Step 4: Finishing the Edges

OK, this is tedious part of the process. Obviously you don't want to cut your mouth every time you use the glass so you have to smooth out the rim.

Professionals who do this for a living will "flame roll" the edges of the glass making them shiny and smooth like a standard glass. Unfortunately that requires specialized tools and you'll want to carefully anneal the glasses afterwards to minimize the chances of cracking and breaking.

** You cannot simply take a propane blow torch and get the edge smooth!  If you try it, it will simply crack the whole glass.   If you really want to do that, you'll likely need a glass worker's torch (usually Oxygen/Propane).

Using a Dremel tool, I first rough up the sharp cut using a Silicon Carbide conical grinding tip. Oh yeah, wear a dust mask, you don't want to be breathing ground glass!

Roughly grind the inside and outside of the edges using the Dremel. I also placed a strip of aluminum tape around the rim of the glass so that my grinding comes out as even as possible.

Continue to smooth out the edge using drum sanding attachments: I used 80, 120 and 150 grit. I would have used finer grits but that is all that I could find for the Dremel.

After a while, you'll have a fairly smooth edge that although usable, it is still kind of rough. Time to sand by hand using 200 grit sandpaper or finer.

You can keep going with a finer and finer grit, but if you want to finish the glass sometime this year, you'll call it a day after 200 grit.

You can also use a wire wheel on the lip, you'll get a shiny silver edge on glass that actually looks pretty cool.

johnqpublic6 years ago
Dry grinding of glass can pose long term health concerns. If done with any frequency it can lead to a disease called Silicosis. When preforming this instructable keep this in mind and try to do the grinding as a wet process.

Just wear a mask while you work? The glass dust will settle shortly after you finish and you can wipe it up with a sponge.

Frequent contact with dry glass dust will cause upper respiratory irritaion (think sore throat).  Coughing will typically clear that.  Silicosis occurs with long term exposure to silica-the main component in the production of glass.  You're concern for safety is appreciated.  Let's not forget saftey glasses and gloves too!

robbied4 years ago
@syntheticfibres. You should not use the dremel wet, what johnqpublic was trying to say is you should do it by hand. I've made a couple of drinking glasses this way, and some deeper shot glasses (from vodka mixer drink bottles) but having the glass dust floating around got too risky for me. you can use wet and dry sandpaper in the same grits as you would the dremel. Sure it takes a bit longer, but in my experience, by hand you can produce a perfect even finish, something i'm yet to master with the dremel. It also keeps the process wet, so no worry about glass dust.
ronmaggi4 years ago
I have these Popular Mechanics encyclopedias from 1955 that say to use a whetstone on the glass edges to smooth them out. I've never cut glass, but I thought I would throw that in. Using a rotary tool may be better... How much was the bottle scoring tool?
Iskaitinis5 years ago
Just made one, it was fun :)
Treshnell5 years ago
An alternative cutter is Ephrem's Bottle Cutter. It's also made out of metal, is easily adjustable, and comes with an accessory that allows you to easily cut on the tapered parts of the bottle (the cutting wheel needs to stay perpendicular to the glass for a good, clean cut).

The term "bottle cutter" is a bit of a misnomer, as mentioned, because you dont actually cut the glass, you're etching a line of very fine breaks.
Heat the score line with a heat source (Eph's cutter comes with a candle), then cool it quickly (rub ice on it, lower it into a bucket of cold water, etc). The contrast between the hot and cold breaks the bottle along the scored line.

Ephrem's bottle cutter comes with a silicone grinding power that you use to grind down the edge, and then you finish it with a bit of sand paper. It works perfectly well and results in safe glasses, but may not be as fancy as the dremel method outlined above.

BTW your instructable is way informative.
Yo, you use the wire brushes to polish up the edges? I've gotten mine ground down and rounded off but there seems to still be a bit of glass dust, etc. on the rims. I sent them through the dishwasher but they're still gritty...
tiger2tame5 years ago
Another way of heating the bottle after scoring is to take a peice of cotton string dippen in Alchol,  Ring it out a bit before putting it on the score.  Light it and then dip the bottel in water wile it is hot.  This is a trick a lot of glass cutters use.
My dremel's in the post and I've never used one before. How do I use it wet? Cheers.
great idea i have the bar in my town saving bottles for me i'm using them to make a bottle flower box i seena entire house made like this so i was looking for something to do with the extra bottles that i have. my husband does tile & mable work so i have a wet saw & dremel tool i would agree to use the dremel tool wet i also make opal rings using my dremel tool and i will dip the stone water grind for about 2 sec then dip in water again it keeps the dust down and keeps the stone from getting hot! Thanks for the great idea!
Mr. Rig It8 years ago
Excellent closeups and notations, good job.