Tools: Cropping templates

Sometimes removing all the extraneous junk from a composition makes it easy to see. All it takes is a piece of cardboard and an Xacto knife.

Photographers and art directors in pre-Photoshop days would figure out how to crop a photo by setting it on a lightbox and covering up the edges with paper/cardboard/whatever. I was fascinated by it; a half-inch of concealment could turn a bad photo into a great image.

Why not apply the same technique to glass?

I do that when I’m working with flat part sheets I want to cut up and turn into pendants, or components in a larger work. Since glass STILL doesn’t come with an undo button (Bullseye, you need to get on that right away), it’s a fast way to see what you’re going to get before the cutter touches the glass. In the example above, I’m doing it with frit-sandwiched glass sheets.

It ain’t exactly rocketscience: Get a sheet of cardboard (or, if you want permanent template, masonite or wallboard). Draw the shapes you need, get an Xacto knife and cut them out.

All you have to do now is position your homemade template on the glass, and move it around until something strikes your fancy. Then outline the window with a Sharpie marker, and make your cuts. Voila.

This is also a nice way to quickly sketch shapes when you need a LOT of cutouts, although for that you may want to make your template in clear vinyl. It makes it easier to see where you’ve been.

Tools: Worktable clean-up brush

Worktable clean-up brush

Long ago I took a drafting class, bought all the required supplies and, at the end, wondered why the heck anyone in their right mind would draw all that stuff by hand when a computer and a little CAD software could do a much better job, without a lot of erasing and redrawing and Rapidograph pen clogging.

Turns out the best reason to take a drafting class is that almost every one of those supplies can be put to much better use in a glass studio. For example, the drafting table brush shown here, originally designed to keep eraser crumbs from dimpling your vellum, is a great way to marshal your glass scrap.

These little guys are still around at art and architectural supply stores, don’t cost much, and work better at sweeping up ALL the shards than any brush I’ve so far encountered. (A damp paper towel works, too, but doesn’t last nearly as long).

Disclaimer: I doubt I invented any of this; some is pretty obvious and the rest probably originated in Mesopotamia or something. If you know of an even smarter tool, please, please share!


Tools: Reactivity charting

I’ve mentioned this before: Before you go combining frits, it’s a good idea to understand what reacts with which.

The linked post explains it in more detail, but in general: When a warm glass meets up with a cool glass, be careful. Cool glasses often contain copper. Warm glasses frequently contain sulfur or lead. Wherever the two touch those chemicals will combine to form a third, which is frequently some shade of brown, grey or black.

Continue reading Tools: Reactivity charting

Methods: Cutting stringer

When cutting stringer, remember: There’s safety in numbers.

Don’t ask me why, but I have better accuracy when cutting several stringers at once than I do trying to chop one up evenly. I think it works because I stop thinking about cutting one angel-hair-pasta-thin bit of glass and simply score the way I always do. Continue reading Methods: Cutting stringer

Methods: Frit volume

The first time I packed frit into a mold I learned the difference between the volume of frit and the FIRED volume of frit–the level of shrinkage can be disconcerting. Fill up a test mold to the brim with powder, tamp it down tightly so that it looks like this:

And it comes out of the kiln looking like this, a bit less than half of the original volume:

Blame it on air. Literally.

What’s happening is pretty basic: The smaller the particle of glass, the more particles you can pack into a volume, the more gaps you have between those particles, and so the more air. Fire the frit and some of the air is trapped in the resulting glass, making bubbles. Most of it, though, is squeezed out as the glass softens, leaving you with mostly glass instead of glass+air.

Without all the air, the total volume decreases, sometimes significantly. Unfired, a solid, bubble-free chunk of glass will always take up a lot less volume than its gritty cousins. Below, I’ve weighed out 1.5 ounces (about 43 grams) of glass in everything from glass powder to billet. Look at the difference in volume:

The powder takes up about three-quarters of the cup, while the billet barely splashes the bottom.

Moral of the story? For best results, measure frit by weight, not volume.

When I want frit to cover an area completely, to a precise depth, I cut a sheet of scrap glass to the right size, set it in place to make sure it fits, then weigh it. I weigh out an equivalent amount of frit–that much needs to be packed into that space to achieve the thickness I need.

Or I do it without the glass: Measure the area, take its volume (LxWxH) and multiply it by the specific gravity of the glass (2.5). For example, if you want to fill a space 5 cm long by 7.5cm wide by .6cm deep (about 2 x 3 x 0.25 inches):

Volume: 5 x 7.5 x 0.6 = 22.5 cubic cm
Weight of glass: 22.5 x 2.5 = 56.25 grams of glass
(or about 2 ounces of glass)

I use the metric system because it’s a bit more precise when dealing with small amounts. But either method works consistently well for me.


Tools: Layup elevators (i.e., cups)

There’s nothing worse than spending hours on some fiddly, gazillion-piece layup (like this one) and then knocking it all cattywampus because you can’t get a finger under the edge to move it to the kiln. At Bullseye they taught me to raise work up on small plastic cups so that I could gently lift it without jarring anything.

I take that one step further at home (partly because I have a devil of a time finding those little plastic cups). When I’ve finished with a layup, I rest it on small paper cups about twice the height of the ones used at Bullseye. Turns out it also keeps the work intact and out of my way on the work table while it’s waiting to go into the kiln. (I used to stage finished layups on the laundry room counter, which is now serving as a playground for my two furry miscreants. I made the mistake of putting a glass layup on that counter once–just once–and I’m still finding shards.)

Normally I set the cups facing down, as in the photo above. If I’ve got components–frit, fiddly little pieces, etc.–that need to be added after the layup is positioned in the kiln, I flip one of the cups up and store them in there. That’s a lot more convenient than getting out to the kiln and realizing you’ve forgotten part of the piece, or trying to juggle glass, components, doorknob and garage-seeking cat at the same time.

If you know of an even smarter tool, please, please share!

Tools: Shelf scraper

Ever seen people scraping big ol’ kiln shelves and bowls with a ¬†teensy-weensy little palette knife, scrub brush, kitchen spoon, scrubby or steel wool?

I have. Frequently. A big drywall knife will make your life MUCH easier.

Drywall guys know that the fastest way to smooth, seamless walls is to match the knife width to just slightly bigger than the seam they need to make with joint compound. Same thing with kiln shelves; the fewer strokes it takes to clean off a shelf, the less work you’re doing, the less you’re exposed to all that dust, and the less likely that you’ll miss spots that show up later, in your glass.

I have an 10-inch knife, above, with a very thin blade. It can scrape off a 22-inch square shelf in about 10 strokes, and because the blade is so thin it can really get under the coating and lift it off.

They’re formally called “taping knives,” and the one I have cost $8.50. Well worth it. I have a 2-inch knife for scraping molds.


Methods: Embedding frit in frit

Next time you visit a kitchen store (a restaurant supply is even better), look around with your studio in mind. I found these cutters on the closeout table and paid maybe $8 for the lot. They’re typically used to cut aspic, jellies and small pastries, and they’re great for tracing shapes and forming clay. But they’re really, really, excellent for embedding frit in frit (below). Continue reading Methods: Embedding frit in frit

Storage: Glass ID tips

I am NOT one of those people who breezes into Bullseye saying, “I’d like two sheets of 1125-30, a jar of 1823-08 and four 1101-0576es.” Nope. To me those things will always be 3mm orange sheet glass, Burnt Scarlet Striker powder and clear glass rods. Nor can I distinguish it on sight except in REALLY obvious cases.

Which is fine…as long as I don’t cut off the part with the label. The first time I discovered that the supposedly French vanilla sheet I’d fired into a large strip bowl was actually lavender-grey (left), I stopped relying on my visual memory and started labeling the bloody glass the minute I got home from the glass store. It’s a great habit to get into and fairly easy if you keep it up.

First, even if the glass has the original labels, I write the color name on the glass in great big Sharpie marker. That way the corner I’m most likely to grab has a big, clear label on it (as above).

I also label my scrap religiously; I love colors like Marigold and Gold Purple, and it’s amazing how much they look like non-striking colors when you’re flipping through the scrap bin.

I frequently work with experimental glasses (one of the advantages of living near Bullseye) that aren’t in the catalog, and sometimes even the Bullseye folks can’t remember exactly what the glass looks after firing. For those, I cut off a small corner of the sheet and stick it in any available space for the next full-fuse firing. Then I tape the piece to the sheet for instant color identification.

I used to write the color name directly on the glass rod with a Sharpie, but there’s not much writing space there and it tends to wear off on your hand. Now I keep a roll of masking tape on hand, and slap about an inch onto the rod, tape it together, and write the ID on my home-made tag.

It helps; since I got religious about labeling I’ve never had a surprise tweed bowl.

Disclaimer: I doubt I invented any of this; some is pretty obvious and the rest probably originated in Mesopotamia or something. If you know of a better way, please, please share!


Methods: Reaction outlines (and quilt basting spray)

I got hung up on making Bullseye-compatible “murrini” awhile back and started hunting up ways to add tiny detail, i.e., smaller than the average profile of a sheet of glass and repeatable.¬†(and yes, I’m really, really aware that there’s a big difference between what I’m doing and what a skilled lampworker like Greg Chase does).

I talk about some of them in my murrini posts, but one of my favorite was the simplest: You get a big impact simply by stuffing two reactive glasses into a small space like a murrini mold. Surround a compatible glass rod with glasspowder it reacts to, for example, and you’ll get a beautiful, softly organic reaction line separating the two, almost like cartoon outlines. In the picture above, I’m getting it by playing around with sulfur and copper glasses together.

Sometimes, though, I need the same kind of line between two glasses that don’t react to each other. That takes a little more work…along with quilt basting spray.

Continue reading Methods: Reaction outlines (and quilt basting spray)