Rowan -

Unfortunately, I don't break enough windows to keep my glass stock up to date very well. Most of my current remnants probably come from picture frames, but they're pretty much the same. I just use a cheap "glass cutter" - wheel type - to score a small piece, twist to snap it off, and then drag it across the wood. It cuts quite cleanly, in small even amounts, without lifting the grain adjacent to the cut.

I've got a set of steel "luthiery scrapers" with modified shapes for gouging out shapes, and they're a little handier for some convex shaping; but they're not nearly as much fun to use (i.e. don't work as well) as fresh glass - when you've got a big enough piece of glass to get the shape right for the task.

Chuppa:

They used to advertise "the sharpest knives you can buy." They weren't, although they were good enough to use out of the box.

(Of course I sharpen X-Acto blades before using them too.)

The Chuppa knives will take a pretty good edge, and retain the edge reasonably well. The blades seem to be a little harder than I really prefer, which makes it more work to get the edge you'd really like.

The cast-on aluminum handles are of course pretty much indestructible. I have one Chuppa inherited from my mother that probably was new in about 1943 (a free-gimme from the corner grocery), and they've changed very little. The paring knife seems to get a slightly larger handle now, and some of the larger ones - the last I picked up - have a bit "flatter" grip.

One of the "weak points" with Chuppa was a very limited selection of sizes and shapes, at least as shown on the web site they had a few years ago. It would be interesting to hear if their new catalog has expanded the selection, although I'm pretty well stocked with what I need (and some I don't really need) right now.

John