The Art of Etching Glass with Sand
What’s a story on etched glass doing in a carpentry magazine? Good question. I don’t know the exact answer. All I know is that every aspect of construction interests me, and when I met Donna Burrows and visited her studio, I knew that other readers would be interested in seeing what I saw. Maybe it’s something about craftsmanship.
Donna is an both a craftsperson and an artist. You can tell by the way she moves her hands—quick, sure, continuous strokes with a razor knife following lines I barely see; and what she does with a sandblasting nozzle…well, watch the video at the end of this article and you’ll know what I mean.
But it’s what she sees before one grain of sand touches the glass that makes her an artist—each layer of the finished piece, the same way a roof cutter or a stair builder visualizes a finished product when they’re looking at nothing but air.
Parrots for Privacy
Donna is the type that excelled in art classes and made the rest of us feel clumsy and useless. She’s been working glass for more than twenty years. I followed her through one job, from the client meeting through conception and completion. Her customers had recently removed a tree that provided privacy from their neighbors, but which also blocked their view. They wanted a partially-etched glass panel to put both their neighbors and themselves at ease. They weren’t really sure what kind of design they wanted, but they were fond of parrots.
|These folks were fond of parrots. They had a collection of life-size sculptures in the trees of their yard, and glass parrots inside their home.
Drawing and tracing
Donna begins each project with a conceptual drawing. On some projects she’ll spend days on the drawing.
Transferring the drawing is a simple matter of tracing over the back of the paper with a soft-lead pencil, which won’t tear the paper but transfers the lines to the vinyl. Donna lifts the paper frequently, checking that the tracing is complete, with each line crisp and clear.
Sandblasting is an art, especially creating a three-dimensional image from a two-dimensional drawing. Each layer must be blasted in precise order, so that each overlapping line creates the impression of three dimensions.
Donna starts by marking the drawing in layers. Parts of the drawing must overlap other parts—some leaves, limbs, and feathers must lie behind other leaves, limbs, and feathers. The lower leaves will be shot by the first blast of sand. To keep the layers straight in her mind, Donna marks each first-blast detail with an X, then follows the traced lines with an X-Acto knife.
She changes blades frequently—the vinyl dulls the blades fast. What would take most of us hours, Donna does in minutes—handling the blade with practiced skill. Rather than twisting her wrist, she twists the knife in her fingers—her hand operating like a CNC machine—and follows the tracing without straying from the lines more than 1/32 in. Before moving the glass to the spray booth, she removes the first layer of vinyl.
While it seems like a contradiction, in Donna’s hands, a sandblasting “siphon” gun is a delicate tool. She uses it for shaded glass, and for etching and shading on delicate areas of carved-glass designs. There’s a big difference between shaded glass, etched glass, and carved glass.
For shading, you don’t hit the glass straight-on with the gun, and you don’t just pull on the trigger like driving a hammer drill. If you don’t handle the gun with care, you can’t control the effect of the sand. It takes a lot of practice, but eventually you learn to blend the blast using a swiping-technique, hitting the glass from an angle, with 10 lbs. of pressure for small delicate areas and up to 40 lbs. for bigger areas. Like we feather the trigger on an impact driver, Donna feathers the trigger to adjust the blasting pressure.
When Donna carves glass with the siphon gun, she increases the pressure to 60 lbs., but that tool is for delicate work. For deep carving, Donna switches to a pressure pot system, holding from 100 to 300 lbs. of sand, run at about 80 lbs. of pressure, with a straight nozzle, just like a fireman’s hose, without any trigger. Controlling that beast takes real talent.
“You have to dance with it,” Donna says, “like T’ai Chi. You have to keep the flow going without stopping, without hesitating, without hitting one area too much. I’m only allowed to cut tempered glass up to 1/8 in. deep, and a lot of my work is on tempered glass because my panels are installed in doors, sidelights, and in large windows that come within 18 in. of the floor. But with annealed glass, I can cut as deep as I want…well, almost. For a 3/4-in. table top, there’s no code. To really carve glass, including tempered glass, there’s no better tool for the job.”
“The sand I use is similar to sandpaper. You could use 80 grit or 60 grit, but that’s like cutting a corner. You need to go slow and control the sand, otherwise the result is not pretty. You want a beautiful, fine finish.”
For the first blast, while hitting the edges, Donna moves the gun in to within 4 in. of the glass, but sweeps out as much as 16 in. to the point where she’s barely blasting the glass at all because of the distance between the gun and the glass.
|Once the first “layer” is blasted, Donna removes the next “overlapping” layer. The lines created by each layer quickly develop into a two-dimensional work.
With parrots on the windowsill, the finished etching fits perfectly in the clients’ home, providing just enough privacy from the neighbors without blocking the view.