Robert Serb's Ceramics Notes

These are comments and thoughts I've had about the pieces I've made over the past 7 years, and about pottery in general. To see the gallery of pieces I've made, Go Here or click on "Ceramics Pieces" on the left.

NEW FOR APRIL 2009

I've revamped this site a bit, and broken it into four sections: current goals and projects, a basic pottery tutorial, a more advanced tips and tricks section and a bunch of notes and thoughts on specific pieces and techniques.

      So what were you interested in seeing?

• MY CURRENT GOALS AND PROJECTS?
• MY BASIC CERAMICS AND POTTERY TUTORIAL?
• MY ADVANCED TIPS AND TRICKS SECTION? or
• NOTES AND THOUGHTS ON PIECES I'VE MADE AND TECHNIQUES I'VE TRIED?

MY CURRENT GOALS, PLANS, AND POTTERY PROJECTS

A jar with a knotted Celtic Design:

A Goblet with carved Celtic knotwork:

Another Cool Goblet:

      Then over the holidays I went on my honeymoon to Ireland. While there we went on a whirlwind tour of the sites of Dublin and Galway, and saw many interesting Celtic decorations and designs. While I found the spray-painted sheep entertaining they weren't particularly inspirational. However, the floors, walls, furniture and even the gardens were covered with Celtic designs that interested and excited me:

The Floor of St. Patrick's Cathedral in Dublin:

Mantle Carving from the King's Head Pub in Galway:
(The carving's dated from 1612)

Celtic Cross with Spiral Designs near Galway:

At Dublin Castle Gardens
Even the Gardens and Walkways were inspiring!

Another Carved Celtic Cross
from St. Nicholas Church in Galway.

Queen Victoria's Table in Dublin Castle
(My next woodworking project, maybe?)

      It was a wonderful trip, and I came back with a couple of books detailing how to draw Celtic designs and a burning desire to try my hand at it.
      The first efforts were pretty bad; I’d tried tying clay ribbons into the simplest types of infinity knots, but they would crack or fail to adhere to the body of the mugs I was attaching them to:

Early Celtic knot:

Another of my early Celtic knots:

      I slowly got the hang of tying the knots, then I began laying a cloth or paper pattern over the clay body, and carving the rough design, then adding more details as I attached the clay carving to the mug.

Celtic knot #10:

Celtic knot #12:

      Of course, I also ran into the never-ending problem of glazing. These two were supposed to be red, but even after 7 years red glazes still give me a lot of trouble.

Celtic knot #16:

Celtic knot #19:

      Sometimes as they heat up and liquefy the glazes will run, and they can obscure the design, like on these two:

Celtic knot #20:

Celtic knot #21:

      Lately, instead of attaching extra clay knots onto mugs I’ve started to throw thicker pieces (which seems like taking a step backwards) and carving the designs into the clay body itself. The results have been good so far:

Celtic knot #17:

Celtic knot #22:

Celtic knot #23:

      For the last month or so I’ve developed a new technique, based on some of the nice glazes that I’ve been using for the past few years…
      I’ve started carving celtic knots and other neat designs into the clay body, then drying and firing the pieces like usual. When it’s time for the glazing and second firing, I’ve begun filling the grooves in the piece with a dark glaze, then sanding off the excess glaze until only the carved design shows, then dipping or spraying the entire piece with a clear glaze.
      The result: it looks as if I’ve drawn the design onto the piece (if it works out—sometimes the piece cracks where I’ve carved it too deeply, or the clear glaze cakes up and becomes opaque, or…)
      Here are some examples of this technique:

Celtic knot #51:

Celtic knot #53:

Celtic knot #17:

Celtic knot #55:

Celtic knot #65:

      FYI: The numbers refer to the number of pictures I've taken, not the number of pieces I've made. I haven't made 65 Celtic knots yet...maybe 25?

      For these ones I tried using a white glaze to fill the design; I can’t decide if I’m happy with the results or not...

Celtic knot #60:

Celtic knot #67b:

      Here's a link to Patty Rau's pottery site:
      Take a look, because she's got a lot of neat Celtic knots and other interesting designs!

RECURRING GOALS, EVERY SEMESTER AND YEAR:

GETTING TALLER:
      I've increased the height of my pieces to the point that I can consistently throw a vase or pitcher up to 14 or 15 inches high. That might not sound like a lot, but consider that my entire forearm, from extended fingertips to elbow, is only 20 inches. Working with one arm inside a piece and the other outside, fingertips pressing together as discussed in the "Advanced Tips and Tricks" section, that means a maximum height of 20 inches, unless I straighten my elbow on my inside arm. There are potters who can throw three foot vases and jugs by using their arm all the way up to their shoulder, but that'll be a goal for the distant future.
      The trick to that last business was the phrase "consistently". That means that the piece I throw should be uniformly thin all the way around, and from top to bottom. That doesn't really happen; when throwing a tall piece the bottom of the wall has to be thicker than the top, to support the weight of clay above it. The trick is to throw a piece, then let the clay dry and stiffen until it's leather hard, then go back and trim the lower part to the same thickness as the top. (clay that's leather hard can support weight better than soft, just-thrown clay, though it can still flex and crack, as I've unfortunately learned.) Thanks partly to better finger placement, partly to improved trimming techniques, and largely to lots of practice I've gotten better at making tall vases and pitchers, and making them thin enough so they don't actually weigh a ton, especially when filled with liquid. Still, I know there's room for improvement, and I'll keep working on it. (Go to the Ceramics Pieces section here or by clicking on the link at the left for a look at some of the vases and pitchers that I've made in the past year.)

LIDS:
      Lids are tough for a couple of reasons. They are usually thrown from a separate lump of clay than the body of the dish or jar that they will sit on. That means you have to carefully measure, using a calipers, to ensure that the lid is the same diameter as the pot. But that's just the start; clay shrinks as it dries, and sometimes a lid that seemed to fit perfectly when you made it will be too big or small when it and the pot have dried.
      Even if it's the right size in the course of drying the lid might warp or twist (which often happens with thinner or flatter pieces; see the "Advanced Tips and Tricks" section for a discussion of why) which means it won't sit properly on the pot. Or the pot might not dry uniformly, and instead of being circular be oval-shaped, or deformed enough that the lid doesn't fit well. Or....
      In any case, there are many reasons why lids might not fit. Some potters circumvent the problem by making several lids, each a slightly different size, that all match a given pot. When dry they choose whichever lid fits best, and toss the others into the clay reclaiming bucket. I've tried making a spare lid, especially for a piece that I've put a lot of work into, but usually resist that urge. I'd rather practice and get good enough that I can be reasonably sure that each lid will fit the pot it's intended for.
      By the way, lids have to be made at the same time as the pot, so that the lid and pot both dry--and shrink--at the same rate. It's theoretically possible to make a pot, let it dry, even have it bisque fired, and later try to make a lid to match it. But the pot will be dry, while the lid you're making will be wet clay, so you'll always be guessing how much the lid will shrink as it dries. You need to be really skilled and experienced to guess that and be right. Conversely, if both the pot and the lid are made at the same time from the same batch of clay, and presumably have the same moisture content, you can make them to match each other when both are wet, and as they dry they will (hopefully!) shrink at the same rate and still match when they are dry.
      Once the lid and pot are leather hard, you have to add a handle to the lid (sometimes to the pot, too). The potential problem here is that the handle might not adhere well to the lid, in which case it'll crack when fired. Or the lid might have dried nice and evenly so far, but when you add the weight of a handle it might deform as the drying continues. Or the lid might be nice and circular, but the lid wasn't quite centered when you attached the handle to it. Or...
      Peter and Lou have given me lots of advice and suggestions about lid shapes and techniques. Your pot might have a flange inside it below the rim, to hold the lid. Or the lid might have a flange inside to hold it on the pot. The lid might be a flat "hockey puck" (as Peter calls them) or might be an inverted bowl on it's own. Or it might be thrown as a double walled bowl, or...
      There are a thousand different possibilities, which means lids can be a lot of fun and showcase your creative side...as well as being incredibly frustrating.
     

Here's a collage of some of the lids I've made in the past:

      For a better look at some of the lids I've been making go to the Ceramics Pieces section here or by clicking on the link at the left.

SHAPED BOWLS:
      In the past I've played around with bowl shapes, making a few square or triangular bowls, even a few swirled and fluted ones. But in 2007 I began really getting interested in the possible shapes for bowls. This was because someone in the studio put a poster up on the wall, right next to my favorite wheel, which showed a number of different types of bowls. There were fluted rims, scalloped rims, roped rims, swirled rims.... There were triangular sides, squared sides, inverted sides, grooved sides....
      I suppose it was a natural progression from the sculptural faces I'd been making, but I suddenly began making a lot of different shaped bowls.

Here's a collage of some of the shaped bowls I've made. Right now I seem to be favoring the three-cornered ones, but that's because these are all individual soup-sized bowls. I'm sure I'll start shaping and sculpting larger bowls at some point, which might lead to 17-cornered ones. You can get a better look at these and some of my other bowls in the Ceramics Pieces Section.

MATCHED PIECES:

      Over the longer term I hope to improve my ability to make identical pieces. It would be nice to be able to make a set of something, even just a set of two matching bowls or mugs. But that's really tough; even skilled potters have a difficult time throwing identically sized plates, bowls or mugs.
      You have to start by weighing the clay, and selecting identical lumps to throw. Because of differences in moisture content weighing clay is more likely to give you identically sized lumps to start with than measuring some other way--but even then, a two pound lump of really wet, water-laden clay might be much smaller than a two pound lump of dry, stiff clay.
      Then you wedge the lumps and throw them; but no matter how carefully you try to match them there are likely to be small differences in height or diamater between the pieces. Peter tells me that even experienced potters, if they're asked to make a set of 8 plates, for example, commonly make several extras, sometimes twice as many as requested. That's partly because pieces might crack or warp during the drying and firing, but mostly to insure that they can pick the most closely matched pieces to make up the finished set.
      The most common solution to making identical pieces is molding them. The sets of pottery you buy at Target were almost certainly made from a mold, which ensures that a bunch of identical pieces can be produced. Of course, making the mold itself is a time-consuming and cumbersome process, so it only makes sense if you're going to make dozens or hundreds of identical copies of a piece.
      The other solution, and the one I plan to tackle, is simply to practice.

MY EVENTUAL GOAL:

      Lastly, somewhere down the road I hope to develop my skill enough to make intricately carved and sculpted scenes and designs.

My Dad's heirloom Stein

The other side of My Dad's Stein

My eventual goal is to be able to make pieces like my Dad’s prize heirloom; a gallon beer stein that his great-grandfather brought from Germany long ago. It’s carved with scenes of German barbarians fighting the Roman legions, as well as trees, leaves and vines. I’ve always been fascinated by the intricate detail on it, and would love to be able to make such a beautiful piece someday.

ADVANCED TIPS & TRICKS:

With your inner fingers above the outer ones:
The clay is forced inwards by
the lower fingers as you go up

With your inner fingers below the outer ones:
the clay is forced outwards as you go up

COMPRESSING:
      Another problem I’ve been working on is compressing. When thrown, clay has a high water content, and as it dries the water evaporates and gaps or cracks in the clay appear. To combat that, the clay has to be compressed, making it denser, squeezing out some of the water and eliminating or reducing the gaps the evaporating water will leave behind.
      The action of throwing naturally squeezes the sides of a pot, compressing the clay. It’s very rare for the sides of a piece to crack while drying, unless they’re either very thick or very thin. That’s not true of two parts of a pot: the bottom and the rim. Most cracks occur there, because the clay hasn’t been compressed as much by the throwing.
      To prevent cracks on the bottom the clay has to be compressed, either with the side of your hand, or a sponge, or a flat tool. The problem with this type of compression is two-fold; if you press harder in one spot than another, your bottom will be thinner at that point, and might break through, warp during the drying or crack in the firing. Also, if you use a sponge to compress the bottom the sponge will pick up fine particles of clay, leaving only the coarser elements. A number of my cups and pots have a rough, pebbled surface to the inside bottom, because I used a sponge to compress them.
      The solution to that is to use just your fingers, but I've found that tends to make the bottom uneven, leaving bumps and ridges where the gaps between my fingers were. Using the sponge tends to make for a smoother bottom. Instead I try to compress the bottom as quickly as possible, so fewer particles are removed by the sponge, while still compressing it as evenly as I can. I also pour an extra bit of glaze into the bottom of a piece, which will fill in the rough spots—but that can be tricky because if the glaze is too thick it will crack.
      Compressing the rim of a piece is more problematic. Simply squeezing the rim will make it thinner and taller, while the very edge will remain rough and is likely to crack. Some potters use their fingers to squeeze the rim of a piece inwards, while using a thumb on the top to press it downwards so the rim doesn’t become too thin. That’s VERY difficult, because applying pressure to the top of a piece can create bulges and make it lopsided lower down.
      One solution I’ve been trying is to use a small piece of chamois leather, soak it in water, and wrap it over the rim. Then I spin the wheel while pulling lightly on the edges of the leather; this condenses the rim edge without thinning it. It’s still possible that bulges will appear lower down, since the leather still pushes down on the top of the pot, but it seems to work better than just using your fingers, and the leather doesn’t pick up clay particles as readily as a sponge does.

TORQUE:
      Torque is the rotational force applied to a clay body by the turning wheel. It’s caused some problems for me in a number of ways.
      Normally the wheel spins clockwise, at a variable speed controlled by a foot pedal. As I center a lump of clay I spin the wheel rapidly, to eliminate any minor lumps and bumps in the clay and smooth it completely. Then as I begin to throw and pull up a piece I slowly decrease the speed, because the wider and taller a piece gets the more impact a minor push or jiggle of my fingers will have in shaping it. By the time I get to the top of a piece the wheel is turning very slowly.
      Problems come up if the clay is too dry; your fingers will stick to it and the clay will twist or tear. I’ve had several pieces that ended up lopsided or twisted because my fingers stuck. Some potters coat their hands with oil or Vaseline to keep from drying the clay out, but that creates other problems when the oil is absorbed by the clay; it increases the drying time of the piece and inhibits the ability of the dry clay to absorb glaze.
      The other problem arises while pieces are drying; during the throwing the clay is twisted by the torque, particularly near the top, and while it’s drying the piece will slowly untwist. Peter demonstrated this to us by throwing a tall piece, then drawing a series of vertical lines on it and leaving it to dry. When the piece was dry the lines had twisted into a series of narrow “S” shapes because the top of the piece had untwisted.
      If the pot is symmetrical this isn’t noticeable. When it is most noticeable is if you are throwing an addition piece, such as a spout for a teapot or pitcher. The spout gets twisted, and while it’s still wet it has to be attached to the side of the teapot. Then it will untwist while it dries, and you may come back to find a spout that looked straight when you’d attached it now looks twisted and warped. I’ve made several teapots with spouts that look like bent noodles because of this problem.
      There are a couple of fixes to this that I’m working on. One, used by expert potters, is to regularly reverse the wheel’s motion, so the clay gets twisted both ways during the throwing. Hopefully, the torque applied when the wheel is spinning clockwise will balance the torque applied when it’s going counter-clockwise, and the piece will dry straight.
      I’ve tried this, but found it too difficult; when the wheel’s direction is reversed you have to reverse your hands and finger placement, something I’m not talented enough to do easily.
      The other fix is to try to estimate how much torque was applied to the spout, and attach it at an angle, so when it’s untwisted it will look straight. This can be tough; thinner pieces twist, and untwist, more than thicker ones, and more torque is applied at the top of a piece than the bottom. It’s a guessing game that I’m still working on learning.
     The last option is to make spouts without using the wheel, by coiling or handbuilding. The problem I have with that is that I have big hands, so my handbuilt pieces tend to be thicker than thrown pieces. It doesn't look good to have a beautifully thrown, thin teapot with a thick, heavy spout attached.
      Hopefully, I’ll find a good, consistent fix to the torque problem soon.

MY BASIC POTTERY TUTORIAL
WHAT IT TAKES TO BE A POTTER:
      Working with clay means getting dirty. I once saw a documentary about pottery in which some famous English potter was throwing teacups while wearing a three piece suit and tie—and didn’t get anything but his fingers dirty. Perhaps when I’ve been doing this for 30 years I’ll be a “clean” potter, but for now when I go to the studio I come home with clay spattered on my arms, chest, legs, hair, etc.
      If you’re squeamish or fastidious ceramics probably isn’t for you.    ( FYI: kaolin, one of the main elements in clay, is also a stabilizing element used in a lot of foundation makeup. You may get dirty working with clay, but it won’t damage your skin...well, actually...most potters I know complain of two regular injuries; dry skin from working with clay, and cracked fingernails from the turning wheel.)
      Working with clay also requires WORK. I’ve come home some nights after just a few hours in the studio aching from head to foot. My shoulders ached from kneading clay, my arms ached from throwing it, my back ached from hunching over the wheel, and my legs ached from keeping the wheel turning. If you think of Demi Moore in the movie “Ghost” when you think of pottery, be aware that if she’d really been a professional potter her arms and legs would have rivaled a linebacker’s. (Yes, I’m aware that some potters look dainty or delicate—but find out what they do. If they make tiny teacups or little soup bowls that doesn’t require much strength—but a potter who regularly makes large pieces will get muscles doing it.)
      Working with clay also requires a lot of patience. Even in the best of circumstances the time lag between starting to make something and actually having a finished piece to show requires two weeks. Throw in all the frustrations and aggravations which come along: clay that’s not properly mixed, or too stiff, or too wet, or has air bubbles; pieces that crack while drying or firing; glaze that runs or globs or spits; and so on. This is not a hobby for those who can’t deal with frustration and failure, or who require instant gratification.

My tool kit includes:

• Sponges to keep clay moist, as well as for cleanup
• A needle tool, which looks like a narrow knitting needle and has many uses when centering and trimming a piece.
• A series of different sized trimming tools to remove excess clay
• A wire tool, to cut clay lumps or remove a finished pot from the wheel.
• A series of wooden and metal scrapers, of different sizes and shapes
• A thin knife for cutting clay slabs when slab building.
• A metal fork for scoring clay slabs being joined
• Various sized brushes for applying glazes
• A mesh sieve for sieving glazes being mixed, to eliminate clumps and lumps
• A number of different carving tools--these are small chisels with different tips useful for carving lines or designs, or otherwise decorating a piece
• A rolling pin for rolling slabs of clay
• A piece of chamois for smoothing rough clay
• An old kitchen grater for shaving thicker pieces
• A stack of old newspapers--these are crumpled and used to support pieces while drying, to keep them from drooping under their own weight (my handles and teapot spouts are notorious for slumping)
• Several wooden boards to keep pieces on while drying, so they can be moved around the studio to the glazing area, kiln room, etc.
• A pile of plastic bags to wrap clay and keep it moist
• A lazy susan, for slowly turning a piece when I’m carving or glazing it.
• Rags for cleaning up

The studio supplies the clay, glaze elements, potters wheels and kilns.

Some photos of me throwing clay:

Wedging Clay

Still Wedging Clay

Ready to Start

Centering a lump of clay

Throwing 1

Throwing 2

The most important tools

Throwing 3

Throwing 4

The Thrown Pot

Cutting a cup off the wheel with the wire tool

Smoothing some rough spots on a bowl
that's dried to leather-hard

No matter how hard you work at it
problems come up: this bowl
cracked while it was drying

RAKU WORK:

I'm not fond of Raku, though it has it's advantages. The clay is much coarser than stoneware, with a lot of grit (small stone chips) and grog (old ground up bisqueware) added to help it withstand the shock of sudden temperature changes. Raku pieces are made and bisque fired in a regular kiln, then glazed with special glazes and heated rapidly to the melting point of glass, causing the glaze to fuse with the clay.

The problem I have with Raku is that pieces aren't waterproof or the glazes food safe, so you can't really make functional pieces with Raku. Still, as a sculptural medium Raku work can be much thicker than stoneware, and you can get much more vibrant colors from Raku glazes.

Oakton sponsors several Raku firings a semester, and I must admit they're neat to watch and fun to take part in. Here are some photos of a Raku firing:

Pieces being loaded into the Raku kiln

The Raku kiln is fired
to between 1,000 and 1,200 degrees
for about 30-60 minutes

The Raku kiln is opened and the pieces quickly removed;
they're covered with a trash can to stay in an airless environment while the glaze "cures"
Sometimes newspaper or other combustible material is added
which causes carbonization highlights in the glaze.

NOTES AND THOUGHTS ON PIECES I'VE MADE:

GLASS SHARDS:
      One of the neat techniques I've toyed with has been working with glass shards; several of the other artists have been doing that and I've finally gotten around to trying it. Beads of colored glass or shards and fragments from broken bottles are scattered on the bottom of a piece, or embedded in the sides, and as the piece is fired the glass melts and runs, spreading out and giving a cool, colored pattern. According to Peter there are a lot of dangers in doing this, ranging from bad reactions between chemical colorants in the glass and in your glazes to glass that cracks and leaves sharp edges as it cools. But I've just started to play with this technique; not sure if I'll continue with it yet.

FACES AND SCULPTURAL PIECES:
      One trick I’ve been trying involves shaped vessels: last year when I made face cups I would throw a plain cup, then attach extra clay for the noses, lips, etc. The result might be a good face but the extra clay would make the cup heavy, and if the nose or lips made the piece too thick it would crack in the firing. This spring, on Peter’s advice, I’ve been throwing thin mugs, then while they’re still flexible I’ve been shaping the nose and facial features from the inside, pushing and molding the piece into the desired shape before carving the finer details of the face. The results have been face cups that might look similar to what I made last year, at least on this website, but are actually much thinner and lighter.
      I’ve also been making more sculptural pieces; most obviously with the “feet” bowls. This involves throwing a bowl with a very large “foot”; the technical term for the ring of clay at the base of a bowl that holds it steady on a table. Then I would carve the foot until it actually looked like a pair of human feet (or, in one case, animal paws). I’ve also tried to shape some bowls into faces, but wasn’t pleased with the results. “It looks like a rat,” Diane commented, so I added whiskers and tails and made several bowls that look like rats. Hey, I’m an English teacher, I’m allowed to be literal at times….

MIXED CLAYS:
      Another new trick has been to try “mixed clay” pieces. This involves wedging a lump of buff clay, another lump of red clay, and cutting, laminating and combining the lumps, then throwing a piece. The result, if it’s done right, is a mug or bowl that has swirls of lighter and darker clay evident. It’s harder than you might think; the two clays have to be the same consistency and moisture content, or else when you’re throwing it the piece will fall apart—imagine trying to combine a thick, stiff jello with a thin yogurt and you’ll get the idea. Also, joining the two clays can add extra air bubbles, which will become apparent when the piece shatters while being fired.
      One other drawback to this mixed clay technique is that, ideally, the different colored clays should be seen in the final product. Unfortunately, most of the glazes I’ve been using are completely opaque. To allow the swirls of different colored clays to be visible you have to use a semi-transparent glaze, but those are more likely to have problems. If the glaze is a bit thicker here than there, it will show up in a difference in the coloring. So far I’ve developed only one glaze, a greenish one called “rhonda’s celadon” that can showcase the different colored clays and yet fires to a consistent texture and color without cracking.

Here's a photo of one of my mixed clay mugs.

FLATWORK:
      I have tried to make a number of plates and platters and have had no luck; every one has either cracked or warped in the drying. In particular I wanted to make a “swimming pool” complete with swimmers and divers sticking out of the water, and have tried 4 times to do that; each time the piece has either buckled or cracked. That’s because flat pieces tend to dry unevenly, and the bigger the piece the more problems will crop up.
      When clay dries it shrinks, and the edges of a platter will dry first while the middle remains wet and heavy. In trying to shrink, the edges will either crack or bow upwards, warping the entire piece. Peter’s advised me on some tips to try, such as weighing the piece down with pebbles to keep it from warping, or coating the edge with wax so it retains it’s shape while the middle dries, but I haven’t had time to try any of those yet. That might be a project for next semester.

Here's a photo of one of my attempted swimming pools,
you can see that it cracked along the edge.

Here's a photo of another swimming pool;
though a poor picture, you can see
how the tray bowed and warped while drying.

      I'll be adding more notes and photos about specific pieces and problems as things move along this year.

Lake Side Pottery Website

Professor Marvin Bartel's Learning to Throw Pottery website

You can also take a look at my Instructor, Peter Hessemer's, Website:
Peter Hessemer's Home Page