Commercial Clay: Review
Updated: May 9
I'm going to give a brief review for some commercial clay bodies that I have tried. These are my personal experiences and opinions, all products mentioned were either purchased by me or clay I have used in the studios I teach at. By the way, most moist delivered clays come stiff, so I usually remoisten before using (spray with water/cut into chunks and wrap in wet towels and store again in tupperware). In no particular order:
1. Brown Bear from Kentucky Mudworks
From the manufacturer:
"A nice super smooth, plastic body that fires a dark chocolate brown at cones 5-6. Matures cone 5-6. Won't bloat at soft cone 7 if fired slow through the last 300-400F. Contains no grog. Gives nice warmth to glazes, giving that reduction look to them in oxidation.
*Our tests with our Super clear glaze gave us little to no bubbles or green tint to the clear glaze.
Contains less than 2% Manganese.
Shrinkage 11% Abs at cone 6 0.2% "
My experience: This stoneware has a rubbery, slick-oil feel. This makes it very easy to clean, and easy to wedge if at the right moisture level. It is very very smooth, but not buttery like porcelain. When throwing, it is a medium brown color. The real rich darkness appears in the glaze fire.
Feels nice and tight, so it is easy to carve on. The smoothness allows for beautiful foot rings! Attachments seem to be fine, def need to slip and score. I liked it better for throwing than for hand building. When I bisque to ^06 the wares are way too absorbent for glazing. I chose to fire between ^05-^04 which was better, but I believe that my 8-hour firings were still too fast. It must have needed more time climbing to temperature to remove moisture and impurities. My biggest issue with this clay is its compatibility with glaze. Certain glazes seem to pinhole badly, crater, or have weird textures on this clay but not on my other clays. The other downside is certain glazes appear muddy or invisible on this clay, especially glazes that have been twice fired. I fired to cone 6. Super vitrified vibes got me like 😍 but glaze results got me like 😢
Bought this from The Ceramic Shop. $42.00 for 50lbs.
2. Iceman from Kentucky Mudworks
From the manufacturer:
"KyMudworks premium white clay body. A cool white stoneware that is the durable and a pleasure to throw. Does not get too soupy if you throw with a lot of water. Super plastic, throws and hand builds well. Matures cone 5-6. Can be pushed to cone 7 slow fired.
Shrinkage 11.5% Absorption at ^6 1.4%"
My experience: the better version of Standard's #551 VP Porcelain (really a b-mix, not real porcelain). The clay threw me off a bit because the color appears gray and a bit grainy, even though there was no grog. It fires like a buff off-white, more warm than it is cool. The Brown Bear clay felt easier to get thin walls, easy to manipulate. I really disliked this clay for throwing. Collapsed easily, despite its stiffness. It wobbles when thin, cannot support stretches well, and cannot collar well. Not very plastic, in fact, less plastic than the Standard 630 even though 630 has grog and comparatively larger particles. It felt sandy and grainy, with chunks coming off easily even if it was wedged well. There are cracks even when wedging. Thirstier than the Brown Bear when it came to throwing. It also did not move as smoothly with sponges (both the standard yellow and the xiem finer spongers) compared to other clays. Attachments are okay.
However, I liked it much better for hand building. I made a slab tray that warped a lot while it was in green stage, but it magically evened itself out in the final firing. I liked that for slab pots and coiling I was able to join pieces without much slip. Simply water was enough, especially if the clay is on the softer side. Looks great for coiling.
Settles a bit when reclaiming. One time I didn't use my immersion blender like I usually do and it was still good.
Bought this from The Ceramic Shop. $32.50 for 50lbs.
3. Troy Porcelain from Standard Ceramic Supply
From the manufacturer: #437 ^9-13
"A versatile, plastic English kaolin porcelain body. It throws and takes glazes well, and can be used in reduction, wood, and salt firings. Translucent when thin; wide range of color/texture in long wood firings."
My experience: I used this for a wood firing because I saw the beautiful bright flashing. It is very pretty to look at but a pain in the ass to use. I used it only on the wheel, so I've never tried hand building. At first it feels very soft and buttery, easy to wedge. Must use when it is soft enough that you can press your thumb into it, but not soft to the point where it is sticky. If it is stiff, forget about it. It will only dance and wiggle against applied force. Cannot get very high without torquing or collapsing. I know others who have used a torch or waited for the clay to set up, but I've only attempted to throw in one sitting. I found a way around that, and it was to throw multiple pieces then assemble them together later. Some redeeming qualities is that is very smooth, and very flexible in terms of stretching and collaring. It is forgivable in the sense that I can change the shape of something multiple times and it will easily adapt. I really enjoyed making closed forms and lids with this. It is extremely creamy, like sour cream, more so than other porcelains and really feels like a true grolleg creamy porcelain.
Took a while for me to get used to, and I even added molochite grog for some support. Don't use too much water. It gets very sticky and hard to wedge if it's too wet; must let it set up. Not the kind of body that can be "wedged until it's workable", it really does need time. Porcelain by nature is a delicate thing, so I've dealt with lots of broken things in both greenware and bisque. Trims well even when it's on the drier side of leather hard. Is not forgiving if you try to manipulate the vessel during leather hard stage... adding slip/water only helps a little. When I use stoneware, I let it dry under loose plastic. With this body, I let it dry open air and it dries nice and even.
For reclaiming, I notice that discarded trimmings and pieces that are not bone dry reclaim easily (other porcelains I've used needs it to dry thoroughly for it to reclaim fast). Then I use my immersion blender, then pour it on plaster.
Bought this from Bailey Pottery in 2019/2020 for $36.50 for 50 lbs. 70$ for 100lbs. BUT THAT SHIPPING DESTROYED MY SOUL :( ($60 for s&h, 12$ tax!)
4. #630 White Stoneware from Standard Ceramic Supply
From the manufacturer: "C/6
Contains fire clay and mullite which enhances thermal properties.
Cone 6 Shrinkage 13.0% Absorption 1.5%" My experience: Good for beginners. Gray when wet, still gray when fired. It has a stony, light warm-gray color with visible grog. This clay also has a bit of "weight" to it. Even when throwing thin, it's probably the heaviest of the white stonewares I've used. It has that sandy feel to it. It is fine for throwing, but in the drying and firing process I haven't been happy with it. I've seen it crack and bloat more than other clays. Attachments are fine but it needs to dry evenly. Pretty forgivable when manipulating shapes, for example, collaring in a big mouth. That's why it is easy to work with for beginners. Dries incredibly fast while wedging and when left out. So it is better to pick clay that is softer than you think you need, because by the time you sit down it has already started to stiffen! I enjoy using it for sturdy things, like a big planter or heavy pot. Takes glazes well.
$30 for 50lb from The Ceramic Shop.
5. #182 White Stoneware from Standard Ceramic Supply
From the manufacturer: "^6-10 Near white plastic stoneware body. Good for use with bright glazes. Available with and without fine grog. Cone 8 Shrinkage 11.0% Absorption 2.5% Cone 10 Shrinkage 12.0% Absorption 0.5%" My experience: great white stoneware. Fires a buff and rather warm cream color at cone 6 ox. but a light grey color in reduction. This is due to the red iron oxide content reducing to black iron oxide. Easy to throw, can get considerable height and size. Nice for large bowls. If the lip is too thin or you overwork it, it will warp for sure. The shrinkage has been a bit of an issue for me, especially for lids. When I am using porcelain the lids always fit pretty well, but for this clay it is trickier because it has been harder to gauge the shrinkage/warpage for mouth openings. The grog is fine mesh, so it's not too visible. It has a smooth, plastic feel to it, but needs continuous water to throw, more water than the #630. I also feel like it centers easier than the #630. Since it was made to vitrify at higher temperatures, at ^6 I do notice it absorbs quite a bit of water (for example, when doing the dishes).
UPDATE FOR A YEAR LATER: I do find that slime and mold can grow on the unglazed parts of this clay. Even handwashing pots can lead to a slimy feeling on the surface. I would NOT recommend producing unglazed food wares if you're firing to cone 6. Think about it, something meant to mature at cone 10 is no where near good enough at cone 6 for everyday use. Simply put, 2.5% absorption is a big deal. And you will see issues arise within a few years.
$29.50 for 50lbs from The Ceramic Shop.
Next blog post: reviewing clay bodies from the ceramic supplier Sio2.