Using up (lots of) scrap glass

>>>>Using up (lots of) scrap glass

fivefingeropenThis getting ready to move stuff is a pain but with some compensations; I inventoried my raw glass stock (came up with about 90 sheets of glass that will be coming to a garage sale soon), and my fingers started itching to cut glass.

Seems like ages since I’ve laid cutter to glass, or chonked a piece off a glass rod. And there was all that lovely scrap that I don’t want to move.

Some of it will be given to school and community center projects, but there was a bunch of nearly useless skinny pieces…so I banged out some keystone projects.

Nothing great, certainly not great art, but a nice change of pace from the intensity of casting and a nice way to turn a bunch of scrap into something that holds fruit.

fivefingercreamsHad a whole bunch of strip-cut white glass and small scrap, so I laid it into a big bowl mold, added a ribbon of red/orange/yellow cut rod pieces for accent.

This is a relatively easy project. The hard part, of course, is cutting and building up all those strips.

Fortunately, precision has nothing to do with it; I like the look of rough strips tackfused together. And since this is laid directly in the mold, from the bottom center heading up and out, it needs smaller pieces that can be interwoven to fit the corners and curves.

ribbon1That means I can use up even tiny pieces of scrap. I built the ribbon of cut rod first (judiciously superglued in spots to keep it in place), then piled up my white/cream scrap and started cutting.

I didn’t have enough of any one neutral to do the whole bowl (this mold is about 16 inches across and maybe 3 inches high), so I used them all. That meant I needed to mix things up a bit, to ensure that colors were evenly distributed.

ribbon2Since some of these were strikers (and, in fact, there were a couple of Salmon Pinks in there I hadn’t really counted on–good lesson in correctly separating your scrap) I kinda had to take the colors on faith.

I cut the pieces small enough to conform to the mold’s contours (and although I did clean the pieces, I wasn’t all that fussy about getting the magic marker off, as you can see), then I stacked them into the mold, resting them first on the ribbon, then on the bottom of the mold.

During firing, gravity would slide the pieces down to the bottom of the mold and they’d lock together; I slid thin strips into the gaps made by two rods to ensure locking.

ribbon3I’ve found there’s a trick to getting the strips to go around corners; you need to provide enough surface area for a good tack-fuse to make the bowl hold together. As above, I did that by weaving pieces together and interlocking the verticals against the horizontals.

There are a LOT of pieces of glass in this thing, but it’s soothing work if you’ve got good music or a movie going. And it also lends itself to some cool closeup photography:

Did a couple others I’m not quite done with yet, but this one’s pretty much ready to go and the style has all kinds of possibilities. If you’ve got a bunch of scrap, it’s a fun project to try.

ribbon4ADDENDUM: This is NOT your average flat-fuse. It’s a tackfuse, which means it remains a collection of somewhat fused but separate pieces of glass. That, in turn, means you’ve got a lot of potential stress points that need time to relax.

This piece is a half-inch (12mm) thick at its thickest point. That isn’t nearly enough for a tack-fuse with this many stress points, so I started with an annealing schedule for a piece nominally 3 times as thick, or 1.5 inches.

Yes, you’re going to spend a lot more time waiting for the kiln to finish, but look at it this way: It’s a lot quicker than having to rebuild all those daggone strips…

I played around with strip tests until I came up with a modified schedule that gave the glass more time to relax but slightly accelerated the cooldown.

The schedule’s below, with the usual “your mileage may vary” warnings. Remember, since this is a tackfuse, your mileage will REALLY vary depending on kiln position, glass colors you use, whether or not you include the rod pieces (they’re probably the most vulnerable part of this layup).

Please, please, PLEASE do some test runs to develop your own schedules and save yourself some king-sized heartaches.

Schedule is in Fahrenheit:

  • 200dph to 1100, no hold
  • 75 dph to 1240, no hold (most of the slump/tack happens here)
  • 50dph to 1300, hold 10 minutes (solidifies the joins, finishes edges)
  • AFAP to 960, hold 8 hours
  • 20dph to 800, no hold
  • 40dph to 700, no hold
  • 80dph to room temp, OFF


  1. Tom Carter May 10, 2016 at 9:58 pm - Reply

    Morganica is there another site or something ? I only get a few photos, sometimes none at all anymore. Am I in an older site?

    • cynthia May 12, 2016 at 9:42 am - Reply

      I’m sorry, Tom; I’m in the midst of changing website hosts, and something has really gotten messed up, image-wise. So far the only solution anyone has that won’t kill a lot of work is for me to go in and literally rebuild each post (there are about 750 affected). So I’m working on it… sigh.

  2. Cheryl Thompson March 18, 2014 at 11:53 am - Reply

    Thank you so much for this creative art piece you have shared with those of us that are glass alcoholics. I have so much scrap glass from not just myself but from my students as well. I am hoping to get some of them to do this and help clear out some of this scrap that I just can’t throw away.
    Thank You,
    Cheryl Thompson
    Art Glass City

  3. Kathy September 10, 2011 at 2:21 pm - Reply

    This is a beautiful piece of work. Thank you so much for sharing. For a beginner it is great to get inspiration from talented artists.

  4. cynthia January 16, 2010 at 11:01 am - Reply

    Hi, Havi. Thanks for all the compliments! The bowl was a present for my mother; right now it’s sitting in my parents’ living room. On your questions:

    1. I’ve shifted Bullseye schedules down to 900 no matter what I’m doing, so if I were firing this today I’d probably change the anneal soak to 900.
    2. Well, the mold is well-kilnwashed and this is only a tackfuse, so it won’t flow against the mold as much to begin with. It just barely takes on the shape of the mold. The superglue does stick to the kilnwash (or anything else) but it’s going to burn off and free the glass well before fusing temperatures. I do have to be careful not to scratch the kilnwash off the mold, but that’s easy.
    3. This technique relies on gravity to keep the glass in place while it’s tack-fusing together, so the pieces must be stable when they’re assembled. Usually they’ll slide together a bit and compact, but otherwise they are the same shape going into the mold as coming out. As long as the pieces would stay in position without glue, any mold would work for this technique.

  5. haviva zemach January 16, 2010 at 8:06 am - Reply

    Hello Cynthia
    I just discovered your so- wonderful- bowl , I LOVE it. I love so much the uneven lines and what becomes of them.
    Do want me to repeat what had been said about you above? That you are so talented, that your artistic skills in art – photography – writing are great.
    THat your sharing is beyond knowledge and generosity and kindenss, and I am so very grateful for that.
    Few questions though
    1. In view of the new annealing BE charts – would you still anneal at 960 or go down to 900? or maybe hale and half?
    2. How can you be absolutely sure that the piece will not stick to the mold? I’d be scared like hell to do so…………..
    3. Do you think that this tachnique is applicable to other forms of bowls? Like ball ahped bowl, for example?

    Thank you SO MUCH for the inspiration,

  6. Espace VERRE September 15, 2009 at 10:24 am - Reply

    I wanted to send you the information for the 2010 GAAC Conference that we will be hosting in Montreal. For more information, please visit our website.

  7. Ellen Buskirk March 11, 2009 at 2:07 pm - Reply

    What a lovely piece! I really appreciate your sharing time and talent with the rest of us. Your answers to questions on WGBB are so valuable and the inclusion of a link to a piece that you have documented is a real bonus. Your talents (art, glass, photography, writing) are immense and an inspiration.
    Good luck with your move. I hope you will still be near BE!

  8. cynthia March 6, 2009 at 10:30 pm - Reply

    Hey, Tam, and welcome! Love to meet you at BeCON, but I’m hoping to be moved by then (famous last words). Thanks for the nice comments.

    On the Luminar–I like using it, but I’m not an expert. What I have learned is that success depends on what you’re doing with it. It’s great for fine, really detailed models, especially if they’re fairly small. The bigger the model is (I find) the harder it gets to manage.

    I do thin down the initial coat with water a bit, but not much–I can get it pretty thin just by whipping it with a hand-mixer. It does have trouble sticking to very smooth surfaces on the first coat. You just have to (patiently) keep brushing it in and brushing it in. There’ll be some on there even if it’s pretty thin–let that dry and then start your second coat.

    I’ve got to admit, no matter what investment mixes I try I wind up back with good old plaster/silica. It’s cheap, easy to modify, takes detail and comes off cleanly. So these days I mostly use p/s.

  9. Tam March 6, 2009 at 7:17 pm - Reply

    A glass garage sale! How cool. Can you have ot the weekend of the Bullesye B-con when I’m in Portland? I’ll drive to your sale!

    Thanks for the fabulous information on your blog. I’m trying to use the Luminar Mold but not having to much success. Ugh. I saw your recent post on The instructions with Luminar say to dilute it for the first coat but it tends to not stick or flake ?

    I’ll keep trying or go back to clay as a mold ~ Keep up the good work 🙂 Tam

  10. cynthia March 6, 2009 at 3:57 pm - Reply

    Kathleen, 8 hours is probably overkill–I haven’t tested this with clear on the polarizer (although it’d probably be gorgeous in clear, maybe with a line of pattern bar or some kind of really jazzed-up line of opaque something or other). You could probably get away with 6, but the way I set up the schedule it wasn’t going to be ready until morning anyway…

    Thanks for the nice words, Linda, much appreciated.

    Jeri, yup. Superglue. I oughta buy it by the case for stuff like this, and it DOES get on the mold. Generally I get the little tubes of liquid (not gel) superglue, as small as I can find them. They’re essentially one-use, so I don’t like wasting glue.

    I don’t superglue everything, just a few pieces. I usually set one piece against another, make sure it’s stable, then let a drop of glue slide into the joint; capillary action will draw it all the way in (that’s why you want it runny-the gel won’t suck in like that). It sets up almost immediately. The glue will burn off around 500-600F (or so I’m told) and since this is opaque glass any residue won’t be seen anyway. And there’s so much texture on the surface it probably wouldn’t matter much if there was a fingerprint in the glue.

    (And thanks for the kind words!)

  11. jeri Dearing March 6, 2009 at 2:47 pm - Reply

    Hi Cynthia,
    Thanks again for posting this beautiful piece. You also posted on Warm Glass to my questions. I was wondering when you say you used super glue on the cut rod pieces did you glue them while they were on the mold, actually getting the glue on the mold? I always get amazed at the things that will burn off when fired but a fingerprint can mess up a whole piece!
    Thanks again and I love your blog!

  12. Linda Dean March 6, 2009 at 2:15 pm - Reply

    I also wish I lived closer in order to attend your garage sale! I’ll be moving in 2 years, guess it’s never too early to start fiquring out how it can be done. Thanks for the project steps and schedule

  13. Kathleen Krucoff March 6, 2009 at 11:30 am - Reply

    Hey, thanks for the addendum and posting the fuse schedule you used. I was prepared for most of it except the 8 hours at 960! Yowser.

    I agree, the fun of opening the lid to the kiln is great. Love the awe moments and live with the oh no moments….learn from those! 😉

    Good thing the folks that do moves have strong backs…tough work. Last time we moved, I moved all of my glass myself. Now I have TONS more and shudder to think about it. Plan to stay where we are for quite a while…at least that’s our hope.

    Have a great weekend!

  14. cynthia March 6, 2009 at 8:04 am - Reply

    Thanks, Kathleen. It’s fun, and you learn how to unstick your fingers when they get superglued together. 😉 I like messing around with shapes that really can’t be slumped into position–it’d be hard to get the strips to flow around the mold shape this way unless you laid them up directly in the mold. And because it’s a tackfuse, pieces won’t fully strike and you’ll get some really cool color patterns.

    Curiously, I find it doesn’t really take LESS time to do it this way. A lot of times I’ll prefire the components to round them off, or get a “lip” on the edge that helps define stuff, and I usually need two or three attempts to figure out how things will work. But it’s fun to open the kiln–you never really know what’s gonna work or not.

    Yeah, except for a lonely sheet of dichro it’s all Bullseye glass. I don’t do much sheetwork anymore and the last time the movers shifted my studio they broke about half the glass and charged a small fortune for all the weight. So I figured this time I’d lighten the load–give the scrap to worthy causes, sell off a bunch of sheet and possibly some rod (pounds and pounds of it). The frit is sacred and all mine, so the movers will just have to groan.

  15. Kathleen Krucoff March 6, 2009 at 6:22 am - Reply

    WOW! Now this is great inspiration. Love it. I’ve been doing some bowls using strips, but doing the fully fused approach with a dam to keep them at the thickness Coldworking (which I feel like I’m coming up to speed on) and then slumping. Doing something like this is really, really cool. Thanks for sharing. I love the finished result.

    Wish I lived closer to see what glass you put in your garage sale. Although I really don’t need to add to my supply, but when you’re a ‘glass-a-holic’ like me…well it’s just hard to resist. I’m guessing since you use Bullseye you have a supply of COE 90? Just curious.

    Looking forward to seeing more pictures! Thanks Cynthia!

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