So…has anyone ever owned a bottle cutter? In surfing around, I see that there are a few different types out there (as well as a few sites that advocate making your own).
What types have you used, and what would you recommend? Any advice you can pass along as to the devices themselves, or about the actual process of glass cutting would be appreciated.
I don’t really have anything constuctive to say other than the one my mom had was cheap but worked well as long as you were very careful to keep the bottle level as you cut around it.
But on the subject of cutting things… I want to know is there anything you can use to neatly (and safely) cut CDs into not-too-intricate butterfly shapes? I’ve got an idea for a another AOL mobile, and the “cuts anything” scissors aren’t doing the job- it leaves things all jagged.
They all work pretty much the same way - the bottle is pressed against a steel-wheel glas cutter to make the score, and then you tap the bottle from the inside to run the score and break the glass.
Some tips:
[ul]
[li]Try to find out if the bottle cutter you are getting has a standard steel wheel or a carbon-steel wheel. It’s not important if you’re only going to do a couple of projects, but it you plan to do a lot with it, the carbon-steel wheel will last longer and give you better results over the long run.[/li][li]Keep a little lamp oil or kerosene handy - just a tiny bit, in a baby food jar or something - and use a cotton swab to dab a touch of it on the cutter wheel every so often. This lubrication is important, because a wheel that isn’t turning is scratching the glass, not scoring it.[/li][li]When you’re scoring the bottle (or using a glass cutter to score any glass) press down just enough to get a nice, clean “hissing” sound. Don’t push so hard that you get little flakes of glass popping up from the cut line. It’s actually harder to break glass well with a hard, deep score like that. Glass breaks best when the score is gentle, because the score should induce a crack in the glass, not be the first stage of hacking through the glass.[/li][li]Most bottle cutters make the score on the outside of the bottle and then require you to use some kind of tapping thingy to whack gently on the inside of the bottle on the score. Be patient and gentle. As you tap, you will see your score turn into a deep crack along the score line, and eventually the crack will go all the way through the glass and the bottle will be cut. After some practice you will learn how hard you need to tap to just get that crack to start. If you hit too hard, the score will run wild and not go where you wanted it, or worse, the bottle will shatter. Take your time![/li][/ul]
UD
(going on 20 years of teaching stained glass)
Wow…thanks Uvula Donor! That’s some great info. I was not sure how tapping on the glass was going to do the trick, but you explained it really well.
I was reading that you can also heat the score line over a candle and then submerge the bottle in hot water, but that sounds iffy to me.
And yes, without your advice I would have been trying to score the glass much too deeply. Thanks for shortening up the learning curve for me.
Any advice as to what to use to polish the cut edge so it isn’t so sharp?
Something like this ought to do the job nicely. Be sure to use a very fine-toothed blade to minimize chattering, which can result in chipping or cracking.
Fire polishing using a propane torch is a good way to go, IMO. It takes a bit of practice, and the trick is to both apply and remove the flame slowly to avoid rapid temperature changes which cause cracking.
Thanks, Q.E.D. ! I’ll try that 
I had occasion to cut some bottles a few summers ago, and just used a Dremel with a diamond-tipped blade. It chipped a bit, but if you polished it afterward, it would probably have been ok.
If you go this route, wear a dust mask. Personal experience.
Sorry to be so long to reply…
Q.E.D.'s suggestion to use a torch is a good one, but remember that it takes a delicate touch. You’ll probably be better off with MAPP gas instead of propane, for one thing, because it burns hotter. And try not to let the glass get red-hot. If you’re heating the glass that far, you are setting it up for stress cracks later on. Truly fired glass needs to be annealed after heating (brought up to temperature and then cooled slowly under controlled conditions) or the glass gets unstable. Carefully fire-polishing the edges will not require annealing, as long as you don’t overdo it. Practice on a couple of test pieces first.