Introduction: Make a Ceramic Sphericon

Picture of Make a Ceramic Sphericon

A sphericon is a really cool shape, fun to hold, roll, or just look at.

You can find find more information on the sphericon shape from Paul J. Roberts

This instructable is designed for folks with some handbuilding experience in ceramics. If you have some pottery skills but are new to handbuilding, try to practice some of the basic skills of slab work before attempting to build your own sphericon. There is a listmania of recommended books for handbuilders on here

Some new photos added, including a view of the bisqued piece made in the course of this instructable. Hey, and now we have a picture of the final item after firing to cone 10 in gas reduction! I wiped most of the glaze off before it went in the kiln.

Step 1: Roll Out a Slab of Clay

Picture of Roll Out a Slab of Clay

Using your favorite tool (hands, large dowel, rolling pin, slab roller) roll out a slab of clay. The slab used in the example is about 1/4 inch thick. Aim for a consistent thickness.

Ideal thickness is influenced by the clay you're using and the size of the sphericon you are building. A larger shape requires a thicker clay slab. You can go much thinner with porcelain than with stoneware.

I'm using the house clay for this model, which is a high fire (cone 10) grogged stoneware.

Step 2: Mark Out Two Circles of the Same Size

Picture of Mark Out Two Circles of the Same Size

Use a compass or trace something to mark your circles on the clay slab.

KEY: make sure you have the center point of each circle marked.

You only need about 3/4 of each circle, so it's OK if you include some thin spots or other defects. Just avoid these parts in the next step.

Step 3: Cut Out 4 Identical Wedges (127 Degrees Each)

Picture of Cut Out 4 Identical Wedges (127 Degrees Each)

You can get a paper template of the angles from here and here

Simply match the point of the paper wedge with the center of your circle, and extend the sides as long as you need them to so it will fit.

Why 127 degrees? Well, it's 90 degrees * the square root of two. Geometry.

Step 4: Bevel the Curved Sides to 45 Degrees

Picture of Bevel the Curved Sides to 45 Degrees

Bevel the curved edge only to 45 degrees. This is best done with one of the many nifty tools you can buy from ceramic suppliers.

I'm using a homemade tool -- maybe I'll get around to building an instructable on that someday. There are a couple of close up photos below of my homemade tool. Briefly, it's constructed of two pieces of aluminum holding a wire at the desired angle. The flat bottom of the tool rides on the work surface. The flat side rides along the precut slab of clay. The wire is extended out to slice into the clay edge at the proper angle.

Step 5: Measure the Straight Side of Your Piece

Picture of Measure the Straight Side of Your Piece

TIP: this is the radius of your original circle. Include the bevel in your measurement.

Step 6: Draw a Square With Each Side = Straight Side Length

Picture of Draw a Square With Each Side = Straight Side Length

One piece of the sphericon should fit perfectly onto two sides of the square.

Use scratch paper -- this is an excellent way to recycle unneeded phone books. A permanent marker won't leave unsightly ink on your wet clay. Any running ink will burn off, but I like things neat.

TIP: it is worthwhile to use a proper right angle to make your corners here -- it will improve the ease of matching up the pieces in the final steps. (Hint: you can use the corner of your scratch paper for this too.)

REPEAT to make a second square!

Step 7: Bend Each Piece to Form a 90 Degree Angle at the Point

Picture of Bend Each Piece to Form a 90 Degree Angle at the Point

You may need to pinch the tip carefully, depending on your slab thickness. The goal is to gently curve the piece, resulting in the straight sides creating a right angle.

Step 8: Score Curved Edge of One Piece

Picture of Score Curved Edge of One Piece

Score the curved edge on one piece, then put it down on the square you drew, aligning the straight sides on the clay piece with the drawn lines. We're just scoring this piece.

Step 9: Score and Apply Slip to Curved Edge of Second Piece

Picture of Score and Apply Slip to Curved Edge of Second Piece

Apply slip to the second piece of the sphericon, after you score it.

Step 10: Carefully Match Curved Edges, Aligning Straight Sides With the Square Template You Drew Previously

Picture of Carefully Match Curved Edges, Aligning Straight Sides With the Square Template You Drew Previously

Use the handy square that you drew in step 6 to align the straight sides properly. You may need to nudge the curved edges a bit to get them to line up nicely.

If you used plenty of slip, some should squeeze out. This is good!

When building a small sphericon, say 3" in diameter or less, you can get away with matching up the pieces in hand, rather than using the paper square for alignment.

Step 11: Repeat With Remaining Two Pieces

Picture of Repeat With Remaining Two Pieces

Now is a good time to take a break, and let the pieces firm up a bit. For large shapes and/or thin slabs, it's particularly helpful to let it get cheesehard or near leatherhard before continuing.

You may try gently paddling just the curved seam to strengthen it.

Step 12: Prepare the Squares Formed by the Straight Sides for Joining

Picture of Prepare the Squares Formed by the Straight Sides for Joining

Score one square's edges and put it down. Score and apply slip to the second square's edges.

Do you want your sphericon to rattle? Wrap a small ball of clay in some scrap paper before you mate the halves together.

Step 13: Mate the Two Squares, Offsetting the Corners Where the Curves Meet

Picture of Mate the Two Squares, Offsetting the Corners Where the Curves Meet

This is the trickiest step. Fidget with it and you will get it to work. Align the pieces the way you want them. Make sure your seams are sealed. Try some paddling to refine the shape.

Here's one way to think about aligning the pieces properly. Hold the scored & slipped half in one hand. Hold the scored half in your other hand. Line up the corners with the curved seams without touching the two parts together. Then twist one piece by one quarter turn, so that the curves no longer align.

There's a nice 3-d image here}

Step 14: Finish Your Piece

Picture of Finish Your Piece

Add some texture if you want, and don't forget to make one small air hole and add your mark.

If you don't make the one air hole, your piece will begin to bulge out as the clay dries and shrinks, and may eventually crack.

Let it dry carefully, and glaze/fire according to your taste and the type of clay you used. If you do choose to glaze your piece, be aware that it could roll in the kiln. It is a good idea to use some little shims of soft firebrick to stabilize it. Or, woodfire and let the ash take over -- the wadding will hold it safely.

Why make this? It is not functional, just fun. Although, you could use it for a math lesson perhaps.

I hope you enjoy it. Please share your results! Post pictures in the comments and send a link to me on flickr if you're a member there too.


bptakoma (author)2013-06-12

I love your collection! They have a lovely mystical quality all together like that. You might want to keep them in a dish as someone slamming the door or a small earthquake could make them roll off the table. Hey, have you tried rolling one on the carpet? It makes a neat wobbly path .

Thanks for taking the time to share your pics. I really love seeing them.

Smalfrii (author)2013-06-11

Hey bptakoma, finally got around to posting the pictures of them glazed. The two bigger ones are 2.5 inches in radius and the smallest is 3/4 inch. Hope you like them :)

Smalfrii (author)2013-05-10

These are so fun to make! I've made four so far, all under 4". Wish I could make some bigger ones, but seeing as the school year is nearly out, we're out of clay to mix.

bptakoma (author)Smalfrii2013-05-10

Awesome! Please post a picture of them after they're fired too. Thanks for sharing the picture. I love it!

david the mudslinger (author)2009-06-14

beautiful glaze ( i love reduction!)
check out my ceramic concentric bowl tutorial if you get a chance.
thanks for sharing ideas

David the mud slinger

Thelonelysandwitch (author)2009-04-08

These are cool, what would be even cooler is this shape in ice cubes.

My claim to fame is I actually went to School with the inventor of the Sphericon. He bought the shape into School to show and everybody who saw it was impressed. He's a complete maths junkie and his handwriting was illegible! He was working on patenting the shape and selling the rights to a toy maker (Mattel?) AFAIK this fell through because although the shape is interesting, it's nothing more than a novelty/conversational piece.

bptakoma (author)hot-fresh-rider2009-04-16

Wow! well, at your next reunion, please tell him how much we've been enjoying his shape. The math geeks love it. The pure crafters love it. We're all happy with it being strictly interesting. I will note that there is a wide segment of potters that focus on functional ware. They are less enthusiastic about something that's just a cool shape.

or a sphericon superball!

this guy made one from lucite.


bowmaster (author)2009-04-08

This looks really cool. If only I had the skill to make one. What's the smallest and largest one you've made?

bptakoma (author)bowmaster2009-04-08

Hey thanks! The smallest so far has about a 1.5 inch radius. The largest was just under 10 inches in diameter -- I planned it that way as the kiln fee where I fire pottery is significantly higher for pieces over 10 inches in any measurement. I've been thinking that the shape is so appealing, it would be great to make earrings and a pendant out of precious metal clay (pmc). I'll make sure to share pics if I ever get around to that.

bowmaster (author)bptakoma2009-04-08

For jewelery you could make the size you want then make a mold and cast it in bronze or other metal and polish it so it shines.

bptakoma (author)bowmaster2009-04-09

The pmc people make a clay that fires to bronze now. See here. With the metal clays, it's easier to make a hollow piece. Although, I can also appreciate that a solid piece would have an appealing heft. Not sure if I would want that hanging from my ears. Ooh, but as a bauble to play with on a key chain maybe...

bowmaster (author)bptakoma2009-04-09

I was think more along the lines of a mold but the clay is cool.

discontinuuity (author)2009-04-08

Very cool! I've done some handbuilt vases before, but I've never heard of a sphericon. I think I saw one of these being made out of chocolate on the Food channel once. Is wood-firing something that you can do in your backyard, or do you need special equipment? I don't have access to a kiln, so I haven't made any pottery since high school.

bptakoma (author)discontinuuity2009-04-08


Woodfiring is done in a kiln -- not something you'll be able to set up for a backyard experiment. There is something called pit firing that you could try. See this link I've never tried it, so I can't guide you too much there. You can always check into the local community and art centers. Even a paint-your-own-pottery place will probably fire things for you, for a small fee.

You could still make the shape in other materials. There are the paper patterns in step 3 -- so you can always make it in paper. Or polymer clay that bakes in the oven, or paper mache, or maybe metal mesh and concrete! Wouldn't that be cool.

justanassembler (author)bptakoma2009-04-09

pit firing is fun, but it is obviously nowhere near as hot as a typical wood-firing... Woodfired kilns are generally fired to at least cone 10 (on the orton pyrometric cone scale) which is around ~2350 F, a lot of people who wood fire actually go higher than this as it changes the effects of flame marking, fly ash distribution and melt, among other things. The temperature to which you fire is dependent on a lot of things, but part of what you want to tailor it to is the range of your clay body (you don't want to fire a cone 6 clay to cone 10, you'll be disappointed and frustrated to find a pool rather than the object you initially put in the kiln...) and you also want to make sure that you are properly vitrifying the clay body in order to maximize durability and non-porosity.... Getting back to pit firing--I believe temps in a typical pit-firing top out around the 1600-1700 degree (F) range--surely people have and do fire slightly hotter, but its not typical. If you want to see some more information on wood firing check out the following sites:

FeedTheGrid (author)2009-04-08

Sphericon's rock! How cool; thanks for sharing, bp. Art will save the world!

Sunbanks (author)2009-04-08

These are really cool looking :D I might make one of these in ceramics class.

mysticstranger (author)2009-04-08

i haven't done ceramic work since my senior year of hs but i miss it this reminds me a lot of when we were doing darts and almond cuts very nice

gmjhowe (author)2009-04-08

Excellently written instructable. I found it easy to follow even though i have never done any ceramic work. Maybe you could provide a quick description of how you made your 45 degree angle cutter? (just enough for those of us who can to work it out)

bptakoma (author)gmjhowe2009-04-08

Thank you!

I took some pictures of my tool and the one that inspired it. You can see them on flickr

1/2 inch square aluminum rod from hardware store, aluminum bar about 1/8 inch thick from same, pop rivets, 1/4 inch thumb screw, 1/4 inch nuts & lock washer, about 20 gauge hardened steel wire

tools used: scroll saw to cut metal to length and cut channel where wire goes underneath
dremel to smooth edges and cut slots in upper piece for wire
drill for 1/4 inch hole for thumb screw and 1/8 inch holes for pop rivets
pop rivet tool

bptakoma (author)bptakoma2009-04-08

here are some pictures showing more of the details of my bevel tool for clay (and that I'm not a good one for keeping tools meticulously clean).

Kiteman (author)bptakoma2009-04-08

You ought to edit your instructable and add these photos to the appropriate step.

bptakoma (author)Kiteman2009-04-08

excellent feedback. Done! Thank you for the suggestions.

gmjhowe (author)bptakoma2009-04-08

Ah you see, i know understand its made using a piece of wire to cut. I agree with Kiteman, though, i reckon you should add those pictures, and that description (along with the link) as an extra step, for people to follow.

SinAmos (author)2009-04-08

So, wait, I make this shape and then when the aliens land, I can put into their G-drive input console and take off in their ship? That's what you're selling me, right?

golddigger1559 (author)SinAmos2009-04-08

no man the g- drive doesnt exist your thinking of the cockpit

munchman (author)golddigger15592009-04-08

But otherwise, yes

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