Rolling Along with Mica Powders

Fused glass koi dish

Mica adds sparkle to a finished piece of fused glass, but working with the powder can be tricky. Some artists will tell you that mica has to be capped because it won't stick to the glass. This isn't the case, but it is true that mica powder adheres only to where it touches the surface of the glass. Thus, the effect of the mica can be too subtle, and you often end up washing most of your mica down the drain when cleaning the glass after firing.

I have written previous blog posts with tips on getting the mica to better adhere to the glass surface. In the following tutorial, I'll show another way to use mica in your fused glass.

Materials

Clay rollers for applying enamel

Painter's tape

Clay texture roller (or other roller type with a design)

Black glass enamel (you'll want a true enamel like Thompson, not Glassline)

5x5" square of clear glass

(2) 5" strips of glass for border (width of tape, ~7/8")

5"x 3.125" dark-colored glass for center

Mica powder
Dust mask (when working with mica)

Step-by-Step

Apply painters tape to glass

Use strips of painters tape to mask off two opposing edges on the clear 5" square of glass.

Spread some enamel on a
piece of float glass

Spread enough enamel to coat the roller on a piece of glass. I use a piece of float glass.

Enamels come in premixed versions or they are dry and mixed with a medium prior to use. For this project, I have used Thompson high fire black, which comes dry, and I have mixed it with A14.

Note that whatever paint & medium you use, it should be at least somewhat slow-drying. In my experience, enamels mixed with Klyr-Fire, or pre-mixed Glassline paints, dry much too quickly. Screen-printing enamels are ideal because they have a fairly long working time.

Coat the texture roller with enamel

Coat the texture roller with the enamel by rolling it in the paint on the float glass. Roll it back and forth several times until the roller is evenly coated. Add more enamel to the sheet of glass if needed.

Roll the enamel onto the clear glass

Starting at the top or bottom edge, roll the enamel on to the masked off glass in a single motion. Don't roll back and forth -- this will blur the image.You'll notice my texture roller is just the right width to cover the area of the unmasked clear glass.

Don't worry if you don't get absolutely perfect coverage. Sometimes it's good to see "the hand of the artist"!

Sprinkle on mica powder

Wearing a dust mask or respirator, sprinkle the mica over the enamel-covered glass. Tilt the glass back and forth, gently bumping an edge with your hand to distribute the mica evenly. You can use a single color of mica or use multiple colors. In the coral koi dish at the top of the tutorial, I have used a rose colored mica and a gold colored mica.

Once the mica is evenly distributed, carefully remove the tape.  Hold the glass vertically and tap it on your working surface to knock off the mica that is not stuck to the paint. If you do all this mica work over a sheet of paper, you can recover and reuse what doesn't stick.

Now for the fun part...Once I've knocked off all I can, I take the piece outside and, using good ole lung power, I blow across the surface of the glass several times. This generally will remove all the mica from the unpainted glass surface, leaving your enameled surface nicely coated.

Bottom pieces of glass

Now it's time to work with your three colored pieces of glass. I recommend using darker colors for the center glass. Here, my picture shows a white piece of glass. At the last minute, I changed this to black because the gold mica that I used would be mostly lost against a light background.

Lay-up in the kiln

Place the three colored pieces of glass on shelf paper in the kiln (I like Papyrus). Top these pieces with the clear piece of enamel/mica-coated glass, mica-side up.







Let's talk a little about this lay-up. Given that we are capping three pieces of glass with a single piece, we've got major bubble trouble brewing because we are creating potential air pockets under the single-sheet cap. I mitigated the chances of bubbles in three ways: (1) placing the glass on shelf paper, rather than directly on the kiln shelf (this provides a way for air to escape); (2) accurately cutting the glass so the bottom pieces fit tightly together; and (3) a good bubble squeeze in my firing schedule.

Here is the schedule I used:

Segment	Rate	Target Temp  Deg F	Time     (minutes)
1	300	1100	30
2	50	1250	60
3	300	1460	10
4	AFAP	950	60
5	100	700	00

The slow ramp in Segment 2 up to 1250 and the long hold at that temperature comprise the bubble squeeze.

After this full-fuse firing, I cleaned the piece and then slumped it using my usual schedule.

I hope the information above has given you ideas for creating unique glass pieces using texture rollers. More images can be found below!

Happy rolling! Dana

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Close up of koi dish - rose and gold mica

Blue small dish - vine-pattern texture roller

Vine-pattern texture roller - front view