Fairy Houses

Well, it’s been AGES since I posted here. Busy summer, lots of good stuff, a little–um–less than good stuff–life. Here are some pictures of my daughter and a friend making fairy houses. We also made this project with our class of little girls, but kids’ classes being what they are, we were too busy to take pictures of that. When the kids’ fairy houses come out of the kiln, I might post some pictures of them, too.

Because it’s so difficult for little kids (and others) to make a decent coiled pot, I’ve thrown on the wheel and bisque fired a number of forms for them to use. Coiled or puzzled pots are easy to make either on the inside of these bisqued forms, or on the outside.

If you decide to throw some forms, either for your own use or for teaching others, be sure you make the walls slope outward slightly, and make them ABSOLUTELY straight. Use a rib or a slat of wood to make sure.  If the walls curve inward at any point, it can make removing your coiled pot very difficult.

In the photo, you see my daughter in the process of adding a coil. I have the kids start these pots by making a pancake-shaped slab with their hands, beating and throwing it on the canvas table cloth. It should be a bit larger than the base of the form they’ll be using, and maybe 1/4 to 3/8″ thick. Coiled pots tend to get S cracks in the base, and this helps to prevent that from happening. Snug the slab over the base of the bisque form. If there’s too much time between this step and the next (adding the first coil), you’ll want the kids to score the edges of the slab and paint on a little bit of water. I DO NOT use slip for this, as the slip tends to stick the pot to the form.

The coil in the photo is about right for a nice, thin pot, but if the kids make theirs twice this diameter and all lumpy, that will work almost as well. Watch them closely, as they’ll tend to smooth the outside edge of the coil down to the bisque form, creating a knife edge. You want the edge nice and fat–at least 1/4″. You don’t need to keep scoring as you go along. It’s enough to score the edge of the pancake. This pot needs to be finished in one sitting, because the bisque form will dry the clay out even if you wrap it in multiple layers of plastic. I just add the coils in a spiral as I move down the mold/form, and when I run out, I make another coil and add it in where I finished the last one.  If it takes a long time to start adding the next coil, you could score just the bottom (leading) edge of the pot and paint on water before starting to add the next coil.

Don’t let the pot go too long, though, especially if you’re working on the outside surface. The clay you’re adding can shrink and then you’ll have to cut your pot to get it off the form–Bummer! One thing, though–if this does happen, try just cutting the door for your fairy house. That may be enough to release the  pot, and it could save you having to stick the whole thing back together.

When you get to the bottom of the form, cut off any excess with a needle tool held perpendicular to the wall of the pot. Just drag the needle tool right around, using the lip of the form as your guide–no need to saw. It will slice right through and make a smoother cut if you do this in a smooth motion. You should now round the edges (both the outside one and the inside one–(next to the form)). Gently pinch the edge just a little bit between your fingers to give it a rounded contour. Don’t stretch it out!

Before you take your pot off the bisque form, add any textures you would like. The pot in the picture was textured with a tree bark mold someone made of rubber mold-making compound. You can also use texture stamps–either purchased or homemade and bisque fired, natural items such as rough rocks or sea shells or bark, etc. You can use fondant rollers (look in the cake decorating section of your craft store), lace or other textured fabrics . . . the list of possibilities is endless. Access your imagination and have a look round the house or classroom or back yard.

Once you’ve added the texture, you can remove the pot from the bisque form. Hold the end of the pot with one hand and have your other hand inside the form. Give a little shake or twist or rap, and if the pot hasn’t shrunk too much, the form will slip right out. If you need some help, don’t be shy about asking. Sometimes two sets of hands are better for this job–especially if your form (and hence your pot) is large and difficult to hold. Gently set the pot down on its open end. Since you’re making a fairy house, this will be right side up. If you’re making something else–a flower pot, for example, you can set it on its bottom.

At this point, I have the little kids “glue” their fairy houses to a textured slab to form the fairy’s yard. This makes it harder to eventually light up the fairy house, but it does stabilize the base of the pot and makes it easier for the kids to work with the project. I have them cut their “yard” into a free-form shape a little bigger than the fairy’s house. They like to add mushrooms and things to it. I use a 3/8″ thick slab for this, and I let the kids choose a texture and feed it through the slab roller. If you haven’t got a slab roller, that’s okay, but I’d have some slabs rolled ahead for the kids to texture if you want them to finish their house in one session.

The fairy house needs a chimney. You can make one from a slab rolled into a tube, or you can make a marshmallow-shaped piece of clay and then poke a hole in it from end to end with the handle of a paintbrush or whatever’s available. With your paintbrush handle, enlarge the hole while thinning out the walls a bit and voila! You have a fairy chimney. Cut a little hole in the roof–wherever you want to let smoke from your votive candle escape–and attach the chimney on the edges of the hole. Or if you prefer, you can attach the chimney and then poke the hole. Don’t forget to scratch and moisten both edges where they’ll be attached. (The brown strip you see on the table in the above photo is the tree bark mold Cheri used to texture her fairy house and chimney.)

Here you have a photo of Cheri’s friend, Emily, deciding where the chimney of her fairy house will sit. Once you’ve decided where you want it, mark it by tracing lightly around it with a pointed object like a needle tool or a sharp pencil. That way you know where to score and poke the hole. In the upper left, the purple thing you see is a fondant roller with which Emily textured her fairy house.

You can now decorate and add windows, doors, etc. Remember to score and moisten and firmly attach all additions. Cheri eventually put her door on top, since she figured the fairy would want to fly in and out, and it would make for a more secure perimeter. Of course, those are pretty big windows . . . .  If you want to insert a votive candle, make sure the kids make at least one opening that will be big enough (and don’t forget that your clay will shrink–ask the supplier for specific percentages). Otherwise, you can cut a hole through the slab inside the house so that you could just set it down over the candle–in the same manner as these open-based houses will be used.

When the houses are finished, I’ll post some more photos as an update. Meantime, here’s a fairy house made from a pinch pot that I formed into a pumpkin shape.

Watercolors are Fun

Hi Everybody

I know it’s been a very long time since I’ve posted anything here. (And I started out so well!) I’ve gotten a new camera, though, so I’m excited about getting back into the swing of things soon. Meantime, my latest foray into watercolor has kept me interested. Here are a few photos of recent pictures:

Watkins Glenn

Snowy Creek

The Danger Within

We’re doing “Mushroom Houses” . . . and the little creatures who call them home . . . in my pottery class. These are similar to the one in my mast head photo. I’ll post some pictures and maybe a wee tutorial soon.

God bless, Cindy

Hi Everybody!

Sorry it’s been so long since I’ve posted–been having camera problems, but I expect to have that resolved within a couple of weeks. Meanwhile, I’ve been playing around with watercolor. This is a fairly new medium for me, though I’ve dabbled occasionally. Here’s a picture I did for a project at “I Draw & Paint” forum. It’s small–5×8, on Strathmore paper 140 lb cold press. Like I said, I don’t do a lot of this, but it’s fun.

Snowy Fjord: December Challenge: Lapland

Pottery Pigs

I just finished teaching three separate 6-week pottery classes. One of our favorite projects was these Piggy Banks:

The kids did a spectacular job . . . don’t you think? And some of them were very young. The boring one with the “normal” eyes is mine. I was going to teach the kids to do eyes like that, but they got way out ahead of me, and I’m so glad they did! They required a lot of help inputting the bodies together, but they figured out on their own how to do the embellishments such as eyes and noses and tails. The pigs’ legs are coil-built and were added to the bodies along with the eyes and such.

To make these pigs, I had the kids pound thick clay slabs over some bisqued bowls I had made earlier. (I had trimmed the bottoms of the bisqued bowls round so that they could be used either as slump or hump molds.)

They each made two bowls.  We hardened the clay in our little cheapie microwave oven for one minute at a time, a total of two minutes per piece, with a waiting period between hardening sessions. The first time in the microwave, you can leave the clay on the bisqued bowl, but you should take it off the bisqued bowl the second time, or it might shrink too much and crack.

Once both bowls are hardened, you can scratch and slip and join the two pieces to make one hollow form. This is where the kids needed the most help. It’s a tricky operation, especially for little hands. Adding the features is the fun part. Mostly, we did that at a second session (our classes are an hour and a half). When the pigs’ bodies have set for a week, even wrapped in plastic, they will be stiffened up a little and a lot easier to work with.

Be sure that any hollow enclosed spaces (such as the pig’s nose) have a hole in them. Nostrils are a good place for this. Also, if your kids use any thick pieces of clay, poke some air channels in them with a needle tool to allow moisture to easily exit the piece. I try to do this in a spot that won’t be visible, but really, these tiny holes seldom show through the glaze.

The piggy banks have a slot in the top for coins and a hole in the bottom to let kids get their money out. You won’t want to break these pigs! You can get stoppers at most ceramic suppliers. For cone six stoneware, the total shrinkage of the clay will be usually around 12-13%, but ask your clay supplier. You need to know for sure. Measure the circumference of your stoppers (make sure they’re large enough to let quarters fall out) and add 12-13% or whatever your clay shrinkage percentage is, then make a hole that size. Don’t make it too big–if it’s a wee bit small, that’s okay because the stoppers have some give to them. I gave the kids a patern to cut around.

When you make the slot in the top of the pigs, be sure to allow for shrinkage there, too, and make it wide enough as well as long enough.

Oh, and when figuring out how big to make the coin holes, you need to keep in mind one more thing. Cone 6 clay has accomplished half of its shrinkage when it has reached firm leather hard stage. Therefore, if you have allowed your banks to reach leather-hard stage before cutting the holes, you need to add half the shrinkage percentage instead of the total shrinkage. So if your supplier tells you that your clay will shrink 12.5%, and your clay has reached firm leather hard stage, it has already shrunk 6.25% (or thereabouts).

If you find that some of your kids have cut their holes a little large, you can get a larger stopper or a tapered stopper like a natural cork. If you’d rather not do that, you can add a bead of silicone around your stopper’s rim, and smooth it to a taper and let it dry. This will most likely be sufficient to fix any loose stoppers.

This isn’t my usual detailed tutorial, and if you have questions that I haven’t addressed here or covered in an earlier post, feel free to ask. I had really intended to only publish the photographs, but this is such a fun project, I thought you might want a few more details.

God bless,

Cindy

Glaze Firing Pottery

You’ve got your pottery all covered in promise–that is to say, glaze. The glaze will either make or break your piece, so be sure to follow my suggestions in the post on glazing as well as reading and following any instructions that might have come with the glaze, stack your kiln carefully (nothing touching anything else, no glaze touching shelves or walls), pray, and stay within reasonable proximity to the kiln.

We’re talking about electric firing here, btw. Choose a day in which you don’t expect the power to go out. That might sound obvious, but starting your glaze kiln on a dark and stormy day could have unfortunate complications. First, the barometric pressure does make a difference in the outcome of your firing. Second, if you’re using a computer controller, lightning is not your friend. You’ll be biting your nails until you’re able to turn both the kiln and its breaker off (or pull the disconnect switch). Third, even if the power just peacefully dies without a surge, it’s better not to interrupt a firing. Doing this can have permanent consequences to your wares–sometimes good, more often bad.

Read my precautions about kiln venting given in my post on bisque firing. In fact, read the whole post again. There’s a lot of stuff there that applies equally to glaze firing. Directions for firing differ from kilns controlled by a sitter to kilns controlled by a computer device and its requisite pyrometer. (If you don’t know what I’m talking about, read the bisque firing post.) I’m going to put the instructions for the sitter in black and those for the computer controller in italic.

One caveat: make sure your glazed ware is dry. If you think your ware may have residual moisture left over from glazing, start your firing on low power for an hour or so.

• I often start a glaze kiln on high power and leave it there for the whole firing, but the sitter kiln I use is at the art & science center where I teach, and I’ve made it a point not to have any sensitive glazes there. If you have glazes that need a soak at the peak temperature, you might want to turn down one or two of the elements when the firing is nearly done. You’ll know this from your past records and from the behavior of the cone packs you have placed in the kiln.

• Some people do recommend a slower start, even for a glaze kiln, but I typically start my kiln out at full power–that is, I tell it to heat at 500 degrees Fahrenheit per hour. It will be able to do this at first, but soon it will have to slow down because it can’t deliver enough power to rise that fast. The speed at which your kiln is able to heat depends on the elements, power available to them, size of the kiln, ambient temperature, and probably the phase of the moon.

• If you’d like to soak your sitter kiln, wait until the target cone (in my case, 5 or 6) just begins to bend, then turn one or more elements down to medium. Leave them like this for the duration of your desired soak (usually about 30 minutes or less), then, if necessary, turn them up again. Ideally, you shouldn’t have to turn them up. You should learn, by experimentation, to turn the elements down just enough so that you will slow the rise of the kiln, but not stop it.

• If you don’t yet know what temperature will cause your target cone to bend, you’ll need to watch the shelf cones closely as the kiln approaches peak temperature. A thermocouple may read 2260 degrees F. and yet the cone 6 on your shelf may show that the firing has achieved cone 6 temperature/heat work. Set the controller to slow your firing down when it reaches about 50 degrees below your target temperature. I tell it to fire at 50 degrees an hour at this point. Then, if you like, you can also program a soak at peak temperature of 15-30 minutes. You don’t want to soak too long, or your glazes will be in danger of running off onto the kiln shelves, even if you haven’t overfired them. At these temperatures, they will have become a viscous liquid, like molasses or honey, and too much time allows them to flow into places you’d rather not have them go.

• For all practical purposes, you are done firing if you’re using a sitter kiln. Leave the vents turned on and keep an eye on things until the kiln has cooled enough not to present a danger of fire, then just allow it to cool naturally. When it is no longer warm to the touch, you can check to see if it has cooled enough to unload. Ideally, you should wait until ware and kiln furniture can be held in the bare hands for any length of time without discomfort from heat. Once you’ve been doing pottery for a while, you can think about turning the kiln back on at around 1900 degrees and thus slowing down the cooling to encourage microcrystaline matte glazes, but that’s a very advanced technique without a computer to help you and requires knowledge you can only gain from experience.

• If your glazes are all glossy ones, you, too, can just turn the kiln off and let it cool at this point. If you have microcrystalline matte glazes in the kiln, set it to fire down. It should be allowed to cool naturally (just program in a high number–say 500) until it reaches 1900 degrees. You should then have it cool at 100-200 degrees an hour until it reaches 1700 degrees. At this point, you can allow the kiln to cool naturally. Just don’t program another ramp, and it will end the firing. As above noted, it is best to allow the kiln to cool until ware can be easily and comfortably be handled with bare hands. You’ll have to learn by experimentation how fast to cool the kiln during the 1900-1700 phase, and it will likely differ from glaze to glaze. A longer cooling makes a more matte glaze, but you can cool so slowly that normally buttery mattes will become almost dry, and that may or may not be what you were after.

A quick word about unloading a hot kiln. I confess that I have unloaded kilns that were so hot they made my welding gloves smoke and I had to take them off and let them cool before I could continue. This is considered bad practice, but after being patient for about so long, it’s sometimes more than I can do to be patient for another six hours or so. So . . . if you choose to ignore my good advice (as I sometimes do) . . .

• Be sure to set your hot pottery on a suitable surface–like the lid of another kiln or a fire brick or a fairly warm kiln shelf.
• Remember that thermal shock (sudden change of temperature) is the mortal enemy of pottery and glassware. Do not allow your pottery to contact a cold surface. If you have a history of Raku, know that raku clay is especially formulated to withstand thermal shock, and it sometimes breaks anyway.
• Do not remove pieces with large flat bottoms from the kiln–plates, platters, etc.–because they will break. They’ll crack right in two. I promise.
• Do not set hot kiln furniture (or hot pottery) on a vulnerable or a cold surface.
• Wear protective clothing. The best heat-proof gloves you can afford, long-sleeve, natural fiber shirt, and tie long hair back.
• Finally, really–don’t do it. You can wait. The pottery isn’t going anywhere.

So, I’m afraid this last bit of advice is like handing a kid a condom and telling him not to have sex, but you’ll make your own decisions about this sort of thing. I did. So, you might as well learn from my mistakes so that you can go on and make new mistakes of your own.

Your pottery is out. Some of it is beautiful; some of it disappointing; and some of it may even (God forbid) be stuck to the shelf. Most of it will need sanding on the bottom so that it won’t scratch your furniture. Just use regular sandpaper from the woodworking section of the hardware store. I like 80 grit, but any coarse grit will work. If you have a power sander of any kind, you can use that, but be careful and follow appropriate precautions given by the manufacturer of the tool.

If you have glaze drips on your pottery or on your kiln shelves and furniture, you can use an angle grinder with a masonry disk to clean them off. Again: thick leather gloves, goggles, long sleeves, tie back your hair, use ear plugs, dust mask. Really! Especially the goggles and the gloves and the hair tie.

Making pottery well requires a long and patient learning process (or at the very least, a helpful teacher/mentor.) I know all of this sounds complicated, but it’s no more so than any other skill and a lot less than many. It’s a lot easier than building a house, for example. Enjoy the process; don’t get too attached to any individual piece; remember it’s just mud and you can make another one.

God bless,

Cindy

Pottery Photos II

I’ve been doing a lot of talking lately about technical stuff. My next post will be on conducting the final glaze firing using an electric kiln, but I thought you might like to see a few photos of finished pottery for a change–get an idea of what you can expect from that glaze kiln (if it turns out well). If you click on the photos, they’ll either take you to my Etsy site (if the piece is for sale) or to my Flickr site (if it’s not).

This jar was wheel thrown and is intended to hold jewelry or
homemade lotion or such. I painted wax resist on the gallery and the
lid ring and fired the lid in place on the pot. If you fire the lid
separately, it will sometimes warp and not fit the pot after glaze
firing, but if you fire the two together, you have to make absolutely
sure there are no traces of glaze anywhere the two pieces will touch.

I first threw this bowl on the wheel, but I didn’t like it. So I
fiddled with it until it looked like this. I really love it now.
This is not to say you should never give up on a pot, but don’t give
up too easily. You never know what you might make of it.

After the first glaze firing, I didn’t like this fellow’s
shiny skin. Sometimes, if you refire a pot to bisque
temperature (just put it in with a bisque load), it will
give the glaze a chance to “devitrify” or form micro-
crystals, matting the glaze. In this case, I was really
happy with the results.

This vase makes me think of something Snow White
or Briar Rose might use for a bouquet of beautiful
wildflowers–hence the name: Forbidden Forest Vase.

And here are the wildflowers themselves. I carved them
into this cup. The dark brown unglazed bottom is colored with
an iron oxide wash–that is, an unspecified quantity of
red iron oxide mixed into a bucket of water. If your pieces
come out too dark, mix in some more water. If they’re not brown
enough, add more red iron oxide (RIO). You want maybe a cup or less
to a gallon of water, and you’ll notice that you need to stir it a lot.

My daughter made this little guy, while she was teaching a bunch
of kids to make them, too. I was teaching wheel, so I was glad to have
her taking care of the kids who couldn’t get on the wheel (we have only
four wheels and in this class there were 8 kids). They all made cute
puppies and kittens, but of course, non as cute as my little girl made.

I made this mask during a class teaching, guess what? Masks! I sort of
thought he looked like Pan, so that’s what I called him.

Well, that’s it for now. I’ll try to get back to you with instructions and tips for the glaze firing sometime next week. Then you’ll be all set to go!

Until then, make lots of pottery!

Cindy

Glazing Pottery

I’m constantly asked by students (most of them under the age of 12), “Are we going to paint the pottery today?” Cute, and I always hate to disappoint them, but many adults don’t know a lot more about finishing pottery than the kids do.

Pottery can certainly be painted, and many people do that–I do sometimes myself. Here’s an example of a little dragon flute that I sculpted and my daughter painted.

We decided to paint it because Cheri likes the metallic colors she used for little Draquina, and I think she turned out really well. She only plays a quatrain, which is why I have officially coined the term quaturina in place of ocarina.

Anyway, yes, you can paint pottery and no, it’s not some sort of heresy to do so. Typically, you would paint pottery that has been fired to the bisque stage, and if you want to do this, you’ll also want to prime the pottery first with any type of inexpensive acrylic paint.

Most of the time, you’ll be glazing, not painting your pottery, though you might apply the glaze or underglaze with a paint brush. Most potters wait to glaze their pottery until it has been bisque fired, though it can be glazed when leather hard or bone dry.

Mid and high fire glazes are not usually applied to the underside of pottery. They melt and stick the pot to the shelf. If you’re glazing a lightweight piece, you may be able to use kiln stilts to keep a fully glazed piece from sticking, but in general, anything but low-fired pottery is left unglazed where it touches the shelf.

Let’s start by talking about underglaze, just to make things simpler. Underglaze, as you would suppose, is applied under a glaze, usually a clear glaze. You paint on the underglaze with a brush, a sponge, a splattering tool, or whatever you like, and then dip or spray the pot with a layer of clear glaze. Underglazes can resist the clear glaze if you paint them on too thickly, and you’ll end up with a pot that has a matte surface that isn’t very durable.

You can also buy or make glazes that are designed to be painted on with a brush. Glazes are different than underglazes in that they are a complete finish in themselves. Underglazes are not complete in themselves, but must be covered with a glaze. So, the brush-on glazes . . . they come in little jars and you just put them on with a brush. You get a lot more control this way than you would if you were spraying or dipping your pots, but it’s also a lot slower work. Most brushable glazes are designed to be applied in 2-3 coats. They should end up about the thickness of a credit card, so if your glazes are going on thicker than this, you need to thin them out by mixing in a little water.

The most popular way to glaze functional pieces such as cups and bowls, etc., is to dip the pottery pieces in a bucket of glaze slurry. This type of glaze, as well as many of the aforementioned brushable glazes, is not usually anything like the color of the finished product. A gray or dark brown glaze might fire up blue. Green glazes are often colored with copper oxide and are therefore usually green in the bucket, but that won’t tell you anything about the shade of green. White glaze is also white in its raw state, but so is clear, unless it’s been colored blue to identify it and differentiate it from the white. The blue will burn out and will not affect the color of the finished glaze.

Dipping glaze comes in liquid or powdered form. Liquid is obviously easier, but more expensive to ship. It may or may not arrive properly thickened or thinned, but we’ll get into that later. I make my own glazes in 10 kg batches, but if I were buying, I’d either buy pre-mix or purchase 25lbs of glaze (which is a little more than 10 kg). This amount will make 3.5-4.5 gallons of glaze, depending on the formula of the glaze. To mix up your 25 lbs of powdered glaze, you’ll need the following:

1. Five gallon bucket
2. Stirring stick
3. Sieve and stiff brush
4. Dust mask
5. Power drill and 5 gallon paint stirring attachment (optional)

It’s best to work outside if at all possible, as the dust from powdered glaze can float in the air for quite a long time. Otherwise, be sure to work in an area with an adequate exhaust fan–adequate means really, really powerful, by the way. If you can’t secure a suitable place to mix glaze, it’s best to buy it pre-mixed. Here’s the procedure.

1. Put about two gallons of water into the bucket. You’ll probably need more, but it’s easier to add it than to take it away.
2. Pour in the glaze powder in a slow, steady stream if possible. This is hard to do, by the way, and most likely the glaze will all flumph out at once and splash you, but you’ve gotta try.
3. Mix the glaze with the stick first, then, if you have it, with the power drill. If it’s awfully thick, add some water. Let it sit for an hour or two if you can, then mix it again and pour it through a sieve. You’ll need to work the glaze through with a stiff brush. Mix well and re-sieve, several times until the glaze has reached a creamy and smooth consistency.
4. Next day, re-mix the glaze and assess the thickness. For a baseline, you can dip your finger in and out in an unhurried, but business-like motion. If you can still see the lines of your knuckle and fingernail clearly, but the finger is completely coated, your glaze is within the range of proper thickness. If the glaze is too thin, you’ll have to let it sit until it separates, then you can dip water off the top. If it’s too thick, of course, you just add water.

If a glaze has been sitting for several months, it’s usually a good idea to sieve it before using, and all dipping glazes need sieving periodically. To glaze a pot by dipping, you can either keep glaze from sticking to the base by applying wax or just by not dipping the base. Alternatively, you can wipe the glaze off the base on a piece of damp carpet. I use a mix of all three techniques, depending on the piece to be glazed. Here’s the procedure:

1. Any parts of the pot where I don’t want glaze–decorations, lid flanges, etc., I apply wax to. It takes a while for the wax to dry, so be sure to do this several hours in advance of glazing.
2. If the base of the pot is going to be dipped in the glaze, I first dip it into water to keep too much glaze from sticking there.
3. Have a piece of damp carpet available. I put it in a large disposable baking pan to keep it from messing up the table. Using a pair of glaze tongs (available at a ceramic supply outlet), dip your pot sideways into the glaze and remove it promptly, emptying it out of glaze. Place the piece base down onto the carpet, and when the glaze has dried sufficiently, hold the piece by the rim and twist it back and forth until the base of the piece is clean.
4. Alternatively, if it’s possible, you can hold the piece by the base and dip it straight down into the glaze, stopping before you immerse the base. If it’s a cup or bowl that needs the inside glazed, too, you can squirt glaze inside with a turkey baster or pour in with a cup of some sort, swirl to coat, and then pour out.
5. It’s important to keep the glaze as thin as possible near the base of the pot, so it’s not so likely to run and drip during firing, sticking the pot to the kiln shelf.
6. To vary your glaze’s appearance, you can dip the rim of an already glazed pot with a second color. You can drip a second glaze on with a turkey baster or splatter it on with a toothbrush. Be sure you take careful notes so you’ll remember what you did. That way you can repeat a stunning combination or avoid repeating a dud.

Glazes designed for dipping can be painted on, but they don’t flow well, which makes them difficult to work with in this way. They can also be sprayed. I’m not going to go into this here, though. Spraying requires quite a lot of special equipment and so isn’t going to be accessible to very many beginners. I may cover it in a later post.

As with painted glazes, you want the coating to be about the thickness of a credit card, though different glazes require more or less coverage. If your glaze doesn’t show the color, or much of the color you expected, you’ve probably applied it too thinly. Take some water off the glaze, immerse your pot for a longer period of time, or double dip it. If the glaze drips, next time be careful about getting too much glaze close to the base or getting the glaze/glazes on too thick.

Glaze that develops a network of cracks as it dries is too thick. You can heal the cracks by gently rubbing over them with a damp sponge or a damp finger, but if the thickness is heavy near the bottom of the pot, you need to remove some of the glaze there, whether by scraping or washing the area. If this situation is too bad, you may want to wash the pot, let it dry completely, and re-glaze another time.

If the glaze on your pot is too thin, it’s possible your glaze slurry wasn’t well mixed. Glaze slurries need frequent mixing as they settle. Some settle toward the bottom, and others have particles that tend to glob together toward the top of the bucket. Either way, they require frequent stirring. A pot that has been glazed too thinly because of a badly mixed glaze will have soaked up quite a bit of water and will need to sit for a while before you try again. When you do re-dip the pot, just dip the top 3/4 or so, to avoid too thick a glaze layer close to the base.

There’s a lot more than this to know about glazing, but this will get you started. Many books, thick books, have been written on this subject. Just dive in and don’t be afraid to experiment. I’ve tried to point out a few of the speed bumps, but you’ll have both spectacular successes and miserable failures. Don’t give up and you’ll soon have a good understanding of your own particular favorite glazes.

Firing Pottery: Bisque

Firing of pottery can be accomplished in many ways, whether in a campfire, a pit, a wood or oil or gas kiln or, more commonly for hobby and small professional potteries today, by electricity. My expertise is almost entirely in the realm of electrical kiln pottery in the cone 6 or mid-firing range, so that’s what I’ll be talking about.

Firing is another of those deceptively simple parts of making pottery and ceramic art. You take the stuff to a ceramics shop; they fire it for you; you pay the bill–right? Well, maybe you’d like to know just a bit more about the process, especially if you’re thinking about getting your own kiln or if you’re charged with operating one for your school or art center. As mentioned in earlier posts (please read them if you need this info), there are two firings–one for bisque ware and the second for after the glaze has been applied. This post is primarily about bisque firing, though I will mention the glaze kiln occasionally.

Before I talk about firing, do make sure your kiln is adequately vented. Venting of kilns, especially in settings where people live and work, is absolutely essential. It’s not all that expensive, so do it right. An open window and a table fan are not good enough. Ask your supplier of ceramic equipment to help you figure it out. You’re better off not to do pottery at all than to fire an unventilated kiln. In addition, make sure the kiln room isn’t going to get hot enough to trigger your building’s automatic sprinkler system. As you can imagine, this tends to irritate the very administrators who, only a few weeks ago, assured you that no additional measures were necessary. (I haven’t experienced this, but I know someone who has.) A proper ventilating system takes out toxic or irritating fumes, but will not keep your kiln room cool. Both of these factors must be addressed before beginning to fire your kiln.

Though I’ve given you some actual temperatures in my earlier posts, firing isn’t quite that simple. Potters use “pyrometric cones,” which are little cone-shaped pieces of ceramic material that have been calibrated to slump or bend at a certain point in the firing. Here’s a link to a short Wikipedia article on pyrometric cones. If you’re not familiar with the use of cones, I recommend you read it–plus, it’s got good pictures. The slumping point of cones doesn’t correspond with any exact temperature. Many kilns don’t even have thermometers (or more accurately, thermocouples). All they have are devices called “kiln sitters,” which use a mini-cone or a mini pyrometric bar as a prop to keep the circuit that turns the kiln on closed (that is, connected). When the cone bends, the switch falls, opening the circuit and shutting off the kiln.

Just to take a little of the mystery out of it for those of you who’ve never seen one, here’s a photo of a kiln sitter.They’re all more or less similar.

1. At the top left is a dial that sets how many hours you are planning to allow the kiln to run. This is a switch and will turn the kiln off when it winds down to zero. You would typically set this dial to run maybe a half hour longer than you think the firing will take based on your past experience with the kiln.
2. At the top right is a hooking device. It’s a little lever whose weighted tail extends through the wall of the kiln and into the firing chamber. It is propped by a mini-cone or mini-bar of pyrometric material so that the inside end will fall down, raising the outside end up when the cone or bar slumps.
3. At the bottom right, the little squared ladder-shaped thingy is your second switch. It’s hinged at the top. To start the kiln, you swing it up and hook the hook thingy (#2) onto it (with a cone in place inside the kiln). It doesn’t look like it in this picture, but there’s a bar across the end for the hook to hook onto. The silver dot that’s just above it in this photo is a button that you push to start the kiln. It won’t start, though, unless you’ve dialed in some time on #1.

Two factors cause cones to bend, both of which affect the pottery similarly. The first is, of course, temperature. Second is “heat work,” which is effected by a combination of temperature and the duration of the temperature in the ware. Just as you can cook a casserole at 250 degrees or 350 degrees (250 will take longer), you can fire a pot completely though the temperature within the kiln may not have reached the target–it just held longer, causing the heat work to get done, though at a lower temperature. If that all sounds too complicated, all you need to know is that, when the cone bends, the pottery is done (or if it’s not, you need to adjust your kiln sitter or change to a different cone (or change your clay or glaze). For more information on this, I recommend Orton Ceramics, which manufactures most of the pyrometric cones used in the USA.

You should know that a mini-cone or bar designed to is roughly equivalent to a shelf cone of the next higher denomination. In other words, though they’re made of the same stuff, they bend at a cooler temperature than their big brothers because they’re such thin, frail little things.)

More modern kilns are controlled by computer devices that use thermocouples to measure the temperature within the kiln. At the high temperatures within a kiln, normal thermometers can neither give a reading nor survive. Thermocouples aren’t all that accurate, but they’re consistent. There are more accurate ways to measure temperature within a kiln (by analyzing the color of the light, among other things), but they’re unnecessary for home or hobby potters and tend to be pricey.

Even if you have a computer controlled kiln, you should still use cones. Cones are a more relevant way for potters to measure the effects of temperature and time on ceramic ware because cones are made of ceramic material. You’ll need shelf cones–get the self standing ones–they’re worth it. By experience, you’ll learn how far you want your cone to bend over for the type of clay and/or glaze you’re using. When the tip of the cone touches the shelf, it has reached its calibrated “doneness,” but the melting will continue during any “soak” time you’ve programmed into the firing schedule, so you want to start the soak period before this happens. And your particular glaze may actually mature at a lesser or greater degree of cone melting. So, experience and experimentation are necessary.

As I mentioned, bone day ware still has some moisture in it, from the humidity of the air. It may also have moisture from not having dried completely, especially if your pottery has any especially thick parts. I start my bisque kiln by programming it to hold the temperature of 180 degrees Fahrenheit for several hours. If I have monster pots inside, I might hold the temperature for as much as 6-8 hours. This might not be necessary, but there’s a lot of work in those big pots and I don’t like them exploding. If you’re using a kiln sitter, you just can’t fire big, thick pots. If you’ve figured out how to do it, let me know–I’d like to hear. The kiln (even with only one element set to low and the lid propped open a foot) will heat to above the boiling point of water, the water remaining in the thick walls of your pots will flash into steam, and you’ll have a broken pot. Since I live and have my studio at an elevation of about a mile, I keep the pots at 180 degrees rather than 200 degrees. The boiling point of water is lower up here in the clouds.

So, step 1: Place a mini-cone into the kiln sitter. You can adjust firing temperature slightly by sliding the cone to the right or the left. Closer to the small tip, the cone will bend sooner; closer to the large base, it will take longer, resulting in a hotter firing. If you’re using a mini-bar, the adjustment isn’t possible, but your firing results will be more consistent. Unless you have only thin, light pots, I recommend “candling” the kiln before firing it. Prop the kiln lid open about a foot and fire with one element set to low for a day–maybe 8 hours.

If you have a computer controller, place three self-standing shelf cones where you’ll be able to see them through a peep hole. If you’re going for a ^06 firing, you should have an 07, 06, & 05 cone (of these, the 05 is the hottest cone). Place them in a row horizontal to the middle peep hole, at least 6″ away, with no pots behind or in front of them to obscure your line of sight. You can set the kiln to hold at a temp around ten degrees below boiling for several hours–adjust this time depending on how thick your pots are. Go to step two for your next setting.

Step 2: If you “candled” the kiln as I recommended in step one, you might want to simply turn off the kiln when you leave and close the lid. You can start it back up in the morning. When you’re ready to fire, make sure the lid is well-closed and all peephole plugs are in. Turn all elements to low. Fire this way for two hours.

If you have a computer, you will have set the kiln to fire at 200 degrees an hour up to 1100 degrees (this is where chemically combined water is exhausted). Go to step three for your next setting.

Step 3: Turn the elements up to medium and hold there for two hours.

For the computer controller, you will have set the kiln to fire at 300 degrees an hour up to your chosen peak temperature. For bisque firing, this is usually cone 06, or around 1860 degrees Fahrenheit. Go to step four for your next setting.

Step 4: Turn your elements up to high. When the switch falls, you’re done. Make sure you check the kiln to be sure the sitter shuts it off properly–you’ll want to keep records of how long your kiln typically takes to fire. Kiln sitters can get stuck, so this is important. Never fail to check (in a timely manner) that the kiln has shut off. Kiln sitters are prone to occasional failure, and it’s possible that your timer knob could also fail, particularly if the kiln gets hot enough to damage it. If the switch has fallen, the kiln is off, though you might want to disconnect the circuit by switching off the breaker to make extra sure.

Set your computer controlled kiln to hold the peak temperature for 30-60 minutes. This allows impurities (such as organic matter and sulfur), which could cause bubbles in your glaze later, to burn out. Check the kiln to make sure it shuts off after your soaking period, then just let it cool.

If you’ve placed shelf cones where you can see them through a peep hole, you can put on some kiln gloves (or heavy leather gloves), take out the peephole plug and immediately place it securely on the lid. It will be glowing orange. Wearing a good pair of sunglasses, look into the kiln and try to discern the shadows of the cones to see whether any of them have begun to bend. You should have your target cone in the center, and when its tip has touched the shelf, your firing is complete. Don’t forget to replace the plug when you’re done. You lose more heat than you might think doing this, and it’s hard to see the cones, but it does help you to figure out what temperature you should set the controller to fire to. It’s usually way different from the theoretical temperature. If you absolutely can’t see the cones, just try to adjust your kiln’s temp by looking at the cones after the firing. If your target cone is a pile of goo, you can back off the temp maybe 30-40 degrees. It’s a matter for experimentation and trial and error.

Above all, make sure you or some other responsible person can be present when the kiln is reaching its peak temperature. It’s important, despite all the fail-safes built into modern kilns, that you make sure the kiln shuts off as it has been told to do.

Let the kiln cool until the pots and shelves can be handled bare-handed. Any hotter than this and you risk breaking your pottery by taking it out too hot, thus exposing it to thermal shock. (Or simply dropping it because it’s burned your hands even though you were wearing thick leather gloves–yes, I’ve done both of these things.)

For both the kiln sitter and the computer controller, shelf cones are helpful (see step one for the computer kiln). They give you a truer picture of the conditions inside the kiln needed to attain your desired results. Pots that exhibit glaze faults such as pinholes in the glaze may need a longer soak at the peak temperature or a slightly higher bisque firing temperature. Clay should burn off all its gasses during the bisque firing–bubbles in glaze indicate that this hasn’t happened (or that the pots were dusty when the glaze was applied). To soak a kiln with a sitter, you have to prop up the switch, which isn’t recommended. However, if you do it, bring a chair and sit there and watch the switch for a half hour, then un-prop it. Do not, under any circumstances, leave a propped switch for even a few minutes. You will forget about it and melt down your kiln.

Pots that haven’t been bisque fired hot enough may take on too much glaze, causing the glaze to run and stick to the shelf. The solution to this is to either fire the bisque hotter or to thin out the glaze slurry.

There’s certainly more to firing than this, and if you have suggestions or questions, please feel free to contribute. It sounds daunting, and many books have been written on this subject, but don’t get scared off if you’re a novice. You’ll get the hang of it really quite quickly, though you’ll likely never stop learning new things about firing.

God bless and happy potting,

Cindy

Drying Pottery

Drying your newly made pottery pieces may seem like the least of your worries, but it’s not as uncomplicated as it looks. Not terrible, but there are some tips that will help you to get through this stage safely, and I’ll share some of them with you here. If any of you reading have additional insights, please feel free to share. Likewise, if you have questions, please post them. Your questions and insights will make this post more useful to everyone concerned, including me.

It is important not to dry your pieces too quickly, and the more complicated they become, the more slowly you’ll want to dry them. A cheap plastic painter’s drop cloth is your best friend here. Buy one and unroll it bit by bit, cutting off pieces of the width you need. Drape them loosely over the pieces you want to dry slowly. For pieces you’d like to hold at their current state of wetness, it’s good to wrap them in the plastic bags they give you at the grocery store–two or three of them–and then drape them with the plastic drop cloth.

Coil built and puzzled pots in particular need slow drying. Pieces with appendages such as handles or applied decorations also require slow drying, but not so slow as for the coil built pieces. Pots made all in one piece may be dried more quickly, but you should turn them upside down if possible as soon as they’ve hardened up a bit. If they can’t be turned, set them on a piece of drywall (sheetrock, gypsom board, wall board) or plaster to allow their bottoms to dry evenly.

If your pots are cracking as they dry or during bisque firing, they are drying either too quickly or too unevenly. Keep them out of drafts (cover with plastic if necessary) and away from heaters or air conditioners. If you still have problems with cracking, you might need to change your clay body.

Clays go through different stages during drying. Really, they pass along a continuum from soft plastic to bone dry, but there are a few stops along the way, which I’ll describe for you as well as explain what sorts of things might be done to a pot at that stage.

1. Soft plastic: At this stage, the clay will hold its shape, but it is easily altered. You can join pieces, such as handles or knobs, at this stage, but the softness of the clay makes it difficult to do so without deforming the vessel walls. You can alter the vessel walls, stretch the clay, compress the clay–this is the time to set the shape for your pot. It will be more difficult or impossible later. Clay at this stage is sticky, and if you attempt to carve it, you’ll have a bit of a mess, with the pieces you’re trying to carve away sticking to your tool, each other, and the pot itself.
2. Soft leather hard: The clay has begun to firm up, but it’s still a bit sticky and you can still alter the shape of the vessel. If you want to put scallops in the rim of your bowl or plate, this is a good time for that. The clay is firm enough to hold the shapes you’re creating, but you must work gently or you could cause cracks to form. If you have decorative or functional bits you’d like to add to the pot, you can do that now. The clay is still a little too soft to easily add handles, but it’s a perfect time to add little molded pieces for decoration–say pine cones or seashells. Be sure that you don’t trap any air under these appliques, or the expanding air during firing could blow the applique off the pot. If you have any thick parts (more than 1/2″ or so), poke some holes through them with a needle tool to help them dry and avoid later explosions in the kiln. You can heal these holes on the outside of the pot if you like, and just let them have an opening on the inside of the pot. It will be filled by glaze later. If you have any enclosed hollow spots, they’ll need holes poked in (one or two are plenty) to allow expanding heated air to exit. Be careful when you’re poking these holes, as the residual stickiness of the clay may fill them in as you’re removing your needle tool. If you try to carve the clay at this point, you’ll still have it sticking to your tools, though not as bad as before, and it will tend to form jagged, sticky edges on the parts from which it has been cut away.
3. Leather hard: The form of the vessel can’t be altered without cracking the clay. At this point, you can add handles, etc. (Remember our earlier lesson, though–as always, scratch and moisten or add slip before attaching). You can still add decorative bits as described above. This is the optimal time for trimming the bases of wheel-thrown pottery (a process I’ll get into when I start to talk about throwing). This is also the best time to do any carving you’d like to do. Ribbons of clay will fall cleanly away from the pot, making little curls that sometimes still stick to the body of the pot. Leave these fragments. When the pot is dry, you can easily brush them away.
4. Hard leather hard: The pot is just about to start losing it’s dark, wet color. If you carve away a little strip, it won’t hang together as at leather hard, but will fall into crumbles. Still doable, but not as nice as it was at leather hard, and it will dull your tools more. You can still add stuff to your pot if you absolutely must, but it’s more likely to crack off. At the hard leather hard stage, your pot has shrunk about 6.25%. The bits you’re adding on still have that amount to shrink, so you can see where this could cause some pressure. If you have to add stuff at this stage, be sure to moisten, scratch, slip well, and keep the pottery under plastic for a week or so before you allow the drying to complete. You can still trim on the wheel, though it will be more difficult and will dull your tools more.
5. Bone dry: The pottery is room temperature to the touch, not cool. Coolness indicates continued evaporation and an incomplete drying process. It has lightened in color and feels absorbent–like old dried out bones. This pottery is past the stage of working with, unless you break it up and dump it back into the slop bucket and let it dissolve and return to the plastic clay state. You can sand it (wear a NIOSH approved mask), but that’s pretty much it. Bone dry clay in Florida isn’t the same as bone dry clay in South Dakota because the relative humidity in these two places is very different. Clay will always be as moist as the air around it until it’s been fired.

Take care of your bone dry pieces. They’re hard, but very brittle. Don’t hold cups by the handle or lids by the knob, and be careful not to bump delicate appendages. If you do break something, you can attempt to fix it by moistening both surfaces and trying to smooth the two pieces together. Sometimes it works. Better not to break it.

Next I’ll talk about your first firing. In the meantime . . .

God bless and happy potting,

Cindy

The Pottery Process in a Nutshell

People think that making pottery is like baking a pie. It isn’t all that hard to do, but there are some things you need to know. Because the pottery process is so mysterious to so many people, I’m going to lay down the basics.

Here’s the process most conventional, electric-fired stoneware pottery goes through in the United States. I’m not talking about the sort of pottery where liquid clay is poured into a mold–that’s a branch I’m not very familiar with. I’m talking about pottery made from clay in its plastic state.

1. Forming: The pot is formed with any appendages, carving, etc. completed.
2. Drying: this may be done quickly if the clay will tolerate it and the pot is of one-piece construction. If bits have been joined together to make the pot (such as coils) or if bits have been added on (such as handles or knobs or butterflies or what-not), the pot must be dried slowly under plastic for a few days and then moderately, out of the way of heaters and breezes.
3. Bisque or Biscuit Firing: This first firing gets its name from the feel of the wares when they are fired. They have a dry, absorbent surface like hard biscuits. The typical temperature to fire bisque ware is called “cone 06″ and is around 1860 degrees Fahrenheit.
4. Glazing: Glazes may be applied by dipping the pot in a bucket of glaze, by painting glaze on, pouring glaze over the pot, or by spraying.
5. Glaze firing: For cone 6 pottery, the peak temperature of a glaze firing is approximately 2232 degrees Fahrenheit, or “cone 6.”
6. Cooling: Some glazes, particularly non-shiny or matte glazes and glazes with large (macro) crystals, require a slow cooling to reach their best presentation.
7. Finishing: This may include grinding off glaze drips, sanding the bottoms, adding wicker handles, etc.

In the next couple of days, I’ll post articles on each of these steps (except #1, which is pretty much all of my other posts) giving you more exhaustive information.

God bless, and happy potting!

Cindy