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What is ceramics? The term ceramics is usually referring to an inorganic, nonmetallic material consisting of mostly silica and alumina. It is a brittle, crystalline structure, most of the time. A ceramic is distinct from a clay in that the organic portions are refined out of the mixture. You may find clay to create ceramics from riverbeds in the form of decomposed rock. When it is in the form of clay it is most often a mixture silica, alumina with water. The structure of clay takes the form of thin flat plates surrounded by water. Think of those plates as a deck of cards. If you had a wet deck of cards, the flat cards would stick together, but also be able to slip and slide past one another quite easily. Building with Clay: When shaping clay usually begins by wedging clay. It is a similar motion to kneading dough. There are a couple kinds of wedging. Rams head and spiral wedging. The goal is to align the plates in one orderly direction and to push out any bubbles of air trapped in the clay. http://www.youtube.com/watch?v=vj6Kd8RSmVY There are many ways of building with clay. Handbuilding Pinch Pots- This is how we teach kids to play with and understand clay. (I sometimes teach it to adults as well.) The idea is to take a small ball of clay and press your fingers or thumbs into it to create an indentation in the center of the ball. You then pinch the clay until you have a small bowl with walls of a uniform thickness, spraying with a water bottle as needed so that there is a uniform moisture content throughout. Early clay vessels were made this way.  Coil Building: This is the process of creating long snakes of clay. You can roll them or use an extruder to press them out of a tube. It is structurally preferable to roll them, as compressed clay tends to be a stronger structure. The process of using an extruder is much quicker. Most clay vessels were made this way until the invention of the wheel.  Slab Building: You can create a slab by throwing it. You can begin a block of clay and stretch it out by lifting and and throwing the clay on the table with a pulling motion. http://www.ehow.com/video_2377003_hand-making-clay-slab.html You might also create a slab by using a rolling pin and rolling the clay out like you would cookie dough. There are slab rollers made specifically for making flat even slabs of clay. When building with slabs it is common to lay down grog (fired bits of clay) on newspaper and sandwich the clay between the newspaper and pieces of plywood. You then use books or bricks to keep pressure on the clay as it dries. This way the slab dries flat and does not warp. You can build with the slabs like bricks or a like you would a gingerbread house. Instead of using mortar or frosting, you use clay slip. Clay slip is dried clay mixed with water until it has the consistency of cream cheese. To stick the clay together you use a needle tool to scratch and score the surface of the slab and press the two pieces together with slip in between.  Wheel Throwing Is a quick way to build with clay. Centering: You begin by compressing a mound of clay in the center of the wheel. Coning or pushing the clay up and pressing it back down until the clay is a dense cylinder in the center of the wheel.  Opening: Once the clay is centered you open the center, using your thumbs or finger to create a channel in the middle of the clay.  Pulling: You can then pull the walls of the clay up until they are an even thickness suitable for the shape you want to make. Shaping and Trimming: At this point you can create whatever shape you would like, a cup, a bowl a vase. . .  Once the shape is acceptable, you then allow the clay to dry. When it is considered to be at a leather hard stage you place the clay upside down on the wheel and trim the outside and bottom lip of the vessel using ribbon tools.  Mold Making and Casting Casting is way to make many replicas of a product very quickly. Plaster Molds- Most commonly you make a mold out of plaster by pouring plaster, shaping it with tools or building it up layer by layer. Commonly you create an object out of clay and then create a negative of the object out of plaster.  Slip Casting - Once you create a plaster negative you pour clay slip into the mold. Once the slip becomes leather hard and pulls away from the plaster, then you can open the mold remove the clay.  Firing There are many kinds of clay bodies, and there are different range of temperatures at which they fire. A low fire clay body is often between cone 09 and 02, between 1700 and 2100 degrees F. Mid range clays fire between cone 1 and 6, between 2100 and 2250. High fire is cone 7 to 10, and fires between 2260 and 2400 degrees F To fire you wait until the clay is bone dry to the touch. For the first 200 degrees most the initial moisture trapped between the clay particles is released from the clay. If the clay temperature is increased too quickly trapped moisture may cause the clay to burst instead of venting through the clay pores. (Clay is recommended to be hollow and any pockets of air need a hole to vent through for this reason.) Between 200 and 950 degrees and water that is chemically bonded to the clay body is fired out. Most organic and inorganic inclusions in the clay body are also burned out. At around 1000 degrees quartz inversion occurs. The silica becomes rearranged in a different order. There is a temporary increase in volume that occurs at this stage.It is important that this stage occurs slowly to prevent breakage. Sometimes clay is not fired to the point of vitrification. Vitrification temperatures vary between 1250 to 1800 degrees. At this point the particles fuse into a hard, glass-like matrix. If clay is fired too high, it then can melt or deform. I'm not even going to touch finishes. Glazes, raku firings, terra sigilata, there is a whole world of them out there. And I don't know enough about them. That should get the ball rolling. Feel free to add your knowledge. Show me your ceramics and I'll show you mine.
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Mar 16, 2014 02:02
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So that is generally what most ceramicists think of as ceramics and clay. However in researching ways to toughen clay, I've delved into a world of ceramic composite materials that defy a lot of the definitions that I have been taught. For instance, I had always believed that ceramic was a silica based material, but for many industrial applications the ceramics used are often zirconia based or alumina based with no silica. Zirconium and aluminium are metals, but their oxides are considered to be ceramic. So I thought ceramic was any inorganic, non-metallic material with a crystalline structure that behaved in a certain way. (Brittle, insulating. . . etc.) Then I listen to this podcast : http://www.materialstoday.com/electronic-properties/podcasts/ceramic-paper/ So this paper is made of hydrogen and vanadium oxide threads, it is flexible, translucent and electrically conductive. I have also heard of ceramics without a crystalline structure, and glass ceramics, so to be honest I really don’t actually know what a ceramic is. The ceramic industry has made great strides in toughing by creating ceramic composites. There is a whole world of structural ceramics and architectural ceramics that has hardly been touched by ceramics artists and hobbyists. I can hardly find any information about it, but I am really interested in finding other ceramicists who have knowledge and interest in this sort of thing.
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Mar 16, 2014 02:04
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I'm glad to see a ceramics thread.... I saw a definition of ceramics the other day that was as broad as "anything not organic or metal." I'll see if I can track down the quote. All of the glazes I use are ones that I mix myself, but I don't know enough about the science. Here's the very basic concept glaze is composed of at least three types of substances: a glass-former, alumina, and flux. The glass-former (usually silica) melts and becomes the glaze, the alumina (usually in some form of clay) keeps the glass from running too far, and the flux helps everything melt together at the appropriate temperature. There's a really brief rundown of the chemistry involved here: http://wikiclay.com/wiki/chemistry-short-primer-ceramic-artists When I've got more time, I'll talk a bit about the alkaline glazes that I mix up and use. For now, here's a pic of one of my more recent face jugs:  There are a few other ceramics goons: madlilnerd knows a lot about moldmaking (among other things), and HollisBrown co-runs the PA Mug Co (and has an SA Mart thread selling his mugs).
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Mar 17, 2014 11:20
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Thanks for adding. Glazing is something I really need to learn more about I need to upgrade my account so I can PM people. I should stalk down some ceramics people and invite them to contribute. Post your jugs with faces. I actually teach figurative sculpture. For a long time I was doing lifesize figurative ceramics.   I got sick of large people sitting around occupying space in my apartment, unlikely to ever get sold. So I started making stuff like this instead.  I actually really want to get into architectural ceramics. Door surrounds, and fireplace surrounds, kitchens and bathrooms. Stuff like that. But I have had trouble with the brittle nature of ceramics when making my figures. This is why I am interested in the current technology behind toughening ceramics.
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Mar 18, 2014 05:47
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Whoa, these are cool pictures of stuff, post more maybe? Uh, except Sandwich I am not sure we need to see all the goatse mugs. If you know what I mean.
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Mar 21, 2014 05:59
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Hello, thread. SA user Walking Dad and I are amateur ceramic artists. I took several ceramics classes in high school and college and Walking Dad has some experience from college. My favorite class was an entire semester of raku where we made whatever we wanted and experimented with making our own glazes and firing our stuff ourselves, I would love to do it again. Last year we decided to start dabbling in ceramics again, and last summer we harvested our own clay from a river and experimented with purifying it as much as possible. We ended up with some really nice clay and made a few pots that have yet to be fired. We've got a tiny electric kiln in our basement that we've never used. Honestly I'm a bit afraid because it was free and it's not in perfect condition. There's still a bunch of clay left over from last year and we were planning on harvesting more this summer. The city we live in is pretty arty and we've been meaning to take some classes but they're so expensive. We live near an art studio and were planning on trying to get involved with that this summer and seeing if we can get wheel/kiln time. Hopefully we'll end up with some cool stuff this year.  This is what we started with.  This is the clay we ended up with. Nothing I've made is as cool as life sized ceramic people or face jugs.
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Apr 22, 2014 21:31
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Koivunen posted:
I am awful, as I have not kept up with my own thread. That is really cool that you make your own clay. Do you have any idea what it is in the clay. (iron oxide, silica, etc.) How do you know what temperature to fire to? Raku is my favorite firing process. I will be at Maker Faire this weekend doing raku. I will be sure to take some pictures and post the process. Ceramics classes can be expensive but luckily materials are quite cheap. In my experience, volunteering/interning is usually a good bargain. I find that clay is something that you can learn from books, hands on experience, and experimentation. I don't think it requires a lot of education. Although glazing and wheel throwing can take a life time to become really good at. Let me know if you have any questions about processes. I will answer as best as I can.
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May 17, 2014 01:30
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In highschool I took a "sculpture" class, but unfortunately the only type of stuff we really worked with was plaster (the rest of the class was wood and other mixed media). I'm from deep in the Appalachian mountains of North Carolina, so my whole life I've been surrounded by the sort of culture that produces folk-artsy jugs like the awesome face-jug posted earlier by Empty Sandwich, and I've always wanted to learn to do my own pottery but have just never had the funds or the time. So... that leads to the question: Where would someone even start? My background is in illustration, photography, design.. I'm no stranger to art and have an office closet full of numerous supplies. I've used Sculpey and, as before mentioned, plaster, but that was over 10 years ago. I don't really have access to classes unless I'm willing to drive 1.5 hours and two counties over. What's the best sort of "beginner" clay? I apologize if these questions are stupid, but as you can probably tell I know so very little about this.
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May 24, 2014 21:36
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That drat Satyr posted:In highschool I took a "sculpture" class, but unfortunately the only type of stuff we really worked with was plaster (the rest of the class was wood and other mixed media). I'm from deep in the Appalachian mountains of North Carolina, so my whole life I've been surrounded by the sort of culture that produces folk-artsy jugs like the awesome face-jug posted earlier by Empty Sandwich, and I've always wanted to learn to do my own pottery but have just never had the funds or the time. Your problem in getting started is not going to be classes, it is going to be resources. It's not going to be easy or especially cheap to buy and fire clay where you are. Good news is, clay is cheap. Bad news, you are going to have to order at least 50lbs, so shipping will be expensive. Laguna clay has distributors all over the US and is probably the most widely used brand, so I'd start there. Edit: As far as "beginner" clay goes, almost any clay is pretty easy to use. That said, you probably want a clay that has a little grog but not too much to start. Grog is fired bits of clay added to strengthen the finished product. Theoretically the more grog, the tougher the finished product. Porcelain has no grog, and is like working with cream cheese. Very nice stuff, but best suited for casting and wheel throwing. High fire stoneware tends to have lots of grog and is well suited for very large hand built pieces. But to be honest you could definitely make a larger hand built porcelain sculpture or throw a tea cup out of stoneware. Many new classes use Soldate 60 or B-Mix w/grog. You could start there. But everyone has their own favorites and it's good try out a few and see what you like about them. As far as firing, you have two options. You can buy a very expensive electric kiln, which often means wiring your house for 220V power. (Some test kilns use 110) Your second option would be to make your own propane or wood firing kiln. I have no experience with this. A cursory search would suggest that there are lots of resources online to do this. I have a feeling that firing these kilns will take some time and effort. You will also need to get fire bricks or another form of refractory lining sent to you. The majority of the kiln plans you will find online are raku kilns. This will not work for the original bisque firing. The kiln needs to be brought up very slowly to a temperature around 2000. Raku kilns are brought to a lower temperature over the period of an hour or so. If you are committed to starting ceramics, I would love to see what you come up with for the firing process. Not many ceramicists build there own kilns. But considering most blacksmiths build their own forges, and those who cast metal often create their own furnaces, I don't think it is impossible for a DIY hobbyist. Follow up with me if you find another solution. Or if you get some clay to play with. I'd be happy to give you some hand building advice. ArtistCeleste fucked around with this message at 22:07 on May 24, 2014 |
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May 24, 2014 22:02
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This thread is perfectly timed! I have a ceramics question. I'm building a lab stirrer with a hotplate. Basically it's a strong magnet on a spinning motor under a hot plate that spins a bar inside of a glass of liquid. I've got basically everything done except for the hotplate surface. I have a cartridge heater for heating (heats about 0-400F) and I had originally placed it in an aluminum plate, but it turns out aluminum has something called "paramagnetism" that interferes with the spinning magnet and slows it down substantially. So I was thinking about how to proceed and thought about a ceramic surface instead. Is there a recommended medium to use for high temp applications? I can't imagine ever taking it to 400F but who knows. Good heat transfer would also be a huge plus Also, is there a type of place I can search for to get access to a kiln?
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May 25, 2014 00:27
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ArtistCeleste posted:But considering most blacksmiths build their own forges, and those who cast metal often create their own furnaces, I don't think it is impossible for a DIY hobbyist. Incidentally, my husband does blacksmithing, and has a small forge and tons of Portland cement or whatever those heat insulating bricks are called. We incidentally found a small crucible and at some point I really want to play with metal casting as well, but... would it be possible to fire a pot in a forge? It's coal powered and has an electric fan... and honestly that's about all I can really tell you about it.
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May 25, 2014 02:19
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granpa yum posted:So I was thinking about how to proceed and thought about a ceramic surface instead. Is there a recommended medium to use for high temp applications? I can't imagine ever taking it to 400F but who knows. Good heat transfer would also be a huge plus I will start by saying that this is far from my area of expertise, although it is precisely the kind of conversations I would like to see about ceramics. Ceramic is a great insulator and is often used for purposes that require resistance to heat. That said rapid fluctuations in temperature can cause them to break. In terms of objects created from clay, I would think a low fired earthenware may be able to withstand changes in temperature well. Low-fired earthenware (fired below the point of vitrification) is used in raku because it is more likely to withstand the expansion and contraction associated with the rapid temperature change of the raku. 400F is not a very high temperature considering that 2000 degree bronze is poured into molds made of ceramic slurry and silica. These shells are ceramic but not made from clay. Engine blocks, tiles on the space shuttle, forges, kilns and many other things use ceramic materials not created from clay fired in a kiln. I would search for ceramic refractory materials. You could possibly create a mold and use castable refractory to create the object you are looking for. As far as a kiln, if you have any pottery studios near you most will fire outside objects for a fee. That drat Satyr posted:Incidentally, my husband does blacksmithing, and has a small forge and tons of Portland cement or whatever those heat insulating bricks are called. We incidentally found a small crucible and at some point I really want to play with metal casting as well, but... would it be possible to fire a pot in a forge? It's coal powered and has an electric fan... and honestly that's about all I can really tell you about it. Awesome, tell your husband to post in the blacksmithing thread. I have never heard of a coal fired ceramic kiln, I don't know if one would work. Unfortunately you can not fire ceramic in a forge. Coal gets very hot very quickly and the heat is relatively isolated. You need to be able to carefully control the kiln temperature and evenly disperse the heat throughout. Typically you would bring the heat up to 200 for a few hours, then 500, then 700. . . carefully controlling the heat and the speed over 24 to 36 hours. Wood fired kilns are often fired for days. When heated ceramic contracts significantly and may be 10% smaller after firing. You want this contraction to occur evenly throughout the piece that you are firing. Because of this change, ceramics often break during the firing process. Any concentrated heat would increase the risk of breakage. Try poking around ceramicartsdaily.org for kiln designs. They also have quite a lot of resources about the firing process.
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May 25, 2014 03:09
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ArtistCeleste posted:Awesome, tell your husband to post in the blacksmithing thread. He does! He's uh... I think his name is Kasan on here? Something like that. Thanks for all the awesome info. Everything you've said just makes me want to do this even more. I'll definitely check out the site there. Thank you!
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May 25, 2014 18:45
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ArtistCeleste posted:I am awful, as I have not kept up with my own thread. That is really cool that you make your own clay. Do you have any idea what it is in the clay. (iron oxide, silica, etc.) How do you know what temperature to fire to? No idea. It's clay from the Nemadji river and figuring out the cone will be an experiment but I'm guessing it might be somewhere in the 02-07 range. We have a couple original molds from Nemadji pottery so we were planning on making a bunch of trial pots that won't be a huge loss if they don't turn out. Did you take any pictures? Here are some from my raku class in 2007.  Badass kiln.  Poof!  I didn't get a very good seal on this one and it reduced super hard. I did some horsehair raku but I don't have any pictures of the final products. Will definitely post progress if we get around to doing any firing this summer.
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May 29, 2014 00:53
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Great shots! I spent all my time in a different department and didn't work in the ceramics department until after the rakus were over. We are going to do more this summer though. I will make an effort to get some images.
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May 30, 2014 07:28
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