I recently bought myself a dremel 4000 at the d&m tool show, and since having it have been playing around with the various attachments.One thing I decided to play with was glass engraving, using the flexible shaft and a diamond bit.
This is the result of my playing
My first attempt was this pint glass and a maker | geek engraved on it.
My second attempt was this wine glass
I'm pretty happy with it, it's not perfect, but it is pretty good and I think it came out better than the first attempt. In case you're wondering, the Chinese says 'wine' not terribly original I know. I thought about just engraving WINE in English, but thought it would be more interesting to attempt something in Chinese. Since I don't speak or read Chinese I figured that if I made a mess of it, it would show up less than it would with a badly engrave 'wine', at least to my eyes.
I have shown it to a Chinese colleague and he confirms it does say wine, and is legible, so that's a relief.
Ultimately though there was little doubt that the dremel would be able to engrave glass, the biggest concern being that I might be heavy handed and smash it accidentally. More interesting was the process I decided to try to make the engraving.
For the pint glass I followed a suggestion I found on line about simply printing off what you want to engrave, and popping the print out inside the glass, just let the part you want press up against the glass where you want to engrave, then just follow by eye. This was ok, and perhaps for something more abstract it would have been fine, but I felt it lacked a little for rendering something with this detail. The letters are a little more wavery than I wanted. It looks ok at a distance, but I realised I would want a better method for future attempts.
So I hit upon the idea of masking, much like you would when stenciling something, I decided to cover the area with electrical tape (it's quite thick) then stick the template onto of the tape. From here I then used a craft knife to slice the template out of the underlying tape, and then carefully lifted the cut sections away. This was a little tricky because if you didn't cut perfectly around then the stray places where it remained connected wanted to pull the template out of shape. It also meant my hands wound up covered with little pieces of sticky tape.
However after about 30 mins of careful cutting, I arrived at this:
From here I just needed to carefully engrave within the lines, since the tape is quite thick, even where I wobbled a little it resisted me just engraving into the glass and gave me a little room for error. I carefully worked my way around engraving in the lines, checking I'd got reasonably even engraving over the whole pattern, then peeled away the template to reveal the finished glass.
This worked MUCH better than attempting direct free hand, but was obviously commensurately more hassle to set up. just printing something and popping the paper in the glass is very fast. taping and carefully cutting out a template is really not fast. Though obviously that depends a little on the complexity of the pattern. I guess if you were engraving something with dense textures and patterns you would have to go with the through the glass technique, but for relatively simple shapes and lettering etc this seems like the way to go.
My next challenge is to try something a little more geometric, which will really show up if I can't get good clean edges