Handbuilding with Clay: Dish

1. Dish intro: For this demo, I'll be showing you how to make a dish using the slab and hump mold method. We'll cover tools. I'll show you how to roll out a slab. I'll discuss molds and how to use them effectively. We'll cover the process of tidying up the piece at leather Hard. And I would say this process is definitely beginner friendly. Hi. My name is Kelly. I'm an artist and educator based in NYC. I've been teaching ceramics in community and university settings for about ten years. I hope that there's something in this demo that will provide something new for year clay practice. Enjoy. 2. Tools and supplies: Our class project is to make a dish using the slab and slump mold method. To get the most out of this class, follow along with the demonstration at whatever pace feels right for you. Once you've finished your dish, take a picture of it and upload it to the project gallery for feedback from me and fellow students. To do this, go to the Projects and Resources tab and click on Submit a Project. The tools and supplies seal need include a banding wheel, a Biscare mold, or possibly a wooden mold, a feteling knife, a metal rib, a needle tool, a red rubber rib, a rolling device, a ruler, a sponge, water, and wooden boards. 3. Making a slab: Hi there. We are about to begin by rolling out a slab. I got a piece of clay here. Before I roll out the slab, I first want to achieve one of the dimensions for the slab that I need for the piece. I'm going to start squeezing the clay a bit so that this dimension here is already established. Let's say you know that you need a slab that's 10 " wide in one direction. You can achieve that 10 " before you even roll the slab. The only question mark that you'll still have is, do you have enough material that when you roll it, it will achieve the dimension that you want the other way. That sometimes takes a little bit of practice to develop an intuition for it. But usually if you err on the side of starting with a little more clay than you think you need, you're not going to run into a situation where your slab is too small? All right. So for this, I'm going to be using this wooden bowl for the hump mold. And what I'm going to do is roll a slab that, you know, looks like it should be able to cover about the space that I would need for like a low dish or plate. And this, to me, looks great. I don't have to measure it. So, you know, I got the ruler here just as an example, if you needed something to be precise, but in this case, I don't really need to measure because eyeballing it is good enough. All right. So I'm going to start off by flattening this piece of clay a little bit. And that will make starting the rolling process at easier. And making the sides kind of straight sometimes helps them to stay connected to the rollers. Rollers go on the sides, and you want them to be touching the clay on both sides, and now I'll start rolling. Okay. Looks good. I'm going to go ahead now and smooth out the surface with my metal rib gliding the curved edge as I press into the tool so that it's bending and compressing and then making a sweeping motion across. If you're rolling a slab like this and then you're noticing upon compressing the surface to blend it and make it smooth. You notice that there's a bunch of air bubbles. Usually, that means that possibly when you were prepping the clay, you got air bubbles in it by trapping air by folding the clay. It is helpful when making slabs to start by wiring off a chunk of clay from your block as one solid piece that you have to do minimal folding in order to get into the shape that you need. I'm going to flip this over so that I can smooth out the other side as well. 4. Drying process: Okay. All right. Because I'm going to be using this wooden bowl as my hump mold. Usually just by looking at what you have here, the size, the shape, you can usually tell without having to do any measuring whether or not it's going to work. If you're confused or you're not sure, you could always get your ruler, do some measuring and then determine. What I'm going to do here is first, I'm not going to worry about the edge here because that will be cut off after it's on the mold. First, I just want to make sure that the slab is not stuck to the board. That's really important that it's kind of loosely placed on the board. In fact, if you had a layer of canvas you wanted to put between the clay and the wooden board, that couldn't be a good step in making sure that it's not stuck, but I don't think we really need to in this case. I am going to place my mold here on the top, and I'm going to try to get it as centered as possible, just by I looking at it. Then I'm going to put my hand underneath the board and the other hand inside and flip, removing the board, making sure the clay comes off easily. Then I'm going to start pressing the slab down so that it adheres to the form. Now, this style of mold is called a hump mold. A hump mold will always be taking on the form of the convex aspect of the mold. Most well, not most molds, but some molds will be able to be used as a slump mold or a hump mold like this wooden bowl. You can use it on the inside or the outside. The way that you want to think about using these different styles of molds, it's pretty significant the differences. One thing about the hump mold is that it's easier to get the clay to adhere to the form. It's more difficult usually to get it on the inside. But the challenging thing about the hump mold, which is what we're doing here is to make sure that you remove the piece from the mold before it starts to dry too much. The reason for that is as the clay is drying, it's shrinking. When things are shrinking, if there's something obstructing, that gentle movement, that's how we'll get a crack. So if you set your clay on here, you make the shape of your dish or your bowl, whatever it is you're making, and then you just leave it and you wait for it to dry out. If it gets too dry, you might have a crack coming down the side because it wasn't able to shrink freely. So what I would recommend doing is think about using the hump mold as a technique that's used for getting the piece to be the shape you want, but you want to feel like you're able to take it off while the clay still has a little bit of give to it. And that can be frustrating if you're wanting it to be perfectly straight, and it's a really ambitious size, or maybe if you're working with a really thin slab. So yeah, we'll keep talking about that a bit more. The next thing I want to do is shave off the amount of clay here that I don't want for the finished piece. And I just realize I need my bending wheel. Be right back. I got my bending wheel. Now I can very easily make a nice line around the rim to decipher where that rim should be. What I'm going to do is first look at the edge of the clay all the way around and find the part where it's the shortest, where it's not coming down as far, and I'm going to hold my knife. You could also do this with a needle tool. Doesn't really matter which one. Hold some tool here at that spot. Hold your hands steady. So I'm not going to move my hand. I'm going to move the wheel. So my tool more or less stays in the same spot, and it creates a line going all the way around. Now, usually, this is not a perfect technique. There's definitely a lot of room for error if your hand is moving about you realizing it, or if this isn't perfectly centered and it's moving while you turn the bending wheel. That's why it's helpful to position this right in the middle, right? So I might do this a couple times. And the faster you go with the wheel, the more precise it'll be. Because the longer it takes to go around, the more chance it is that your hand will have moved slightly without you realizing. Okay. At this point, I'm going to look at my lines here, see if there's any outliers that are probably not correct, and then zero in on the ones that seem like they're the correct measurement. Again, this is this is not an absolutely perfect foolproof way of doing this. You can use a ruler if you care about perfection. Now I'm going to go and use that line that I just made as a guide so that I can slice off the extra clay. When this piece is off the mold and I'm in the finishing touches stage, anything that I'm not liking about the rim and its unevenness, I will be able to fix them. So this is not really a point of having to worry about perfect yet. All right. Getting rid of that, clay. 5. Using the hump mold: Now comes the moment where you get to decide how long you need to keep this on the mold. It really depends on what you're making. Depends on how thin the slab is. The thinner it is, the more vulnerable will be to warping if you take it off of the mold early, the thicker the slab is, the more easily it's going to hold its shape, even if you took it off the mold right now. What I recommend doing is always airing on the side of taking it off maybe a little sooner than you think you should just to avoid that problem of the mold obstructing the shrinkage. All right. So something about the mold itself. What I have here is a wooden bowl that I'm using, and it has a laminate surface. It has a kind of sheen finish to it, which means that it's not going to be perfectly absorbent. The best mold material is actually something that's very porous like plaster or just straight wood that doesn't have a laminate surface on it. But this one actually works pretty well. One thing you can do is if you have say, a glass bowl that you're wanting to use as a mold or something that y, it's not porous at all. It's very, very shiny and it's not going to absorb any moisture. You can potentially line it with some newspaper so that the clay doesn't stick to it. You could potentially use some baby powder or some cornstarch and sprinkle it on. If you're needing dough on a countertop so that the dough doesn't stick. You sprinkle that flour on if you've ever had that experience. That's similar. So you just want to create some kind of buffer between that slick surface that the clay is going to just stick to and not be able to let go. So I'm going to be setting this off to the side for probably about an hour, and then I'll be taking it off. So we'll check back in then. 6. Removing the hump mold: Okay. So this has been sitting for a little over an hour. And after an hour I checked it. It still seemed a little too soft, gave it a little more time, and now it's ready to go. Now, I want to make this clear that In this case, it was an hour and a half, you might find that it takes 5 hours. It might take 30 minutes if you're in a really hot dry environment and your clay is really thin. The time that it takes for this to set up enough for you to safely take it off the mold can vary greatly. It's up to you to decide when you try to peel the clay off, if you try to pick up the piece, if it seems like it's ready to go. And you don't push it if it still feels like it's stuck on there, if it's not popping off easily, or if when you try to lift it off, the shape is just like mangling in your hands under the pressure. So I tested a little bit. It's good to go. What I'm going to do is just carefully. If you want to, you can put a board here and then flip. But at this point, the shape should be firm enough that you can safely just remove it with your hands. If it's so fragile that you can't do what I just did, it means that it's not ready. So I'll get rid of the mold there and put it back on the wooden board. Now I have this little dish. Well, it's not too little. I would say it's like a salad plate. So I don't want to do the finishing touches on this yet because it's not leather hard. So I'm not necessarily waiting for it to be leather hard before it comes off the mold. I'm waiting for it to be halfway between plastic and leather hard. That's usually the sweet spot. I'm going to let this sit and I'm going to come back and do the finishing touches when it's leather hard, while it's sitting here, I want to be careful that I'm not letting the rim get too dry while the bottom stays moist, the bottom part and the walls. There's two options. One is if you feel like the shape can handle it, you can flip it upside down. I do think that this shape probably could handle it if I place it like that. If the bottom feels like it's going to slump down, or if that's a concern of yours, then maybe don't do that. I'll give you an option two for that. If you would like to let the piece sit right side up while it continues to harden before it's leather hard, you can take strips of plastic and wrap the rim. That way, as the bottom and the sides are drying. The rim stays a little bit covered up and protected from drying too fast, and this is going to make it so that the whole thing will be ready to go at the same time as opposed to the bottom and the sides being perfectly leather hard, but then the rim actually being bone dry. That's a really common problem in ceramics, is that the part that's most exposed to the air will dry fast and everything else dries slow, and then you end up with a problem when you're trying to do your finishing touches. So what I'm going to do because it's a pretty warm day, and I don't have to really go anywhere. I'm just going to focus on this for now. I'm going to put this aside and let it sit. My guess is probably two or 3 hours. It could be faster, so I'll be checking it probably every 30 minutes. By the time I'm at the point where this feels leather hard, meaning that I can push into the surface pretty firmly without making a print with my finger. I'm not pushing very hard right now because I can tell it's so soft that if I push hard, it will make a mark, or if I bend the piece a little bit, it actually will bend. It's not firm enough to hold its shape against the pressure of my fingers. So when it's firm enough that my finger doesn't make a mark, even though I give it a good push, but it's still soft enough that I pushed my fingernail into the surface, it would leave a mark. That's when I want to do my cleaning up. So I'll be checking it every so often, and we'll get back on camera when it's ready for the final phase. 7. Trimming and smoothing: All right. So this is now leather hard. I can pick it up, I can put a bit of pressure on it. I can hold it like this and it doesn't bend even just a little bit. If there was any slumping that happened naturally from holding it like this, that would be a sign that it's not ready. It's not leather hard yet. You want to feel like it's firm enough that it would take quite a bit of effort to bend or crush it. But of course, you don't want to do that. Now, this ended up sitting for about 3 hours. It was moved to the sun in the last 15 minutes. You can put your work in the sun. Just make sure that if you do that, you're making sure that the rim is wrapped or you turn it upside down. You can also use a blow dryer if you want to try experimenting with that, putting it in front of a fan. But all of these tips in expediting the drying process really are not ideal. The ideal is to let it just sit without any kind of forced drying because you're more likely to have an uneven dryness if you use those techniques. But sometimes you just got to do it. If you do make sure that you're again, wrapping the rim or putting it upside down. All right. In order to clean up this shape, I first want to focus on the rim. The rim here is looking pretty thick and I want it to look more elegant. You can create the illusion of thinness when you make the rim thin. That's not to say that thin is necessarily always better, but it does it does have a look of appearing to be more elegant usually when the rim is thin. To clean this up, I'm going to start by dealing with the rim by taking my sure form and starting to gently shave down this outer corner. If you wanted, you could focus on getting rid of the inner corner of the edge of the slab here along the rim with maybe the knife or maybe you could try with the sure form. But I want the shape to look a little bit more like it's curving in as opposed to opening up along the rim, so I'm going to get rid of the outside. Just really gently carving down this corner. And you never want to be an autopilot mode when you're doing this, especially when you're removing material from the piece. Don't ever want to slip into that state where you're just repeatedly doing a motion like a machine. Because even though the whole thing is generally the same shape, the slabs, the same thickness all the way around, you will sometimes have little spots where there's a bump or maybe something got a little bit thin from where you touched it in one spot. You never want to be in the mode of just being on autopilot where you're just cranking through a series of movements over and over and not paying attention. You really want to look carefully at every spot whenever you're removing material, because if you end up removing too much from one area, There's really no going back. You can't just attach it easily. There are ways to fix things up when we make a mistake, but it's never easy, and it's never simple. Well, sometimes it's easy and simple. But if you want to have a good technique and have a good habit, think about the process of removing material as like surgery. You want to really be paying attention. This is looking pretty good here. I'm going to turn it to the side so I can view it from this angle. I think that I would like to get rid of just a little bit more along this part here. It's hard to access when it's sitting flat, so I'm going to tilt the plate up. Clearly, if this piece wasn't leather hard yet, and if I moved it like this, held it in the way that I'm holding it, it would definitely damage the piece. Making sure that the object is firm before you start doing this process is really important. Because the slab itself was already pretty smooth, because I had used the metal rip to blend all of the little textures that were in it after I rolled it with the roller on the wood. Because it was already smooth, I actually don't want to go crazy with the sure forming across the surface because it already looks pretty good, and the thickness of the slab was created intentionally. I'm not trying to make it thinner. The amount of shirt forming I want to do on this thing really is just along the rim. If you decide that the whole thing seems really thick and heavy, you could go ahead and shirt form the whole thing to thin it down and make it a little bit lighter. But you'd be better off starting with a thinner slab, to be honest. That way, it's already the thickness that you need and it's perfectly even, and it's already smooth. That's looking pretty good to me. I think that what I'm going to do now is get rid of all of these crumbs. I'll clean the, get them off of my board here. Then I'm going to focus on smoothing out that formed texture on the outside. If it feels comfortable, you can put it upside down and see if you can get it from this angle. To clean up the sure formed texture. I'm going to use my metal rib by bending the tool, four fingers close to the curved edge, thumb and the middle tucked back, so I can bend it, get a really deep bend like a C or a U, and then scraping that texture. You're planing it, you're removing the high points of the texture. The remaining clay becomes level with the low points of that texture. Then after you've planed that, then you can compress. I'm using these fingers here, pushed into the curved end of this tool while I bend the metal rot and drag it across the surface. I'm putting quite a bit of pressure into the clay here. Again, if the piece was too soft and it was really damaging it, you'd want to stop, wait for it to harden a bit, wait for it to be properly leather hard, and then you can continue. If you notice anything else funky along the way, little textural moments that you want to tend to or get rid of, you can do that. At this point, I would probably take this opportunity to look at the rest of the piece, see if there's any little ds, something that I want to get rid of. This looks pretty good to me. Because it was made using a mold, usually this already looks pretty good, and that's part of the point of using a mold is that you don't have to do quite so much manipulating it to get the texture of the service that you want. It's part of the beauty of working with slabs, too, because slabs are inherently already good to go. Unlike a pinch pot or a coil pot. I'm going to flip this over, see how it looks. Then I'm just going to hit the sides of the top here. Looking for any spots that I missed. One thing that's the nemesis of someone who loves a smooth surface is these little crumbs of clay. You really can't avoid them. They show up when you're smoothing, when you're just managing to trim down something on the surface, and they're hard to It's hard to get them to go away honestly. What I recommend is that you don't fret, don't obsess about those little bits, and after you've completely finished, you're done with everything, then I'll show you how I would get rid of those. Before we get to that point though, now it's time to tend to the inside. This is the most important part of the piece, probably. Well, maybe the rim is the most important. I think maybe they're equal. Like I mentioned earlier, because it's a slab and because we used a mold, We would probably assume that this surface is already pretty much what we want it to be. But it might not be. If you want to take a moment to do a little bit of scraping, any spots that seem jagged or uneven or if you have just something funny going on, you can use your metal rib in the same way we had done before by scraping the surface. The thing with the metal rib is that it is a pretty firm edge, so it can nick the surface, especially when you're using it on the inside of a concave shape. It's a lot easier to avoid that nicking if you're working on the outside of a shape, like around a bulbus form, or if you're doing this across a flat surface. When you're on the inside of something, it's a little harder to avoid those nicks. If you're having them show up, don't try to fix them with this tool. There's a better way. We'll get to that as soon as this is done here. That's really all I'm going to do with this. Now, finally, the finishing move. These little crumbs in the clay. If I go ahead and blend them in, they're going to make a little dent or maybe a little flaw imperfection in the surface, so I don't want to be pushing them into the clay. What I'm going to do is grab a sponge with minimal water on it just a tiny bit of water. I'm going to squeeze out the sponge completely. There's no dripping or excessive amounts of water here. Then I'm just going to lightly pass over the surface here and pick up and maybe sweep away those little crumbs of clay. Get them out of there. You can also go along the outside too if you see little jagged edges or little spots of clay, those little crumbs there. Once those are mostly out of the way. The final stage would be using the red rubber rib to make a similar move that you make with the metal rib, but this will get rid of all of the little nicks that may have been left by the metal rib. It will also be your finishing touch to get rid of any skid marks that the crumbs of clay may have made on the surface when you were sweeping them away. This tool is much more easy to manage because it's so soft and it's much more gentle than the metal rib. As you're using this, you don't have to be quite so careful. When you're using a rubber rib to finish off a texture to make it smooth, the red one is the only one that you can use for this. If you find another rubber rib that's a different color, it's not going to be as soft as this one, and so it's most likely not going to do this work very well. If you're using a different rib and it's not working very well, that's why. We're basically in the home stretch of this. At this point, I'm happy with this. I'll say it's done. But if you are going for ultimate cylindrical symmetry, ultimate marble smooth quality, you could start to go back in and revisit some of the other steps after you've finished it to rework th the cycle. Maybe going back to this and hitting any spots that seem like they still need it. Compressing again, and then always ending with the rubber rib. When I'm going for something that's ultimate smoothness, perfection, I go through a cycle of these steps several times because sometimes you don't see imperfect spots until the whole thing is as smooth as it can be around it, and then you see ha, there's a spot I need to continue working on. But like I always say with hand building, and building is an opportunity for things to have character. This is not coming from a factory. It's not something that was made on a potter's wheel. It was made by your hands. And to leave a couple little signifiers of the fact that it is a one of a kind object, and one little mark or a slight tilt to it, it doesn't necessarily mean that it doesn't function well and that it can't be just as beautiful. So that's the takeaway there. That's the dish. 8. Final thoughts: I hope you enjoyed this demo on making a slab dish. Remember, when you are using a mold, it's a pretty cool opportunity to achieve precision and consistency across multiple pieces because you're repeating the same shape. It's a really good technique if you want to make a matching set. If you want to fire and glazer work, please check out the PDF I've included. It covers a lot of information about how to find access to firing and glazing opportunities. Did you know that clay is one of the few art materials that we can recycle? If you make something and it doesn't turn out very good, there are ways to reuse that clay, nothing's been wasted. So B bold and take risks with your clay practice. Thanks again. Have a good day.