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Reccomendations For Sc White Stoneware/porcelain


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I have been considering a return to a white clay body with Standard Ceramics, ^6 range. I believe the last time I used a white body was with either the 240, or the buff/off white 553.  I was wondering as there are lots of folks out there using SC clays. . . what do you like/recommend. Remember that I can throw, and a challenging, but rewarding clay would not be a problem for me. . . . I think!  I usually split my order with two different clay bodies, a light and darker. This time with a light to medium and a white/off white.

 

Best,

Pres

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I have been considering a return to a white clay body with Standard Ceramics, ^6 range.

 

I fire manually, and make certain the ^6 cone tip touches the kiln shelf. ^7 is usually at 35 to 40 degrees off.

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It's been many years since I threw anything but porcelain, but I still remember Standard's 181 white stoneware very fondly.  It was a pleasure to throw, strong and plastic.  However, though it is listed as 6-10, I fired at 8, with excellent results.  It's possible it would be a little underfired at 6.

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Their new one, 630, is nice, but I think some glazes don't fit as well as they do on the 240, etc. I've had some crazing, but I'm not sure if it's the clay, the firing, or the glaze. Doing some testing on a mixed white batch (mostly 563, with a bit of the 240 and 630 that was leftover).

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We use a lot of 240 in my studio, but it is very fine grained, so not all that forgiving. We also use a lot of 630, which is very forgiving and a pleasure to work with whether throwing or hand building. It's a little more grey-white, where as the 240 is yellow-white. The 630 is basically a cone 6 version of 182. It has fire clay in it, so it has a little more tooth, although it feels quite smooth when working with it. I use 365 grolleg porcelain for most of my work, which is one of the best throwing porcelains I've ever used. It's not quite as glassy as some other porcelains, but I almost never have warpage or cracking problems. I've made 50 pound planters with it with no problems. 181 is a cone 10 body, very smooth, prone to cracking and not good for larger pots. We also use 112 in my studio, which is their speckled brown. It's an excellent stoneware body, one of my favorites of all time. They also make a non-speckled version, 225.

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Thank you Neil.

If I remember correctly. . . yeah memory. ... I think I used the 240 in the 90's while I was using the 112. I like having two different body colors. I could throw pretty well, and tight with the 240. but had to alter my firing schedule as the 240 would get spiral spring like cracks in bisque that the 112 pots would not. Yes it was slightly yellow in color. I have considered going back to it, but your mention of the 630 is interesting as I was looking at that also. My concern is using glazes that work well on both of these bodies, the 112 and the 630. Do these work for you without glaze adjustment?

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Thank you Neil.

If I remember correctly. . . yeah memory. ... I think I used the 240 in the 90's while I was using the 112. I like having two different body colors. I could throw pretty well, and tight with the 240. but had to alter my firing schedule as the 240 would get spiral spring like cracks in bisque that the 112 pots would not. Yes it was slightly yellow in color. I have considered going back to it, but your mention of the 630 is interesting as I was looking at that also. My concern is using glazes that work well on both of these bodies, the 112 and the 630. Do these work for you without glaze adjustment

 

The 240 came out just a few of years ago. You're probably thinking of the 181.  I have no glaze problems with the 112 and 630 for the most part. With so many clay bodies and so many glazes being used in the studio it's impossible for all of them to work on all of the bodies, but the 112 and 630 seem to work well with most of them. My iron red looks amazing on the 112!

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Good to know about the iron red, as I have been considering addition of an iron red to the glazes I use. My only hesitation, is that I have not used it in combination with other glazes as it seems to pretty much "take over".

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We have been using 240 and 112 in the teaching studio with commercial glazes (purchased powdered) in 5 gallon pails for about 5 years, firing in a vented electric kiln to cone 5 tip touching. This cone suits the glazes we use, many of which will begin to overfire at cone 6. We have not tried the 630 clay body.

 

At cone 5, none of the Standard white bodies (aside from 630 which I have not tried) are truly mature. If the glaze is not tightly sealed, the clay body can absorb enough water to ruin your grandmother's antique dining table. We have run into a couple of glazes recommended at cone 5 which did not prevent seepage. I struggle with even using the clay in the studio, but our adult students love the feel and the fired results, so we march on. (Until very recently, Standard was our only easily available clay so we had little choice. Now, all the test tiles are made!) At cone 6, you will likely find more reliable results, but beware uneven kiln temperatures. I have also tried all of the white Standard bodies which include cone 6 ranging up to cone 10, none of which were remotely satisfactory at cone 5-6. A Standard tech once told me that my personal standard for clay body maturity seemed to run around 4% absorption or less, but the industry standard for stoneware begins at a higher absorption rate.

 

The 240 is less forgiving re: warping and cracking, especially if it's too thick, if there is large variation in wall thickness within the pot, or if it has not been well compressed, but you have the experience to deal with that. Surprisingly, children's work is LESS likely to have problems than adult's work, probably because they're working smaller and getting more one-on-one tutelage plus the benefit of the instructor determining how their work dries, etc. The 240 provides an excellent background for commercial underglazes. As an aside, the speckles in the 112 do show through many commercial underglazes. Also, the two bodies are similar in shrinkage/absorption and recent experimental agateware shows promising results, but the jury is still out!

 

Re: using the same glazes on the 240 and the 112, all of our glazes will work on both although some are more aesthetically pleasing on one body. Consistently, glazes are MORE prone to running on the 240, especially in layering glazes or thicker applications. I have found this to be the case on all mid-range white clay bodies. Going back to the clay body maturity issue, the glazes that allowed water seepage on the 240 did not have any problems on the 112. Anticipating the question...yes, glazes, especially transparent ones, are more likely to craze on the 240.

 

Finally, recycling 240 and 112 scrap together results in a lovely light tan body with speckles that is great to use. Glazes results are very similar to those on 112.

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I have used standard's English Porcelain 365 - which fires to a ^6 - quite white and strong -- absorption should be less than 1% at ^6 - I have thrown with it and hand built but only about 50 lbs - so no extensive experience with it.

I have not had any glazes fail on it. 

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  • 4 months later...

Checked back on my records, and found that the white, off white clay I was using was the 553 Warm Buff clay. I am going to order clay this next week and have decided on either the 112, or the 225. Maybe going towards 225 because of concerns for throwing some newer forms including mortar and pestles. I don't think the manganese would be a good thing in the herbs. :blink: . At he same time I am still pondering using the 553 again, or going to something like the 630. As I am concerned about being able to do chalices with these clays, Porcelain may not be a good choice so I am staying away from that.

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