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We often get the question, "What do you do with that leftover glaze you don’t want?"
Most potters, when they have a glaze they don’t like or that isn’t working for them anymore, pour all such glazes into a single bucket. These mixes are typically called “slop glazes.”
Test the slop after a while and see what glaze you’ve got. Often it is green or brown color. It may be a nice liner glaze or even a decorative glaze. Some people separate their light color glazes from their dark color glazes, or separate their food safe glazes from their non-food safe glazes.
But what if the glaze is contaminated, or you don’t have a use for slop glaze? If you are sure it has no toxic chemicals (AP non-toxic label on commercial glazes), you can dispose of it easily by pouring it down the sink (also OK for sewer or septic) or throwing it away with the trash.
Many glazes after all are just clays and fluxes. But if the glaze has toxic chemicals, or if you’re not sure if it does, the best thing to do is put it in a bowl of bisque and
fire it. This will lock in the toxins permanently. Then you can throw the piece in the trash.
If firing the toxic glazes isn't an option, call your local waste disposal company and tell them what chemicals are in your glaze, and they will tell you how best to dispose of it.
Do-It-Yourself, or DIY, projects are insanely popular all across the crafts world, and ceramics is no different. Here's how to make your own glaze!
Equipment and Materials
To mix your own glazes you need:
- A sieve.
- A mixer.
- A scale.
- Glaze recipes.
- A mask.
- Two buckets.
Find a Glaze Recipe
Typically one starts by finding a glaze recipe, from a book or a reputable website. Start with a glaze recipe which is formulated for your particular firing type and clay body (i.e. stoneware clay, fired in cone 6 oxidation). Recipes are usually expressed in numbers that always total 100. For example:
- Ingredient A: 10
- Ingredient B: 25
- Ingredient C: 15
- Ingredient D: 50
Determine the Amount of Glaze You Want to Make
Determine the amount a glaze you want to make and then add the appropriate ratios. For example, if you want to make 1000 grams of glaze, you would add:
- 10 / 100 * 1000g of Ingredient A
- 25 / 100 * 1000g of Ingredient B
- 15 / 100 * 1000g of Ingredient C
- 50 / 100 * 1000g of Ingredient D
It is wise to mix a test batch of 100-500g first, to make sure the glaze works as you want it to. Glaze chemicals are measured using a scale.
You don't have to throw away all your clay scraps, but recycling them doesn't need to be a chore either. Here are some ideas for the environmentally-conscious potter.
- Throw with two separate buckets - one for clean water, one empty one for wiping the clay from your hands into. So, if you're right-handed, dip your hands in the right bucket of water, throw, then when they are full of clay, wipe them on the edge of the clay bucket on the left. Every so often wipe the clay off the edges and down into the bucket to keep it from drying out.At the end of the day, wedge the clay back up and make your last piece. If it is too wet, squeeze it into a long cylindrical shape and put it on a table curved like an arch. This exposes more surface area and will dry it out faster. Or try it the next day. Depending on humidity and temperature levels may need more or less time. Check it and cover when it is the right wetness.
- Another thing to do with throwing scraps is pour the slurry into a kitchen colander lined with a sheet of newspaper. Excess water will filter out. Note: Clay processed from throwing slurry is very plastic and nice to work with!
- After you've been working with clay slabs and you have that pile of scraps, dip them in water and place them in a plastic bag. Wrap tight, leave a couple days, then wedge and use it.
This week's tip is actually a fun handbuilding project you can make whether you are a beginner or advanced potter, and even children and friends can get into it. You will find a bottle to use and because you are making it out of clay yourself, it includes the beauty marks of the maker and no two will be alike. You could texture it, put designs on it, or glaze it funky colors.
- Wrap newspaper around your bottle and tape it on well. Wrap a second piece of newspaper over the first and tape it together so it stays on. Don't connect the two layers of newspaper. The inside layer of newspaper is going to stick to the clay, so if you want to take it apart before the clay shrinks and crushes, you need the first layer to slide off the second layer.
- Now roll out big sheets of clay. The easiest way is with a rolling pin. Get two sticks about 1/4" thick and put one on each side of the clay, then pat and roll the clay down until the edges of the rolling pin hit the sticks on the ends. This gives you a uniform thickness of clay 1/4" thick. Make sure you roll the clay out on canvas, cloth or paper or it will stick to your kitchen table.
- Now, pretend for a minute you were just making a glass bottle with no neck. Cut a rectangle that is approximately the height of the glass, and wide enough to go around the glass. Start with the glass at one corner of the slab, and roll it around until the other side covers it and makes an overlap. Cut a slice down the middle of the overlap, peel the leftover pieces away, and the ends should match nicely. Apply vinegar and push the edges together, smoothing them over. If your clay is stretched a little, you can just beat it back into shape with a paddle or a stick of wood.
You can do some interesting things by using tape as a resist. You can make straight or wavy lines, and geometric shapes. Here are some ideas.
About the Tape
Masking tape is the most basic option, and while it has some disadvantages (it can absorb, it can tear while you’re pulling it up, and it doesn't stretch), it can be a good place to start.
Blue painters' tape is probably a little better. Electrical tape works well and stretches somewhat. Another option is Chartpak which is a graphic artists' tape and comes in various widths. Drafting tape is another option, as is auto pinstriping.
Make sure the tape is stuck down well by burnishing the edges with a fingernail, edge of a spoon, or wood tool.
Remember that the wider the tape, the harder it will be to get it to stretch evenly over a curved surface. But don’t stretch too much or the tape will try to pull loose.
Coil building is a great way to build pots, sculptures, and just about anything. You can build all kinds of shapes, from structured "perfect-looking" pieces to very organic pieces. But as anyone who has tried to roll coils can attest, it is not as easy as it looks!
Beginner's coils tend to flatten, get hollow on the ends, be lumpy, or break into pieces. This tip will focus on how to roll nice, straight, even coils. And next time we will talk about using the coils to build beautiful and interesting objects.
Start by squeezing the clay into a sausage, and taper the ends slightly.
Some people do the first rolls of the coil in their hands, then lay on the canvas.
- Use clay that is soft enough.
- Hard clay tends to go hollow on the edges, although starting with tapered ends and keeping the canvas moist will help.
- The heat from your hand can also dry out coils.
- Soft coils are better anyway for joining, and slip is not needed.
- But if clay is TOO wet, it can cause problems too. If rolling on a canvas, dampen it slightly. Otherwise the canvas will dry out the clay.
There are two approaches to rolling:
- Use your whole hand (palm + fingers, fingers spread wide).
- Use just the outstretched fingers.
Almost 10 months ago, I became a mother for the first time. This has been a journey unlike any other, including my 10 year career in ceramics. After my daughter was born, I resigned my high school ceramics teaching job and opted for the stay-at-home mom life.
This was a big adjustment since I’d been in the career world for so long. To beat the isolation and lack of socialization, I joined a stay-at-home moms’ group. I know, it sounds funny, but really, it’s awesome! We have play dates, potlucks, and crafts at the mothers’ homes and at the local parks. I thought, “Well, I know how to teach and I have all the materials; let’s do a clay craft at my house!” But, I had to think about the fact that we had limited time. I wouldn't be able to have them make the pieces, come back after the bisque fire to glaze, and then come back yet again to pick up the finished pieces.
So, I needed to figure out how to get the kids’ projects created and glazed in one sitting. I hardly ever use low fire glazes, underglazes, or slips. I do Cone 6 at home in my Skutt electric kiln. I took a chance and ordered some Amaco Velvet Underglazes, which are primarily meant for low firing and known for their vibrant colors. I got red, orange, brown, and green.
There are a huge number of ways to decorate a thrown-clay vessel including piercing the wall of the vessel to cut in a design or carving the inner or outer wall of a vessel while the clay is leather-hard. For an even more interesting and challenging project, consider piercing and carving a double-walled thrown vessel like a vase thrown with porcelain clay.
The first step is to throw the vessel. There are many videos available on the internet (e.g. YouTube) demonstrating how to do this. Once the double-walled vessel has been thrown and allowed to dry to leather-hard, follow these steps to create a pierced and carved design.
- Create a design on paper if you are not comfortable simply free-handing one. Cut out the design and spray it very lightly on the back with water and lay it on the external wall of the vessel. Trace around it very lightly with a pencil. Make sure you deal with the area where the external wall air hole is first. Locate your design so that it incorporates the air hole into a portion of your design that will be cut out.
- As you pierce and cut using a craft knife remember that the clay you do not cut away has to support the exterior wall so leave enough connections at the top and bottom to provide this support.
- Be careful, especially at the top and bottom of the external wall not to cut into the inner wall of the vessel.
To me nothing adds more life to pottery than texture! It creates varied dimensions to a piece that your glazes will respond to. It literally awakens your piece.
I started exploring texture on my pieces a few years ago and bought many of my texture tools right here at Big Ceramic Store.
The one place I really wanted to add texture was inside a plate or bowl. Adding the texture after it was thrown proved to be nearly impossible. I then stumbled upon a solution. Add the texture BEFORE throwing!
Try this approach:
- Center your clay and then bring it down until it is wider than what you want the final piece to be and is in the shape of a thick round cookie.
- Smooth the top and let it spin on the wheel for a minute or two to dry.
- Take a textured stamp, roller, or any material that will leave a design, dust it with cornstarch.
- Take a textured stamp, roller, or any material that will leave a design, dust it with cornstarch.