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How to Inlay Glass into Wheel Thrown Raku Pottery
Posted By Steven Branfman On May 23, 2011 @ 9:27 am In Daily,Features,Raku Glaze Recipes | 27 Comments
Placing broken glass inside bowls and platters to melt and pool in the glaze firing can create lovely surfaces with lots of depth (though these surfaces should be tested for food safety). I’d seen that technique used many times to great effect, as well as the technique of embedding little pieces of glass here and there as embellishments on pottery. But I had never seen anyone inlay glass exactly like Steven Branfman does.
Steven throws a cylinder and then rolls it in crushed glass. Then he continues throwing from the inside (so as not to cut his fingers!) to shape the pot. In today’s post, Steven takes us through the process step by step. Plus, you can download Steven’s raku glaze recipes in our latest free download 15 Tried and True Raku Glaze Recipes: Recipe Cards for our Favorite Raku Pottery Glazes. – Jennifer Harnetty, editor.
COMBINING CLAY AND GLASS
I began incorporating glass into my work about 25 years ago as an effort to unite two apparently similar materials. Clay and glass are at least cousins if they are not siblings, and although clay was the material that I was connected to, glass held a certain interest.
My first efforts involved incorporating the glass as “windows” through the surfaces of my pots, connecting the glass in the fashion of leaded-glass technique with clay cutouts in the wall of the vessel acting as the frames for the cut pieces of flat glass. At the same time, I was using bits of glass as decorative elements by laying them flat inside bowls, dishes, plates, and platters, and allowing them to melt into the surrounding glaze. Combining these two materials proved to be much more difficult than I had thought it would be. These experiments with glass took place along side other work that was proving to be much more interesting and engaging and soon my interest in the glass all but disappeared.
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It wasn’t until some years later that the glass idea re-emerged, although from a completely different perspective. From very early, my pots have been about the relationship between the surface of the ware and the form. As I matured as a potter and a maker of vessels, my understanding, interpretation, and representation of the vessel became, and continues to become, more precise, sophisticated, and personal.
How the interior space of a pot shapes, defines, and gives life to what we see on the outside is elemental to how I conceive and make my ware. I form pots from the inside out and the bottom up. And while pressure and force on the outside of the clay during the throwing process is a key element to controlling the shapes and sizes of the forms, it is the inside pressure that I exert that actually creates the pot.
The surface of a pot is more than a simple canvas upon which to decorate or embellish. It is a skin that contains and thus expresses and communicates all of the power within. The incorporation of crushed and inlaid colored glass is yet another method I use to articulate and embody that power.
As with most craft methods, there are many nuances of technique, method, and personal style that are not possible to demonstrate within the limitations of the printed word. Start your experiments with small amounts of clay and simple shapes building up to larger, more complex forms as your skill improves. Don’t be satisfied until you have incorporated this new method into your own language of shape, color, texture and form.
There are four steps to the technique:
1.Forming a cylinder
2.Inlaying or embedding the glass
3.Forming the shape by expanding it from
the inside out
4.Finishing the piece.
Although my work is all thrown, with modifications you can easily adapt this technique to slab work.
You must throw your form on a bat. Plastic bats that tend to bend are not recommended until you have more experience with this technique. (You’ll see why later.) After using liberal amounts of water for centering and the first few pulls, I dry my hands to throw the rest of the clay completely dry.
Note how little water is visible in the photos. Dry throwing leaves the cylinder strong and able to withstand the stresses that the clay will have to withstand later in the process. The cylinder must also be formed with very even walls that are left thick enough for the glass to be embedded and subsequently expanded. Dry throwing is a skill all to itself and one that will take a lot of practice to master.
When you complete the forming, the clay should feel somewhat stiff (though not nearly leather hard) and dry to the touch. Depending on how dry you throw, you can put the cylinder aside until the surface wetness dries. If you do that, be sure to maintain even drying, not allowing the cylinder to warp or bend and not allowing the rim to get dry. Tip: Before you lift the bat off the wheel, mark the pins and corresponding holes in the bat so you can put the bat back on the wheel in the same orientation.
While the cylinder is setting up, I prepare my glass. I use random varieties of flat, colored glass used by stained glass workers. You can use any type of glass available to you, including bottle glass, marbles, and glass rods. Wrap the glass in canvas and simply crush it with a hammer.
On the table I lay out my glass carefully choosing colors, sizes of glass (from large pieces to dust), and the arrangement of the glass in patterns and shapes visualizing how these patterns will transfer to the surface of the clay.
The cylinder will be rolled onto the glass, so as you lay it out pay attention to how close to the rim and the foot the glass will be inlaid. You must be able to finish throwing the neck and rim of the piece without touching the glass and then trim the bottom and foot (if you choose to trim) without running the tool over the glass.
Holding the bat almost as a steering wheel and supporting the cylinder from the inside, roll the cylinder in the glass. This is where a rigid bat and stiff clay is critical.
Place the cylinder upright and paddle the glass into the clay still supporting the clay from the inside to maintain the integrity of the cylinder.
Each time the clay is rolled onto the glass, it is to enhance the pattern and the coverage on the vessel’s surface. Repeat this process until the surface is as you want it.
The more you roll the cylinder, the more it will become stretched and distorted. Work carefully to minimize the distortion.
To combat distortion, gently return the cylinder to its vertical form by grasping the cylinder around the outside, pushing it and pulling it back into shape.
In preparation for continuing the throwing process, collar in the top of the cylinder.
Throw the top of the cylinder slightly to re-orient and re-center it.
If you’ve never done any one-handed throwing, this next step will take some practice to arrive at a comfortable personal approach. The more centered (meaning evenly thrown walls) the cylinder is, the more success you will have in one-handed throwing.
I use my left hand inside the form to raise the clay and push it into the shape that I want. Yes, even with only one hand you can still dig into the clay and raise it! Hold and control your left hand and fingers just as you would if you had your right hand also working on the outside. A slow, careful approach works best. I alternate between using my hand and using a rib to expand the shape. Curiously, although I use my left hand inside the pot for throwing, I am more comfortable and have more control using the rib in my right hand.
When you use a rib, be careful to hold it as flat as possible (not at a 90-degree angle) against the inside wall so you don’t scrape clay away. The idea is to push the clay outward, not to scrape clay away and unnecessarily thinning the wall. As you expand the wall and it gets thinner, you’ll feel the texture of the glass. It will take practice and experience to learn how much you can expand the vessel before you stretch it too much!
For some great raku glaze recipes, be sure to download your free copy of the newly expanded 15 Tried and True Raku Glaze Recipes: Recipe Cards for our Favorite Raku Pottery Glazes.
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