Can You Stack Your Greenware in the Kiln?

Most definitely! There are, however, some things you need to be careful of.

If you plan to glaze the pieces, it's best not to overload the kiln, too much. The likelihood of the center pieces not firing as hot as the outer edges, is too high. But if you meerly plan to paint and finish, there is no problem if there are slight temperature differences in your firing.

From my experience, stacking more than 3 plates is taking a huge chance on that bottom plate cracking right in half. When stacking plates, it's best to use small ceramic rods between the layers of plates to insure they don't stick together.

Stacking large platters is risky. I've successfully stacked 2 with rods between. One thing you need to watch for, when firing that large oval platter is sagging of the brim. I usually use pieces of kiln blanket, at least at the ends and midway down the sides, as support.

There's always the temptation to stack mugs, with the bottom mug turned upside down. That works out ok but only if you make sure you have a good thick coat of kiln wash. If not, there's the possibility of the brim of the mug sticking to the shelf, causing a crack or warp. I've stacked them up as high as 4, with no problem.

Large bowls need a little watching after. Turned upside down, if you don't have a good coating of kiln wash, they are liable to stick causing a crack or warp. I have a habit of using the bowls to hold a load of miniature items. The only problem with that, is you need to make sure you pack around the outside also, to prevent warping. If you have several bowls, all the same mold, you can stack them so that the bottom bowl is sitting on its own feet, while the top bowl is matching lip to lip, upside down. If they stick, a little, hold them firmly, after unloading the kiln, and pop your hand directly onto the side, right at the edges of the bowls. They will pop apart.

Very tall vases can be laid down but only if you are firing a huge amount of small items. You can use those smaller items to pack around the vase, making a bed as well as side props out of them.

I used to produce so many miniatures and very small vases and pots, that I loaded the kiln absolutely jammed. I'd stack them about a foot deep before adding another shelf. As long as you watch that your greenware doesn't touch the elements, you should be fine.

When it comes to the bisque firing, I'm a waste not-want not person. I use every square inch of space.

Very large bowls, something like 15" or wider, needs to be propped with other pieces, evenly all the way around, as they will tend to warp.

There's nothing I love more than loading up miniatures in a kiln. I get my money's worth, for sure.

Firing the Large Platter

One of my readers came up with this question and I realized there was something I had forgotten. It's been so long.

It's true that one needs to stilt the green ware of that long, large platter for firing to bisque.

The reason is this. More than half the piece, is bottom. Considering its size, that means something. Your green ware must be able to move and slide or it will break. Because of its weight and the wide span of the bottom (foot) its much easier for the piece to drag hard across the shelf, not giving it enough breathing room for shrinkage.

Add to that, the fact that there is much more trapped air under the piece. Many times, just due to the weight of the center part, pulling it out of the mold will warp the foot just enough to weaken it. For that reason alone, you need to take special care in how it sits on the kiln shelf.

I've stacked as many as 3 of these platters for the bisque firing but if I forgot to stilt the bottom piece and place stones between, I'd say I averaged a good 30% breakage.

I would also advise, laying small posts on their sides, just under the lip to the platter about every 4" just to insure the lip doesn't sag and crack the bottom portion. It may be overly cautious but it sure will be worth the effort.

The glaze firing, of course, is a different matter as the clay has already shrunk.

Finding Clay in the Wild

You ever wish you could just find some of that clay sitting around on the ground? Well, the truth is, sometimes it really is.

I was in the mountains to get wood. My daughter was driving the car while I drove the pickup. I stopped along side the road, where a million other people have pulled off onto this plain dirt area. It was just to stop and see if the kids needed anything before we hit out on the highway.

As I stepped out of the pickup, my foot landed on hard dried mud. As in, previous tracks had become a permanent indention in the mud while it was wet. Hmmmmm.....only clay does that.
I followed the deep red clay up the side of a small hill. Never did find out where it was originating from but did I ever find a solid patch of it, where ATV's had ground it to almost a powder.

Here's my scientific, never fail test. I took a little of the dust in my hand and spit on it. Sure enough, it was just as slimy and smooth as it could be. If it had been grainy, it would not be clay.
How's that for a test? ha

I came back later, with a 5 gallon bucket and filled it up. Then I took it home and poured water over it until it was completely covered. After a couple days of soaking, I took another bucket and an old piece of screening, I stretched the screening over the bucket and secured it with a mold strap to hold it in place.

Then I just sat there pulling out hand fulls of the wet clay. I dumped it on the screening and worked it through, leaving the sticks and small stones on top. Those, of course, I dispensed with and just kept the fine clay.

After it had dried enough for me to handle it, I formed a small bowl and covered it to dry slowly, to see if it would crack. This particular clay, I had found, was superb just the way it was.

In the past, I've found pockets of clay in the river bed. Usually, in December when the rivers are at their lowest. Some of that clay is just too pure and has to be mixed with fine sand, to keep it from cracking.

Oh, and by the way, I fired that clay I had found and it fired beautifully at 04. The only problem is, when you want to glaze. There's no possible way to already know the shrinkage rate of the clay without some testing.

Looking for and finding clay can be fun and it sure is a cheap way to get your hands on clay.

Ceramic Finishing:Those seams in poured ceramics

After reading an explanation of clay and an understanding of platelets, you can better understand the appearance of side seams in your poured ceramic pieces.


The older the mold, the more accentuated will be the seam. The reason for the seam appearing at all, is explained by 'platelets'. Clay slip doesn't know where it is, it just knows it consists of platelets which lies one on top of the other. Everything is fine, in a mold, as long as the platelets have a flat flowing surface to lie down on. The platelets don't know to skip over a tiny gap in it's surface, so it follows around the tiny edge of the seam where the two sides of the mold are touching.


So you can imagine the platelets bending around that corner and into the tiniest crack. This means that the clay you're seeing that is formed by a seam, is the edges of the platelets (not the flat side of them). That's why it seems darker right at that spot.


The only way to eliminate that darkened seam and actually flatten it out so that it doesn't show at all, is the flatten it while the greenware is still very wet. Preferably, as soon as it comes out of the mold.

A view of what the platelets are doing right at the mold seam. Since you're seeing the edge of the platelets instead of the flat side (as usual), it appears darker in color.

Clay: What Is It

Much easier to draw than to spell it out with only words.

Clay is not like sand or soil in that sand or soil consists of granules. Clay consists of platelets.

Much like this

When the clay is very very wet, the platelets are separated like in this first drawing.



As the clay dries, water is holding the platelets apart, less and less and the platelets began to come together like in this second drawing.

The closer to dry, the clay gets, the more it looks like this

The platelets are floating apart when there is a lot of water, as in when the clay is wet enough (soft enough) to be formed. As it dries, the platelets float closer and closer together. When completely dry, the platelets are attached to each other.

Ideally, the platelets are coming together with no air pockets trapped inside because as the platelets close in on one another, they actually can cause a barricade the air cannot escape. When this happens, the results are a disaster.

In the kiln, as the clay warms up, any air trapped begins to swell. Remember? Heat expands and cold contracts. As the air expands from the heat, it becomes bigger than the space it is trapped in and something has to give. Guess what. The clay must give. Cracks and explosion in the kiln.

This is the reason you have to be oh so careful about letting air get trapped inside the piece you're working on.

When throwing on the wheel, air gets worked to the surface simply by the centrifugal force and the constant applied pressure to the sides.

When hand building, it's too easy to let an air pocket get past you. You have to remain sensitive to the feel of the clay, as you work, and notice odd slipping under your fingers. That's an air pocket.

I hope this has been interesting and educational. It's much appreciated when you comment, to let the writer know her efforts are helping.

Judy

Ceramics

When you think 'ceramics', what is it that comes to mind?
A cup or vase? Or do you immediately relate to your own experiences with clay?

Ceramics, to me, means just about anything you can make out of clay. I've hand built using clay I've found, I've poured clay slip into molds, I've even dabbled on the wheel.

Sometimes I think people are confused about the differences in the terms "Ceramics" versus "Pottery" and the plain fact is, there is no difference.

Well, I mean there is no difference basically in the materials used but of course, there are differences in the formula and body of clay one is using, at the time.

One can pretty much take the over all subject of ceramics and break it down into 3 categories: clay slip, pottery and hand building.

Hand building and the term 'pottery' (or thrown) uses pretty much the same combinations of clays while clay slip is formulated to make the clay a pourable substance like milk and is poured into molds.

Within each category, one can also break it down further as there are so many different types of clay. There is earthenware, stoneware and porcelain.

Earthenware (the most commonly used by throwers) is basically medium in coarseness and texture. Usually a misture of clays from different parts of the world.

Stoneware is a sturdier clay, rough in texture and formulated with the higher firing clays along with a grit of some sort.

Porcelain is a whole other subject, in that true porcelain clay is only found in China while the other countries have (through the years) perfected blends that come the closest in transparency and texture to pure porcelain. Most of what you see on the market today, is this finely tuned formula.

Porcelain is used for fine works such as dinnerware and dolls faces.

Since porcelain is what I refer to as 'the driest' of clays, it's the hardest to work with as it's less pliable than the others.

Today, you can make a clay slip out of just about any variety of clays including porcelain, the same with ball clays which are used for forming.

What is clay slip?

Clay slip is clay with additives to make it pourable.

To explain how slip forms into greenware which is then fired to create bisque:the plaster used to make the ceramic molds, has what is called 'channels'.

The channels are formed as the plaster is setting up. It is these channels that make slip casting possible.When the slip is poured into a mold, the moisture against the plaster begins to draw completely through the mold, via these 'channels'.

Since this action is only affecting the slip that lies against the mold, a thick shell of clay begins to form and it grows thicker as long as the slip is in the mold. When that shell is thick enough, the pourer then dumps out the slip, stopping the shell from getting wider (thicker).

As is the nature of clay, it shrinks as it dries. The pourer will wait until the shell (which is the future greenware) has drawn away from the inside surface of the mold (as it shrinks), then open the mold and allow the greenware to harden just enough to be handled.

Then the greenware can be lifted out, popped out,dumped out and set on a shelf to dry.Not much mystery there.

http://judysbookshop.com/pouring-for-ceramics.htm

Poured Ceramics: Simple Tricks

There's always more articles on this subject at http://judysbookshop.com/ceramic.htm

If you've been dabbling in poured ceramics for any time at all, it's time to learn some new tricks.

Despite what you've been told, you don't have to wait until the greenware is dry before cleaning it. In fact, it's much cleaner work if you clean it while it's still wet.

You can trim off those seams and then flatten them out, with the side of your cleaning tool. This way seams don't show at all, in the finished piece. Using a wet sponge, at this stage is also a cleaner job, as it doesn't take much water at all to smooth out the rough spots.

You really need to have experienced handling wet greenware before attempting a wet cleaning job, as you can hold it too tight and collapse the piece. If it's strong enough to just sit on a small board, it's best to leave the piece in the standing position, so that you don't handle it too much. Miniatures, you can hold in your hand while cleaning. It's really no big deal.

Careful not to use a sponge too dry though, as this can pack down the clay, causing a slick spot. If you plan to use glaze or underglaze, that's important but if you plan to simply paint on bisque, it makes no difference at all.

You can also add and subtract clay bits to change the design. As long as it's still wet, you can add a little slip, slide too pieces together, sponge off the excess and you've made an attachment.
'
You can carve out designs like in the side of a pot. You can attach the carved out pieces to the side of the pot using slip like a glue. As long as everything is still wet and has not yet shrunk.

You can play with the greenware, all the way up to the leather hard stage.

http://judysbookshop.com/ceramic.htm

Novice, Confusion, Misinformation?

Now that I know what I know, I realize how odd it can be to have first hand knowledge of clay and yet be in the dark about what all those molds and designs are all about.

That did happen to me. I grew up finding my own clay and creating things like little pueblo houses, bowls and vases. The only problem was, as a child I had no idea there were other people playing with clay.

I later learned from the Indian ladies, how to build pots for firing but again, having no access to a kiln or any other firing facility, I never saw one of my pieces fired.
'
I was 30 years old, the first time I ventured into a 'ceramic shop', one of those places with all sorts of greenware on the shelf. In my curiosity, I reached out just to touch the side of a greenware piece only to be reprimanded by the owner. She didn't offer assistance, only hollered, "Don't touch! They're very fragile. You'll break it!" I left.

It wasn't until I was around 40, I again ventured into one of 'those' shops. This is where my education began, in the poured ceramics world.

It was another 10 years before I got into it seriously, as life neccessitated I find a way to make a living without withholding taxes, which meant no employer-no above ground visibility, as I needed to hide from a very strange ex-husband.

I was forced to learn all I could, as fast as I could and find a way to make it work.

In my ventures, I was not only surprised by the fact that basically this greenware stuff was the same as what I used to dig out of the river, I also discovered the many wives tales being taught to the average student.

While the potters and poured ceramic artists, each deemed themselves superior to the other, I stood with a foot in both worlds and saw very little difference. Both worked in clay. The only significant difference I could see was the fact that poured ceramics was formed by a commercially produced mold, while the potter formed from memory and talent. I like both. Crossing the lines between the two, brought me into yet a whole other world in clay, which is pretty much just my world. I don't see others playing in both sand boxes.

I'll be back to ramble some more.

Ceramics: Mistakes

You picked up a wet greenware pot, too soon and now it has finger marks on the sides. Um...big deal.....so what?

You've just created a unique pot.Push it in some more :) Bend the neck around some. Make something artistic, out of it.

Oops tore the neck? Tear it some more! Curl the torn parts back toward the pot, twist it around....hey, you could even get rid of that part, all together.

So it isn't perfect, the way the mold should have formed it....all that. Big deal! Now it's a one of a kind.If you're using an artistic glaze, it will just actentuate the dents and mishaps. If you're painting on a design, you can use the dents and mishaps to help form a picture or shape.It's all cool.

Ceramics: Patching

I've tried all the commercial patch materials for poured ceramics and still keep going back to the old handy recipe. Take a little slip in a cup, add about the same amount of vinegar and watch it boil up. After it seems to have stopped foaming, add some clear glaze and mix together.

It's a great patch. Dampen the edges of a break, with vinegar and let it boil for a second then you can add your patch material and press together.

At this point, your mend is VERY fragile. If you can manage to get it to the kiln without it falling apart again, you have about a 90% chance of it holding.

Free Gift

I've uploaded a free gift to my website. It's 2 gift cards, I think you will like. One is New Bride which consists of 6 pages when folded, the other is New Mother which consists of one card stock page folded.the New Mother contains all sorts of well wishes, the same with the Bride but with some recipes and hints and helps.
There are instructions for print out, on the same page as the links to the files. You just right click the file you want and 'save target as' to download.http://judysbookshop.com/giftcards.htm
Enjoy,judy

Creating in Ceramics

I used to run into this all the time and now I see more hogwash on the internet. Where do people get these crazy ideas about ceramics.

I've heard things like 'it takes a lot of big equipment', which is just plain stupid talk, and 'very carefully', which just makes people afraid to touch clay.

I hate the idea that folks are being led down such paths when in actuality, working in ceramics (in any form) is simple, fun and fulfilling.

First, let me tell you that you can create ceramics on your own lap, if you had to.

Did you ever play with clay as a child? You remember what it felt like? I mean, any kind of clay even the oily stuff.

Earthenware and stoneware clays are the same thing. Well, by that I mean, pliable/bendable. It doesn't matter if it's in ball clay form or clay slip. Even the slip can thicken enough for you to hand form it.

What I'm saying is, clay slip is not a mystery. It's just clay that is thin like cream, with additives in it to make it pour like fluid instead of just blobbing in clumps. In this form, clay can be poured into a mold, left to thicken a shell against the inside of the mold and then the excess poured out. Now doesn't that sound simple?

It actually is a simple process that folks have a tendency to make sound as though you have to have some sort of science degree to master it. Not!

I'd love for you to drop by my website and read more about it.http://judysbookshop.com/pouring.html

Other ceramics blogs http://pour-ceramics.blogspot.com
http://clayslip.blogspot.com