluck until I started putting alumina hydrate in the wax resist. High fire pots do not have glazed bottoms. Iron melts at 2,000 degrees F. Stoneware is fired to 2380 degrees F.Stilts are useless at these temps.

TJR.

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I should have specified that I was talking about unglazed porcelain--as Chris notes--and the info I read said not to use silica on my shelves....so I guess just the kiln wash, and if that isn't sufficient, I'll try the alumina--thanks all!  

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I have seen porcelain fired in the range of 8-10 fully glazed using homemade stilts. These stilts were made out of kiln elements and were three little stumps of wire stuck into a base of clay.

 

I was surprised how well they actually worked. Maybe it was something to do with the glaze but it was quite easy to remove the stilts and sand down the ugly holes left.

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crystal glazers use a separate support sort of like a saucer with a tall center that matches the diameter of the foot of the glazed item.  the glaze always runs so it is caught in the saucer.  once cooled, the whole piece is whacked gently and the saucer drops off.  it was only held on by the glaze so once that is ground away, there is no evidence of how it was done.

 

look at the website for the Pottery Boys to see wonderful crystalline glazes.

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  • 3 months later...

Soft brick sounds like an awsome idea Marcia.

 

What ceramic material do they use for the custom made stilts, props, legs to keep the porcelain from sagging?

Is this a one use material or could it be used multiple times?

Would this be good material for glaze stilts?

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  • 1 year later...

I just saw mentioned using soft brick as a kiln stilt.... I have no idea what that is, but has me thinking fire brick... Could I use fire brick (coated in kiln wash) as little pads to set fully glazed, slab Christmas ornaments on to fire? Any other ideas?

Soft brick is Insulated Fire Brick. Soft enough you can cut with a miter saw to make thin slabs. A coat of kiln wash on top would work fine.

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I just saw mentioned using soft brick as a kiln stilt.... I have no idea what that is, but has me thinking fire brick... Could I use fire brick (coated in kiln wash) as little pads to set fully glazed, slab Christmas ornaments on to fire? Any other ideas?

 

 

Wasn't sure if you meant "fully glazed" to mean they are glazed on the front and back? If the ornaments are fully glazed they will stick to the kiln wash on the fire/soft brick.

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since i just spent some time pounding kiln shelves lined with kiln wash to remove glaze stuck in between i agree with min. you will have to grind the kiln wash off. lot of work. 

 

wonder if you can try a physics test. balance it on a built in point that you can break off and grind down. 

 

hmmm. myself ^5/^6 have used stilts on glazed stoneware and it worked fine. i know you are not firing beyond ^6. now i have to try with porcelain when next semester starts. 

 

why should the clay body matter though? its about glaze and wire right? at school i've done 2200 (^6 body and glaze) with stilts and the stilts just popped off. this is the kind of stilts we used. dont know exactly what brand it was. but there was low fire stilts as well as 'high fire' stilts. the quality of the wire was different for sure. http://www.unitednow.com/product/6176/amaco-pointed-stilts.aspx?item=10049&gclid=CPm-9cmS5tACFUtNfgodjMsByQ

 

does glaze sit differently on stoneware as opposed to porcelain? 

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