Art Glass Clay. Firing glass in the microwave!

I’m really excited about this: Art Glass Clay.  Imagine.  Glass you can actually mold with your own two hands, and fire at home! That’s kind of like alchemy to me.  I needed to know more.

I did an overview segment on Home and Family, with clay and instruction we got from artist Paula Radke.  It was fun, and a good place to start, but frankly, one could spend a LOT of time learning about this clay.

It’s a powder, that you mix with water, add some heat, and it becomes glass.  You can mold it, stamp it, sculpt it… it’s really pretty amazing stuff.

Here’s the lowdown:

The powder is 99% smoothly ground glass, mixed with a small amount of organic binder, that’s what makes it behave like clay.

It comes in 24 colors, in 2-ounce jars, and they cost between $12 and $18 each.

You can make 4-5 large pieces or 6-8 smaller pieces from one jar.

The clay shrinks about 20% during firing.

You can make beads, pendants, ornaments, earrings, buttons, even drawer pulls!

Here’s what you’ll need:

Art Glass Clay

Molds/stamps/sculpting tools

Water

Mixing Bowls

Knife or palette

Files, sand paper

Olive Oil

Parchment paper

Kiln.  We’ll talk more about that later.

First:

Mix powder with water.  The ratio is roughly 2 parts powder to 1 part water.  Start with a little less than 1 part and add as you go.  You can always add more water.

Mix in a glass bowl with a knife or offset spatula.

When it begins to hold together, pick it up and knead/roll with your hands.

At this stage, the clay will keep indefinitely in an airtight container.

Molding your clay.  You can use polymer clay molds, molds made specifically for glass clay, I’ve even used candy molds.  Silicone molds work best.

Next, prepare molds.

Brush with a little bit (not much!) of vegetable oil as a release agent.

Press clay into mold, make sure it’s well pressed, and no air pockets are hiding.

Turn mold over, and pop the clay out onto a piece of parchment paper.  This will make it easier to transport the finished clay pieces while they are drying.  If you want to add holes, do so while clay is still wet.

Set aside to dry.  Medium sized pieces take about an hour to dry at room temperature.   You can also dry in a 200-degree oven.  Turn over to make sure it’s dry through.

**Make sure your piece is completely dry before firing – any water in the clay could cause it to super heat, and crack or explode.  And that’s a pain in the glass.

Once dry, sand or file away any bits, rough edges, sharp points, etc.  Use emery boards/jewelry files, sand paper, etc.  Be careful, this is when your piece is at its most fragile.  While sanding, work over a piece of paper.  The filings can go right back into the jar and be rehydrated later!

Firing:  If you have a kiln, lucky you.  Perhaps a friend does, or there’s a studio nearby that will let you fire in their kiln.

In my experience, the clay fires best in a standard kiln.  But if you don’t have access to one, you can get a microwave kiln.  This is a fiber-ceramic 2-part vessel that has a special liner that allows it to get super hot.  Remember, the glass has to get over 1000 degrees!

Microwave kilns can be found online or in specialty glass stores. The one that is recommended is made by Paragon, and can be found here.   It’s not cheap, but considering all you can do with it (you can also fire precious metal clay in it too!), it’s worth the investment.

If you have a tiny one like mine, you really can only fire small pieces – a quarter or smaller.  My kiln only cost $70, but if you have a larger one, you can fire larger pieces.  Kilns can range up to $300.

Microwave kilns vary by manufacturer, be sure to read and follow the instructions for your specific kiln.  While there are differences on how to use and/or set-up microwave kilns (some require kiln paper, others a kiln wash, etc.), the actual firing method stays the same.

Perfecting firing techniques takes time and practice, but anyone can do it.  Be patient, and you will be rewarded.

Microwave firing:  Begin by setting the kiln in the microwave oven and heat for 1 minute.  Using a heat-safe mitt, lift the lid of the kiln to view it… only do this for a few seconds.  Put the lid back in place, then microwave for another minute.  This allows your glass piece to “breathe” and absorb the heat more evenly plus you can monitor its progress.

Next, microwave for 30 seconds.  First the piece will turn black – that’s the binder burning off.  In the next intervals of firing, the piece will return to the dried color, then eventually begin to get glossy, and may even glow red-hot.

Continue in 30, 20 or 10 second intervals, until your piece looks sufficiently shiny.

(For more detailed instructions on firing clay go here.)

Depending on the size of the glass piece, it will take approx. 5 minutes to fully fire in the microwave.

When you are finished, let the glass cool down for a minimum of 30 minutes.  And, at the risk of stating the obvious, DON’T TOUCH IT WHEN IT’S HOT.   

Once fired, the piece is 100% glass.

Until you get the hang of firing, I recommend using pieces you haven’t spent a lot of time making. Also, using molds creates beautiful detail with minimal effort but start with only one color at first.  That way if you have a failure, it won’t be devastating.

 

I’m a big fan of this clay.  Be safe, be creative, I hope you enjoy it!