Convergent Series

learning, using & teaching metal clay, and other aspects of life

Posts Tagged ‘drying’

How long did it take you to learn how to do this?

Posted by C Scheftic on 2013/05/30

So far, I have not made many pieces out of steel. I have used bit of steel as small accents, but only a few times as the main element in my work.

But, over the last few weeks, a number of us who work with and teach about Hadar’s Clays have been doing some explorations with the “Low Shrinkage Steel XT” product. Shown is a photo of a dozen pieces, which are about half of the ones I made during this exercise. While most of them turned out pretty much as I would have expected, there were a few surprises that I’m still trying to understand. I will likely have to make a few more pieces like the surprise-ones (when I find some more time to just explore), to see if the pattern repeats or if the surprises were nothing more than the occasional surprise.

Specifically, we’ve been looking at shrinkage. All metal clays shrink from when you first shape a piece in that medium to when it ends up as fully-sintered metal. Different products shrink different amounts. Some shrink more as they dry (go from wet clay to what we call greenware); others shrink more as they are fired (as the binder burns out and the atoms sinter (arrange themselves into a regular metal structure)).

Even working with just one product, different pieces will shrink different amounts in different directions. This leads to some interesting results, such as the fact that rings (usually) shrink smaller (though how much depends on the size and shape of the ring), the clay around cracks (usually) shrinks away from the opening (thus making it look larger after it’s been fired), and holes (usually) remain about the same size (depending on how big and what shape they are in relation to the clay around them).

With my background in mathematics and statistics, I tend to think of shrinkage as a “degrees of freedom” issue: if a clay wants to shrink a certain percentage and, for some reason, it can’t shrink that much in one direction, it compensates by shrinking more in the direction where it has more freedom to shrink. Except, it’s nowhere near as exact as that might make it sound…. It may vary from one time to the next. It may also vary from one artist to the next.

Why? Is it the amount of water in the clay? The humidity in the air? The altitude at which you work? The attitude with which you work? Phase of the moon? I could go on, but I think you get the idea: some variations are fairly clear while, for others, your guess is as good as mine! (Feel free to suggest additional ideas in the comments: I could use both solid suggestions and a few good laughs!)

But I write all this simply because I wanted to take a moment to say how much I enjoy exploring this entire “powder metallurgy” process: trying slight variations that go increasingly farther away from an original starting point just to see what happens. That is, in relation to the question in the title of this post (which I’ve been asked more times than I care to count) my answer is this: I hope to continue to learn as long as possible. I want to keep adding more information to my store of knowledge but, at the same time, I hope I’m never done learning!

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Bits & Pieces

Posted by C Scheftic on 2013/02/23

I’ve been meaning to write for a while about several questions that often come up in workshops, especially with beginners when each person is allocated a package of clay and then finds they don’t use all of it: why did you give me more than I need and how do I save it for later use?

I see the answers to these questions as being connected, but let’s start with the first one: for many “projects” it is just worth having a bit extra as you roll it out, so you’re sure to get a big enough area to cut out the shape you want. While this remains true no matter how experienced you become, it is especially important for beginners who are just learning the various ways to manipulate clay.

The answer to the second question is a bit more complicated. Silver clays come in a well-sealed package, and can remain in great condition for a rather long time inside that. The trick is that, once the package has been opened, all sorts of things can happen. At a minimum, the clay dries out. If that happens, it can be rehydrated: ways to add water to get it back to working consistency is something I’ll try to remember to write about at some point in the future (even though it’s not something I encounter myself on a regular basis any more…). If you’re going to use the remaining clay again fairly soon, you can just try to keep it moist. There are all sorts of products you can buy, or build yourself, to create a little humidified storage environment. The problem with doing that for any length of time (and something that the product vendors rarely address) is that your clay can easily become contaminated with mold. Now, you can add something to the environment (not to the clay itself, but simply inside your storage box) that can help retard mold growth. White vinegar or lavender oil are examples of some mold retardants. And, even if your clay does acquire a bit of visible mold, it’s not a crisis. At that point, your options are to scrape off the mold or to just work with it. (You do have to take care with the latter because the extra “space” taken up by the growing mold may create spaces in your fired piece that may influence its look and/or interfere with its strength.) But, in my experience, there’s a much better solution: don’t even try to store it!

That is, my general answer to both of the original questions is this: why not see if you can just use up any remaining clay in some creative and productive way?! Add to your current piece, or make something else.

One of the earliest “lentil” shape beads I ever made is shown in an old photo here, to the left, strung with some Russian jasper and green glass beads. (It’s also one of the pieces that led me down the path of making reversible pendants!) Its other / first side had a more elaborate design; what at the time I thought of as the “back” had the simple, low-relief, fleur-de-lis pattern shown here. After decorating the first side, I had a bit of clay left. I rolled it all out, just two cards thick, which got it big enough that I could cut out a small square. I put that on the same drying form I’d used for the lentil (so it would have the same curvature) and cut a circle out of the center of that. With the clay left over from trimming the square and cutting the circle, I made a number of little balls and let those dry too. Then, I moistened the center of the fleur-de-lis side and the underside of the open square, and stuck those two pieces together. Once those seemed secure, I added more water inside the open circle, and pressed the little balls into place. Having the circle around the outside of the balls gave me a way to make sure I could attach all of them securely, to that ring and to each other, rather than trying to count on a small point of connection on the bottom of each ball. And, suddenly, after investing only a few more minutes and a tiny bit of “left-over” clay, the piece became reversible, which sure seems like a good deal to me!

Of course, if you have more clay left over, you can always make something else with it. All of the elements in the silver and bronze earrings shown in the smaller image to the right were made when I had some larger leftover bits. After completing other pieces I’ve often used any remaining clay to make little patterned disks, or cut out little textured designs, and just set them aside to dry. When I’m firing up a load in my kiln, if I have a bit of extra room, I pop them in. When I have a few spare minutes–with metal clay, one always seems to have moments of waiting for something else to happen … to dry, to rehydrate, to finish firing or cool off, for example–I will go through these bits and pieces, and assemble them into something interesting. Their small size, of course, means they often (but not always) become elements in earrings.

Sometimes I’ll add other elements to such “bits and pieces” too. The orange-and-silver earrings shown at the very top of this post were done that way. When I fell in love with the little colored lucite flowers, I bought a small collection of them to use both for my own creations and during workshops. For several months, whenever I’d have a little bit of clay left over, I’d make a little flower disk or leaf of some sort. I kept track, so that I’d end up with matching pairs, but I didn’t worry about completing any particular number at once. I just used up what I could for some larger shapes, made smaller ones when I had less clay left, and made other small elements or even just tiny balls with the very end of the clay I had on hand.

In fact, for silver pieces that I intend to fire first and figure out how to use later, those I make flat. Then, when I do decide where I want to use them, if they need some shaping for that particular purpose, I can use the “traditional metalsmithing” technique of dapping the fired pieces to shape them as needed. That’s what happened to the little flowers I set on top of the blue-and-white glass beads shown with the earrings in the final photo here. In fact, though I made those flowers specifically to use with these beads, I could not have domed them to match their shape in the “dry” state because I punched them out of a little bit of extra / scrap clay that I had mixed up so it would remain flexible as greenware. I had finished the project I wanted to make with that clay and had some left then too. Since I knew that “flex greenware” clay that has been rolled out is great for using with paper punches, I used some of my leftover clay to make a small sheet for punching. I then made these flowers but they had to be fired flat … since they were too flexible to hold any other shape. (I also rolled the final bits of that flex-clay into long “snake” shapes that would remain flexible and could be used to embellish other pieces later on.)

I will note that, while fired silver and copper clays can be dapped after they’ve been fired to metal itself, the various bronze clays that I enjoy working with cannot be formed much (if at all) after firing. That’s just the nature of bronze, not simply the fact that it came from metal clay.

I do sometimes wonder how much this is something I do, myself, verus what other metal clay artists do with their leftover bits of clay. I know that a number of you do read this blog (without commenting) but I sure hope you will speak up now: Do you do this too? Or what?? And, why?

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