Watercolor fritteries

To tell the truth, I don’t think I’ve made traditional fused glass–a full, flat fuse of a bunch of cut sheet glass pieces that I then slump into a vessel form–in a long time. That direction seems a lot more limited compared with the near-infinite number of things you can do with frit.

Frit, or crushed glass, is screened into powder, fine, medium, coarse and extra large sizes, ranging from about like superfine sugar to grape-sized flat chunks (at least when you use Bullseye or Uroboros frit–it’s different when you get into casting and blowing crystals). Each frit size produces very different effects and, interestingly, isn’t really interchangeable in a work.

Most of the time, frit textures so delight me that I go out of my way to keep them intact, by tack-fusing them together at the lowest possible temperatures. This gives me very crystalline-looking structures that catch the light beautifully but remain surprisingly sturdy. I do a lot of production work like the Crystals, Sand, Shards series that way.

When you’re working with frit, particle size, volume and air incorporation become critical, exploitable factors. There’s a lot of air inside a mound of frit, and when it’s heated the glass tends to compact and push out some of that air, leaving you with a much smaller volume (and also a lot of bubbles that interfere with transparency). To fuse sheet glass into a work one-quarter inch thick, you simply stack a quarter inch of glass onto the kiln shelf and fuse away. To fuse a bunch of frit and wind up with a quarter-inch of glass, you’ll need a lot more frit. If you work with nothing but glass powder, for example, the work can shrink by more than 50 percent, so you’d need AT LEAST a half-inch of powder, well-packed.

FYI, many artists do something similar to this with stacked glass layers–you use frit to decorate successive layers of clear glass, fire them separately and then stack and fuse them together in a final firing. Catharine Newell is one of the pioneers of this method. I did this peach that way in a Bullseye “Working Deep” class; it’s about 6×6 inches and 1.5 inches thick (below).

If you use pure frit, though, you can take advantage of the lack of planes to obtain even more dimension. A quarter-inch thick work of sheet glass has up to four layers on fairly flat planes. A quarter-inch frit work can have many, many more layers at different angles, letting you achieve very painterly, watercolor-like effects.

I got into this from working pate de verre; I’d have mounds of frit tints left over and needed to do something with them. So I piled them into shallow molds, packed well, and just fired to see what would happen. They blended and became very dimensional in the mold, more like watercolor than glass.

A couple of galleries saw the result and asked if I could do the same thing in larger wall panels, so that’s what I’ve been experimenting with. I’m happy with the results, although I’ve found that getting the depth and saturation of color takes a lot more effort than the final form suggests. I’m calling it the Watercolor series, for obvious reasons.

(BTW, I don’t want to imply that I invented this–lots of artists fuse trays of frit into gorgeous, layered art, including Roger Thomas, Kathleen Sheard, Patty Gray, Miriam diFiore and probably ninety-leven others. This just happens to be stuff I’m doing.)

Istart with a glass tray made out of a 3mm clear glass base (I tend to prefer using Bullseye Crystal Clear (1401) because it contributes nothing to the colors underneath). I superglue 3mm clear sides to form the box (they’llwill be cut off after the final fuse). This gives me a shallow, fillable tray with perhaps 1 inch sides. Then I’ll sketch out my design on the bottom of the glass, and start filling.

Still, for me, working with pure frit produces a thinner piece–important especially for weight and light transmission concerns. And since I’m not restricted to placing frit on static, parallel planes, I can have as many planes and layers of color as I’d like, angling them into and out of the glass as needed.

So, I start by figuring out the dimensions of the piece I need and construct a glass “mold” to hold the frit, a box made of fusible glass. It’ll melt into the work during firing and give me some edges I can trim away to get perfectly parallel, square-cut edges. (I visit waterjet cutter John Groth for that part) I generally use standard 3mm clear glass for the bottom (if you use crystal clear or “water clear” glass you’ll have the truest color from the frit).

I decide on the final depth of the work (here, it was 3/8 inch) and cut sides to fit my “box base” that are at least 2x the final depth–in this case I made the sides an inch high. Remember, you’re going to use at least 2x the depth of frit so the sides much be able to hold at least that much.

For the initial fuse, I work from the bottom up, that is, the frit closest to the clear glass on the bottom is actually the face of the work. This gives me a bit more control over color placement (not really an issue in this example) and any line drawing. It also allows me to reference any areas that need light transmission–I’ll mostly fill the tray with coarse clear frit and only thin layers of color there–or those that need maximum saturation (I’ll back those areas with opal frit). I work on a lighted drafting table, which lets me see through the layers.

I use a lot of frit tints, i.e., fine or medium clear frit, coated with a tiny bit of opal (and usually dark) colored glass powder. I picked up the technique from Linda Ethier, although it’s also part of Bullseye’s frit tinting instructions now: You measure the carrier frit into a jar, mist in a little water, add your powder, cover and shake like crazy until the powder is evenly distributed. The fine clear dilutes the powder color and adds a lovely translucency. (And the real fun starts when you begin mixing powder colors in a single tint)

Frit tinting gives you almost infinite color combinations, as I’ve said before, and offers a chance to build fine shadings into your work. I like to “build” colors down into the piece, meaning that I’ll start with perhaps 5% powder/95% clear in a small area on the tray bottom about 1/16 inch thick, add a slightly larger area of 20% powder/80%clear mix in the same shade on top of that, and so on. Depending on your color choices, you can get a very dimensional look that way, especially if you’re overlapping colors.

It’s tempting to throw every frit color I have on the tray–especially since frit is usually much lighter than its fired color so it doesn’t LOOK that much different. I’ve learned to stick with only a few–no more than 10 plus clear in this piece, which measures about 27×30 inches when finished. Except for “depth points” that will go all the way through the piece I also begin to pull back color in the last half of the fill on the first fire, going to nearly all clear medium frit to prevent muddiness and keep things translucent.

I’ve learned not to try and complete the whole piece in a single firing but instead to start light and saturate the colors in successive firings. Multiple firings give me the chance to adjust colors and add depth as the piece begins to come together. I can always add color saturation; it’s awfully hard to take it away.

In the image above two of the trays are in the kiln, ready for firing; you can see how much clear is on what will be the bottom of the piece. I’ve placed them on a sheet of thinfire and dammed the edges with 1/8 inch fibre paper, surrounding the whole with kilnbricks.

It’s a long firing; I go through a lengthy bubble squeeze from 1000 to 1240 F and hold for a half hour to ensure I’m driving at least some of the air out, add a post-fuse “relax cycle” where I dip below the glass’ strain point, briefly rise above and then drop below again before annealing to prevent bowing or cracking of such long rectangles, and then double the anneal soak and make a slow cool down. I’m probably too conservative, but these things are a lot of work and I’d rather wait than have to turn them into potmelts.

Most of these go through at least two firings; the first gets the color and depth into position; subsequent firings add color saturation and detail. Above is after the second firing; between firings I evaluate the piece, mark out areas that need more color or detail, add frit, and return it for another firing. (There are three in this triptych.) In this shot you can see the color notes and also some of the additional frit at the top.

The finished piece, edges cut off and awaiting framing and mounting and a “real” photography session (excuse the hasty snapshot), is at the top of the page.

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