Watercolor fritteries

Home>glass>fusing>Watercolor fritteries

watercolorsTo 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.

crystalssandshardsMost 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).

peachIf 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.

watercolorplateI 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.

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

I start by figuring out the final dimensions of the piece I need, add about an inch, and construct a glass “mold” to hold the frit. It’s a 5-sided box of clear glass. I use a base of standard 3mm clear glass–I prefer crystal clear/water clear because it contributes nothing to the frit colors–then cut 1-inch strips of the same glass and superglue them all around the edges.

Watercolortray1Patty Gray uses a similar method, only with hot glue. I found that the superglue held better, although you must be careful to make straight, not angled cuts. DO NOT ASSUME that the superglue will actually do more than lightly contain the frit though; if you try to pick a frit-filled glass tray up by the sides you’ll wind up with mucho glass on the floor.

The box walls are so high because of the initial volumes of frit required. Your piece will compact itself by at least half. The box walls will melt into the work during firing and give me plenty of space to trim the final piece into perfectly parallel, square-cut edges (I have a local guy with a waterjet cut them for me).

Now I lightly sketch my design onto the inside of the box(es) with a Sharpie marker and set each box up on small paper cups, which gets it off the table and makes it much easier to lift and maneuver. (remember, you can’t pick these boxes up by their superglued sides)

Watercolortray2And I start filling. The outside bottom of each box will become the front of the work, remember, so the frit that’s right on the clear glass bottom is what will be seen first. I work on a lighted drafting table, which lets me see through the layers, and I tend to mark up the areas that need to stay light or very translucent.

In those areas I’ll keep the powdered frit to a minimum, often just a covering on the bottom of the box, and then fill in with coarse clear or pale transparent frit. For areas that need maximum color saturation, I’ll put much thicker color layers there, and at some point sift on a layer of opaque powder (usually white).

This stops the light and brightens colors.

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. Bullseye has a nice introduction to frit tinting on their website but, basically: 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.

Watercolortray3The 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% colored powder/95% clear powder 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 measured 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.

Watercolortray5I’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.

Watercolortray4It’s a long firing; I go through a lengthy bubble squeeze from 1000 to 1240 F and hold for an hour or more 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, back from the waterjet cutter, gets its hangers (in this one I’m using Hang Your Glass standoffs), and that’s about it. I have the option of firepolishing to round over the edges, or simply coldworking the edges to a sharp polish, but it’s not really necessary.

Embarrassing admission as a postscript: If you’re observant, you’ll probably notice that the process steps show a the red central mass pretty much occupying the upper right diagonal of the triptych. The final photographed piece, however, doesn’t, because the panel is upside down.

I made this work about three years ago, in a kiln that would only hold two of the three panels. I fired the center panel separately, and it seems to have gotten the idea that it doesn’t BELONG in this piece. When I placed the three together, that center panel leapt out of formation and cracked off its corner. I had to refire it to bring it back in alignment with the other two panels.

Took it to the waterjet cutter, who called the next day to tell me the center panel had broken. Apparently he cut the first two pieces without incident, but on the third panel something caught in the nozzle of his waterjet, it skittered across the face of the panel and cut it almost in half.

He refired it and recut it, retrimming the other two pieces to match. I mounted the piece, put it on my fireplace wall, and thought no more about it for three years.

Then a gallery owner visited and asked to borrow it for an upcoming show (I frequently loan out pieces; it gets them a chance to get out and meet other art, have a good time, a social life, all that. SELL them? Probably would…if someone asked, or if I weren’t completely lousy at marketing my own work.). So I took it down to pack it up.

The two side panels slid up and out of their brackets, no problem. But that center panel lifted right off the standoff, left it hanging on the wall and me with a bare unmounted panel in my hand. That work had survived the neighbors’ massive dynamiting of a cinderblock wall that literally knocked the paintings off MY walls… but apparently just touching it was enough to make the adhesive give up the ghost.

Why it never came off the wall in the middle of the night, I’ll never know. I think that panel is taunting me.

Anyway, I took it down to the studio to examine. The cutter had refired it on a roughish fiber paper, so perhaps where wasn’t enough contact between the standoff and the glass. I coldworked the standoff area, cleaned it really well and silaned it, then reapplied adhesive, attached the standoff, and let it cure for the required five days.

Then I packed it up and shipped it off to the gallery. At the reception, I noticed that the central panel was upside down. Sigh.

Thought about removing the standoff and rehanging it, but I have a feeling that panel is trying to tell me something, so I’ve just left it this way.

2016-05-15T15:35:28+00:00

3 Comments

  1. sunny strapp June 7, 2010 at 3:26 pm - Reply

    Thanks for the (re)views.
    From my side:
    The Gas: The kiln has no fire brick, and so would heat to 800ºC in twenty minutes if I let it rip. No need for that usually. And when its up there at temp, if something happens that cuts the gas supply (or the electricity) then its down to 250ºC in about 40 minutes. It is a great way to drop the temp thru the 700’s zone if you are not having much luck with handling devit. problems. The microprocessor has 16 steps and you can control just about anything you desire (except patience for opening the kiln). Going up, down or zigzagging as Rich LaLonde suggested. I listened to Dan Sch. talk about the whole thing and it seems that you can control IT all so well and have the heat so (in theory) even that “its all just that simple…” Seems like all ya need to do is have heating coming from everywhere at the same time and all equidistant and nonequivocal etc. And be brother in law with the fairy godmother would help too.

    The gas chambers radiate infrared and heat the glass from the top only. Has nice even heat (if ya believe that) on the surface of your glass. Everything that is in a shadow – like all those uncut layers – just heat on the edges until the heat makes it down in from the top. Can need compensations and two step tangos to get up to temp with no explosions, but I have that phase behind me (knock on wood).

    For slumping it has its up and down too. I can slump a whole sheet of glass to make some pretty bizarre lamps which have somehow found a market slot. But there have been some dropouts that could have done better with side heat too.

    Casting in open face is great I guess, but casting from above into a form needs more heat than I was giving it, and haven’t enjoyed too much success as yet in that corner. But the inspiration is back and so who knows what will happen next.

    My kiln inside is 105 cm long by 65 cm deep and 70 cm high. Whoa: That is high. I love it. Has the elbow and knee room that sometimes can’t be done away with.

    About the bowed panel pieces. I have come to love them and the challenge that they present when mounting in a window sash or frame. I have found that 8 to 10 tubes of translucent silicon are a rather nice artful filler and you can convince the customer that is the MODERN way to do it. If they are really liberal, there is a nice Bordeaux wine red silicon with just a slight slash of Burtons Tea Rose tint that you can surely convince them that THIS is the best color for those throw cushions on the sofa, to make a nice color match, of course. Ah yes,… those dear bowed glass panels.

    ss

  2. Cynthia June 7, 2010 at 9:48 am - Reply

    Hi, Sunny. Yes, Richard LaLonde suggested that to me long ago for a transom window I was doing. The idea is that the glass will cool and contract faster on the air side (since the kilnshelf is insulated) and therefore is liable to pull up at the ends into a mild curve, then freeze in that position. The relax cycle is essentially a slight reheat to even things out. And I still use it for long, narrow fused pieces when I do them. I have experimented a bit and it seems as if a shapes that have a proportion of about 3:1 or greater exhibit the tendency to bow.

    I talked about it in another post, http://www.morganica.com/bloggery/2006/glasswork/fusingtack-fusing/transom-window/

    On firing with gas: I saw it done in France, for long castings, but primarily because the people I was working with were ceramic artists who couldn’t afford another kiln. They were planning to switch to electric as soon as they could.

    So…I’ve always thought you used electric because gas wouldn’t give you the computer control you needed…seems like your experience is the opposite? Are you using a digital controller?

  3. sunny strapp June 6, 2010 at 1:10 am - Reply

    Hi C, I’m slowly wandering thru everything posted here and picked up this tidbit that I was unaware of: “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”

    Whats your source for this neat tango two step? Do you still employ this as a really useful addition in your kiln cycle?

    I suppose you are firing with electricity. Do you really have that much control in an electric kiln? I’m using propane and can control pretty much “instant” temperature changes and so I’m interested in knowing if this really gives a noticeable advantage, or is kinda like “crossing your fingers and standing on one foot” to prevent bowing and cracking. Ya know?

    thanks, and again, great stuff!

    ss

Comments welcome! (thanks)

%d bloggers like this: