I opened the kiln to some seriously cool pieces tonight. They may get beyond the level of five-finger exercise and into “worth exploring.”
Played around with the stringer-on-a-support-structure thing a couple of weeks ago, and built a small blue basket to test the concept. I liked the way it turned out:
I decided to explore this a bit, continuing with what I’m calling the keystone project–figure out just how far I can build self-supporting glass structures that can be tack-fused in a mold.
These stringer baskets rest on an infrastructure of glass noodles. There are short and long stringers–the short stringers help hold up the noodles, the noodles help hold up the long stringers. Everything’s superglued together during construction, but the pieces balance against each other once the glue burns off. I try to construct the thing so that all the load transfers to the center base; that way, gravity helps me out instead of working against me.
I start from the center of the mold (here, it’s Bullseye’s 8724 flared bowl) and work my way out, gluing segments of “noodles” together in a spiral. Here I’m using Uroboros Golden Amber noodles for the support structure–they’re ultrathin, extremely useful glass strips, much thinner than I could probably cut reliably. Big timesaver.
(And yeah, it’s time to rescrape the kilnwash from the mold, but I figured I could get one more use out of it by patching the nicked spots with new kilnwash–hence the pink splotches.)
As the support structure progresses (it’s about half done in the picture above), I start in with thick Bullseye stringer. In this one, it’s clear stringer. I’ve built up the noodles so that some segments are against the mold, some are stacked on top of the noodles, leaving gaps between noodle and mold. I start weaving short segments of thick clear stringer under and over these gaps; the idea is to “lock” the amber segments in place between the thick stringers, supported by later layers of thin stringer, once the glass softens.
Once the thick stringers are in place, I start laying in the thin clear stringers. In this bowl (about 16 inches across, 3.5 inches deep), it takes a LOT of stringer. They’re going to flop, pull in together and in effect shrink, removing all the air between them; making a 3/16 inch thick piece takes about 3/4 inch of stacked stringer.
I added some Spring Green and Aquamarine Blue stringer, not much, for interest, and also added some dichroic-coated clear stringer for the sparkle. Cooked it low and slow, and this is what the final looks like:
It’s a fast photo (apologies) but shows the shape and woven effect. It holds together well, but the lacy effect of the stringer makes it very fragile; you have to pick it up carefully (and NOT by the edges) to avoid breaking off pieces.
You can also see in the photo where the “locking stringers” didn’t hold, allowing the noodle segments to slide down the mold until they’re caught by another stringer.
Given the size and complexity, it’s a pretty good hold ratio, but I probably need to spend more time building up the support structure.
Still, this is a really fun technique. It ain’t cheap, but it’s sparkly, surprisingly close to a fiber basket in appearance, almost mesmerizing when you see it in person, and probably worth exploiting, if I can figure out how to stabilize the structure.
Really beautiful and unique! So you fired it right in the mold? No problem getting super glue on the mold either? What firing schedule did you use?
RC
Yes, it was arranged directly into the mold and fired to a mid-range tack-fuse, enough to really sinter the pieces together but not distort the stringer shape. The superglue burns off long before it would be a problem with the glass during firing. I wish I could tell you the schedule, but this post is about 10 years old and I’ve lost those records. More than likely, knowing how I do these, it was a fast ramp to about 1050F, hold for 30 minutes to settle the glass, then creep up to about 1200-1235F and hold until sintered. Then an amazingly long anneal–the piece is only about an eighth of an inch thick, if that, but it uses an annealing schedule closer to something 4-5 inches thick. You must give all those little joins and angles time to relax. Hope that helps.
One thing: I’ve had some of these sitting around the house for 15 years or more and they’ve stayed intact, but they are amazingly fragile. ONLY lift one by its base, never by the edges because I guarantee it will break off. The stringers simply aren’t strong enough to support the weight of the entire piece.
Great!
What a wonderful idea, and what beautiful results
chapeaux
Cynthia, these are stunning. Thanks for sharing your technique. Sheesh, I am learning so much from your blog and your generosity. Since I have to defer getting the Denver for a while, I am trying to learn more creative techniques I can use in my small kiln. These are sparking all kinds of ideas!
Dayle Ann