That was me last weekend. I finally carved out a whole glorious 48 hours to make art. Excellent time to shovel out the studio, fire a bunch of pate de verre test tiles, mix up a couple of custom billets, redefine some investment facecoats, repair the broken head of the gigantic nude on my sculpture stand so I can get her silicone finished, burn off the new kilnshelf, develop a billet stack order for the recast of Repose, work through a hotcast sequence for Totem II and line up a hotshop to do it in, design that lighted steel stand for Riverflow’s next appearance, pour a couple of wax sheets…
The heck with it. Let’s PLAY!
And I did. I grabbed some clear sheet glass, buncha scrap glass and frit and noodles, put the shelves back in the kiln, and started playing. As much as I love sculpting and casting, it can get pretty tedious. It was nice to start and finish a piece of glass (multiple pieces, actually) in a day or two instead of a month.
And I didn’t feel a bit guilty, either. The stacks and stacks of old fused work I had hanging around the house have pretty much disappeared to gifts and sales, so I needed to make more anyway. I started with a couple of what I call samplers, kinda my idea of a glass quilt.
The samplers, AKA “glass quilts,” started as a fast way to zero in on tackfuse annealing schedules, but I liked them so much I started making them for their own sake.
Tackfused glass (i.e., where the glass components are only partly melted into each other) is essentially a bunch of separate pieces of glass joined at strategic points. It will try to contract away from those points during cooling, which can introduce a lot of stress if you don’t give the glass enough annealing time to relax. A tackfuse schedule can be three or four times longer than a schedule for a flat fuse. (And every so often the design can be so challenging that it’s simply too hard to anneal in a standard fusing kiln)
The best way to figure out how long to anneal a tackfuse is to test it, so I built a clear grid out of scrap glass, loaded it with different tackfuse ideas, and fired it. Then I flipped it over (to examine it for stress from the smooth, clear back) and stuck it under the polariscope. I noted which designs exhibited stress halos and re-annealed with a longer schedule, repeating the process until all the stress was gone.
I liked the looks of the test piece, so I stuck it on the wall and started making samplers just for pretty (above). The colors and sparkles are inviting, they attract a lot of attention at demos and lectures, and most people (especially children) wind up petting all that texture.
They’re also easy to make if you don’t rush it; when I did a lot of fusing I generally had at least one in the studio, constantly. Whenever I had leftover glass, or some spare murrinis or simply an idea, I’d fill in a couple of cells, then put it back up. Once I’d filled the last cell, I’d tuck it into a spare tackfuse firing, pull it out and give it to someone. Then I’d start another.
So…to make one, you need some clear glass scrap and a bunch of compatible scrap or frit or whatever. I like thin BE Crystal Clear sheet–it’s a little sparklier and the thin glass base isn’t as bulky as 3mm sheet in the final piece–but use whatever you have on hand. I cut out the largest shape I can manage in the scrap, then grind the edges with a diamond pad (I take it to 200-grit) and slightly round off the corners. (Since this will only be tack-fused, the edges can sometimes stay sharp in the final piece. If you round them over now, they’ll gloss up.)
I lay the blank sheet on the light table and mark out a regular grid of even squares with a ruler and a Sharpie pen. Then I start choosing the layup for my “cells.” (In the photo at left I’ve laid my glass on a clear acrylic turntable–it lets me rotate the work without preventing light from getting through. It’s about $5 from TAP Plastics.)
I cut quarter-inch or 3/8 inch strips of 3mm glass and edge each cell with them, tacking them down with superglue. If your cutting doesn’t produce square edges, you can save yourself a LOT of time and frustration by grinding one long edge of your strips flat.
You can do it by hand, but if you can zip them through a flat lap grinder, belt sander, bench grinder, etc., your body will be grateful.
3mm strips will stand on their own with enough area to hold superglue well, so they’re fast and easy. But if you’d rather have thinner borders you can use Uroboros noodles or Bullseye’s dichro Sizzle Strips, or strips of thin glass. Just be aware that you’ll probably need to devise some sort of support system to prop them up during firing.
I had some scrap charcoal sheet, so I used that–the darker edge makes a nice stained glass-like border. I’ve also done this with plain old black glass rod and it’s lovely (if a bit thick). It’s also fun to cut black irid squares for the corners, then run strips of black rod from square to square (above) for a somewhat fancier look.
A perfectly symmetrical grid is boring (to me), so I leave out some cell walls. And I’ll divide others with additional strips at different angles. Here I’ve superglued my favorite black noodles on diagonals within a cell. The noodles are about half the height of the cell walls, which is better if you plan to fill the cell with powders.
Once your cells are complete you can fill them with just about anything, as long as it’s compatible with your base glass. I’ve used coarse frit (you can add tiny shards of dichroic scrap for subtle sparkle), homemade murrini, packed powder (use tongue depressors and palette knifes to mound and press it into geometric shapes), shaped stringer, intricate waterjet cuts leftover from other projects, small cast faces, metal foils, frit balls–all kinds of things.
It’s best to fill most of the cells to the top of the wall or higher; if you don’t want to waste cell components you can cut a sheet of clear scrap or use clear frit in the bottom of the cell as filler.
That works especially well if you want to line the cell floor with a layer of gold, silver or palladium foil, as in the example on the right.
Caution: Fine, medium and powdered frits will fire darker than in the jar, so keep that in mind when you’re composing.
It helps to keep a color chart around so you’ll know that the pale blue powder you’re loading into a cell is really navy blue and can plan accordingly.
Powders, especially, will shrink quite a bit; the yellows and red, left, were originally full to the brim. They’ve lost roughly half their volume, so much that they’ve exposed the clear glass beneath and there’s nothing to support the walls, which have flopped over.
You control the final appearance of the piece through the firing schedule–you can fuse it completely flat, for example (if you want sharp lines build your composition from the bottom up, fire, then flip it over and use the underside as your new “top”).
These are really meant to be dimensional tackfuses, though, mostly keeping the original glass shapes safely rounded but intact. Depending on the level of heatwork you give the work (and the glass you’re using), you’ll get everything from glossy, smooth shapes to sharp, sparkling crystals.
Exactly how much heatwork you’ll need depends on your kiln and also the glass; many black glasses, for example, are nearly melted at temperatures that barely soften white glasses. In the picture above left, four colors of glass powder gave textures ranging from sandy (center) to almost completely fused (top).
Remember again, though, that the tackfuses that leave your angles sharp and sparkly will also require the longest annealing schedules. You’ll want to find the maximum thickness of your composition and anneal for anywhere from two to four times the recommended schedule for a flat fuse.
Either way, you’ll want to dam the edges to keep the border walls from flopping over, which looks sloppy. If you fill cells with frit, be prepared for it to contract away from your cell walls, which can also cause some wobbly lines.
For these particular samplers, I used the following schedule (schedule is given in degrees Fahrenheit, “dph” means degrees per hour):
WARNING: This is the schedule that works in MY kiln (actually in only one of my kilns–I use a different schedule in other kilns). I’ve included it only to give you a general idea of how to set up a tackfuse. You will almost certainly need to alter the schedule in your own kiln.
- 200dph to 1000, no hold
- 50dph to 1240, hold 20 minutes (tackfuse processing)
- 50dph to 1300, hold 5 minutes (glosses and softens sharp angles)
- AFAP to 900, hold 4 hours (extra-slow anneal for tack-fused stress relief)
- 30dph to 800, no hold
- 60dph to 700, no hold
- OFF (after 700 degrees, my kiln freefalls slower than 80 dph, so there’s no need to waste power)
In my kiln, that schedule will fuse the components pictured at the top of the page to this level: