Instructables

How to round the edges of glass slices cut from wine bottles with a wet saw?

I would like to make glass rings of different sizes, and need to know how to round the glass slices I have cut from various bottles using a wet saw.  Karen Marie provided a wonderful instructable on how to cut the slices.  If they are put into a fusing kiln, the bottom will be flat, however, i would like them to be round.  Would a torch work, and if so, what kind and size. 

Re-design4 years ago
You can round the edges with sandpaper, but then the edges look frosted.
+1

Sand 'em with sandpaper increasing in "fineness" as you go along.  Best way imho.
You want to round over the cut edge, like the lip of a drinking glass?

You can use a regular propane plumber's torch with bottle glass, but you'll get better results with an oxy/propane, MAPP or oxy/mapp torch. All of these are available at Lowe's/Home Depot. You do not need a professional glassworking torch, but having one wouldn't hurt.

The real trick to torch-firing glass in this way is to heat very evenly to avoid thermal shock. I put cut bottles and rings on my pottery wheel and let them turn slowly while I fire them, which helps the pieces heat evenly all the way around. A record turntable or other motorized base would work just as well. Warm the pieces slowly with the torch, then focus on the cut edge until it beads over, then cool down slowly.

Even if you heat very evenly, you will still need to anneal the glass in a kiln to relieve the internal stresses after firing.

Cold-working the edges as steveastrouk suggests is also a good option, if you have the proper tools available.
Glass product makers use a range of special buffing wheels and belts from 3M

solutions.3m.com/wps/portal/3M/en_US/Manufacturing/Industry/Product-Catalog/Abrasives/
NachoMahma4 years ago
.  I've never done it to jewelry, but fire polishing works well for all sorts of cut laboratory glass.