Thanks for the links. The laser stuff looks interesting. I'm still wondering if I did the right thing in not ordering the rotary device for my laser. The one thing I laser etched into glass looks "ok". It doesn't look exactly like sandblasted etching.
Adrian
Nor will it ever. Two totally different things. The laser creates tiny fractures to simulate the look of sandblasting. Glass is a strange animal. It does things you won't believe until toy experience it. I had some engraving of text to do a couple of years ago. The glass pieces cost like $45 each, I engraved all the text and looked and there was one letter missing from a word. Huh? The Corel file was clearly correct, the job as show in the job control program for the laser clearly showed all the letters, but this one letter was completely missing. How the heck it happened baffled me. I did another one, a different letter was missing, same file. As I'm staring at the thing trying to figure out what the heck is going on, the letter magically, instantly appears. WTF???? Since that day, I've seen that happen many times, and I've video taped it as well just to make sure I wasn't crazy.
What happens is the glass is getting the micro fractures and you'll hit a spot that doesn't quite fracture cleanly, and as it cools down from the lasering, it will push it over the threshold and finally cause it to "crack" and it'll show up.
You also end up with tiny shards of glass as the end result because you're essentially just chipping the surface of the glass, where the sandblaster will eat the material away.
You can laser glass, it's tricky, it takes practice, and what works perfectly today might not work perfectly on the next piece of glass. It's that unpredictability that caused us to start sandblasting things. Not to mention the time. A logo on a pint glass might take 4-6 minutes on a laser. You can sandblast it in about 60 seconds, so it's considerably faster for larger batches. There's certainly time involved in printing the negative and making the mask, but once you get going, it's all very quick.
If it means anything (and it doesn't), we have a rotary for one of our lasers and we use it less than once a year. It's not worth the effort. However, your work might be different than ours and you might use it daily (which is why I said it doesn't mean anything.