Reddit mentions of g2 Bottle Cutter

100% agree. I found that a glass cutter like this:

http://www.amazon.com/Generation-Green-g2-Bottle-Cutter/dp/B004ZRV3AU

works well. Only difference is after you score (slightly cut) the glass, you can stick it in super hot water and then into ice water and it will make a clean break. Messing around with the dinky hammer is a waste of your time. Afterwards, wetsand it. You can do this by getting a container, putting sandpaper in it, and then putting water on top. Then, twist the glass around in the water against the sandpaper. This make it so the glass granules don't go in your lungs. Instead, it stays in the water, and you can empty that afterwards.
I helped a friend make a bunch of wine bottle glasses for his wife for Christmas, and we ruined 9 bottles before we found the right technique.

I have one of these, it works great. I just score the glass, and pour boiling water over it for a couple seconds, followed by a dip under cold water. Dozens of clean cuts and no issues yet.

I cut off the bottom off the bottle using this bottle cutter , silicone caulk'd the pineapple and the rocks to the bottom, and then used silicone caulk to reattach the top and bottom.

This method gives you some pretty jagged edges and is way less than 80% effective. Glass cutter mounted to a board seems to work best from what I've worked with. This and this also work pretty well but cost more than a $3 glass cutter mounted to some scrap wood.

Get this tool. You set it to where you want to cut, then score it just enough to give it a good line.

Then alternate putting the bottle under hot and cold water, keep alternating, and the top should just pop off. I'll try finding one of the bottles I did this way, and it turned out perfect.

EDIT: Follow what this guy does. It's the same method I used to do mine. Here's a 3 pics of how my bottles turned out.

http://i.imgur.com/lko2kHV.jpg

http://i.imgur.com/gXa44wa.jpg

http://i.imgur.com/dyFcWXL.jpg

I do something similar, here is my process:

1. Score glass with http://www.amazon.com/Generation-Green-g2-Bottle-Cutter/dp/B004ZRV3AU/ref=sr_1_1?ie=UTF8&qid=1344673890&sr=8-1&keywords=wine+bottle+cutter
   
   
2. Heat score mark with tea candle.
   
3. Use very cold tap water to cool down, wipe excess water off with paper towel (the towel will have tiny shards of glass so don't use a towel you will use again).
   
4. Repeat until the glass breaks all the way. If you use very cold water it will break clean about 90% of the time, sometimes glass just does what it wants.
   
5. I take the glass and attach it to a drill. I use a thick strip of cardboard across a buffing back-plate. A hole through the center of the cardboard allows you to use the screw that normally attaches the buffing pad.
   
6. I wrap the cardboard around the sides of the glass and use a lot of rubber bands to keep it in place. Sounds flimsy, but I've never had the cardboard break on me, just keep it dry.
   
7. Buy some diamond sanding pads http://www.amazon.com/3M-6002J-Diamond-Hand-Pads/dp/B004R4KUMI/ref=pd_sim_hi_1 put it in a waterproof plastic container with a low edge.
   
8. Wet down the sanding pad with some water, glove up a hand with a disposable glove, hold the glass in place and grind until you have a perfectly flat surface. Now angle to create a smooth outer edge. Prop the pad up on something in the container and use a corner to grind the inner edge.
   
9. Polish with Cerium Oxide http://www.amazon.com/CRL-Cerium-Oxide-One-Pound/dp/B000KZWDTG/ref=sr_1_1?ie=UTF8&qid=1344674583&sr=8-1&keywords=cerium+oxide on a wet sponge.
   
   I started looking at videos like the ones linked on this page and ended up at this process. The tea candle and water method works pretty great, the wet grinding is better as there is no glass dust, the cerium oxide removes all the frosting and makes the glass look very clear.
   
   I hope this helps you get started if you have the desire.
   
   http://imgur.com/TcRgu,bkwEd
   http://imgur.com/TcRgu,bkwEd#1
   http://imgur.com/B3XDy
   
   Sorry I don't have better examples, this is all I have lying around. The good ones I given to friends and family.

Not OP, but the easiest way to cut glass bottles like this is with a glass bottle cutter like this or this.

I've been cutting bottles like this to make wine bottle candles for my centerpieces and my favors!

Here is a cheaper option I've used and after some trial and error I get a flat cut on 80%+ as your friend does. From there its just some minor sanding with emory paper.

Use this instead:

http://www.amazon.com/Generation-Green-g2-Bottle-Cutter/dp/B004ZRV3AU/

Results:

http://imgur.com/yOVc6r9

The Rogue ones are old, forgive me.

It’s for cutting the tops of wine bottles.
g2 Bottle Cutter https://www.amazon.com/dp/B004ZRV3AU/ref=cm_sw_r_cp_api_nI03BbCQ5JZCB

I linked to it at the top of the guide :) This is the one I used (from the photos): http://www.amazon.com/Diamond-Tech-Crafts-Bottle-Cutter/dp/B004ZRV3AU/

They also have it at Michael's for around $20, but if you wait for one of their 50% off coupon days (which they do like every month) you can get it for 10 bucks, which is cheaper than Amazon.

You can always buy a bottle cutter and drink a lot of wine for the empties :)

http://www.amazon.com/Generation-Green-g2-Bottle-Cutter/dp/B004ZRV3AU

I used one of these: http://www.amazon.com/Diamond-Tech-Crafts-Bottle-Cutter/dp/B004ZRV3AU

[If you live near a Michael's Craft Store, they always have a 40% off (sometimes 50%) coupon that you can print from their website. I think it was $25 in store, which still beats Amazon's price after using the coupon.]

After following the cutting directions I alternated dipping the top half of the bottle in a pot of boiling water then a pot of cold water for 5-7 seconds in each, until the top popped off. Wet sanded it (to keep glass dust from going everywhere) flat with 80 grit paper and then used 220 grit to smooth down the sharp edges.

Word of warning - make sure you carefully clean out the pots when you are done! There tends to be very fine shavings of glass at the bottom and if you use the pot for anything else it might end up mixed in!

A bottle cutter.

I have done this with Stone bombers before except I used a cutting tool. It worked really well once you get the hang of it though I did lose a couple bottles in the learning curve. The bomber fits a regular sized beer perfectly. I would note that sandpapering to a nice curve takes a while so don't be surprised with that aspect. Also they seem dishwasher safe though I worry the printing may come off eventually so after awhile I switched to hand washing.

Cutting it cleanly is not easy!

I used this bottle cutter that scours the glass and then I dip it in boiling water and ice water to get it to break apart. Every cut is different, but having really cold water and really hot water helps. Then sand the edges down to make them a little bit smoother.

I bought this onefrom Amazon, I am 2 for 6 in making glasses out of them but still trying, plus I like emptying the bottles!!

First successful attempt:
http://imgur.com/mlow7

Actually, I used this.

Failure rate is high, so I suggest collection a bunch of bottles and cutting them all at once, then polishing the survivors. Let me know if you'd like to hear more about it.

For $20 you can get a special little cutter kit thingy that helps you make even breaks.

Buy this for 20.00. Don't waste your time with the string and all that other jazz.

http://www.amazon.com/Generation-Green-g2-Bottle-Cutter/dp/B004ZRV3AU

It works great on basically anything bottle sized/shaped.

You will have far less headaches, and you don't need a torch, the flame from a tea candle is more than adequate.

Digitec was super overpriced when I went to buy my mouse. And electronics isn't the only thing that I use Amazon for... I want to buy a wine bottle cutter, and I have no idea where to buy it. At home I would just order it online. I mean maybe a craft store, but I don't think craft stores have this in stock.

I spent a few months cutting old beer, wine and other bottles. I must've made around 60-70. Here's some stuff that helped me...

For the sanding - You can use increasingly finer sand paper. Just wet the tip of the cut glass and put the sand paper on a flat work area. Apply a little pressure and go in a sort of figure 8. (Having a cleaner cut is obviously easier in this process.) I also used a Dremel with a stone polishing tip for the not so clean breaks, haha.

For scoring - This is the glass scorer I used that made things easier...

Diamond Tech Crafts G2 Bottle Cutter https://www.amazon.com/dp/B004ZRV3AU/ref=cm_sw_r_cp_api_ANIRzbVW9KYHQ

Apply a little bit of pressure, but not too much when scoring the bottle.

For the cutting/breaking - This is the tricky part. I've tried a few methods a, but the candle/ice water trick seemed to work the most often.

Take the bottle and roll it over a small, lit candle for about 20-30 seconds. About 1-2 inches away. Then, immediately, dunk the mouth of the bottle into a pitcher of ice water to just cover the score. Might take a few tries, but this tends to work the best. For me at least.

Best bottles to use - The 16.9 ounce beer bottles are the easiest to get a clean break. They have thick glass which holds the best when breaking. Wine bottles are usually pretty good. Just depends on quality glass really.

that one seems a bit big, possibly smaller ones are cheaper?

hole saw set - says diamond tipped
http://www.amazon.com/SE-Diamond-Hole-Saw-Set/dp/B000SJ2TL6/ref=sr_1_6?s=hi&ie=UTF8&qid=1334198775&sr=1-6

hole saw - 1 bit 3/4 inch
http://www.amazon.com/DEWALT-DW5582-4-Inch-Diamond-Drill/dp/B000VRBENO/ref=sr_1_1?s=hi&ie=UTF8&qid=1334198775&sr=1-1

dremel kit - must have a dremel for sufficiENT speeds
http://www.amazon.com/Pro-Quality-20-Piece-Diamond-Point-Rotary-Tool/dp/B000MOI9G6/ref=sr_1_4?s=hi&ie=UTF8&qid=1334198775&sr=1-4


ALWAYS MEASURE TWICE and CUT ONCE
I used a half inch spade bit and it kinda cracked my first one

http://i.imgur.com/T9w9t.jpg

Has slide to bottom and then removable bowl
stuff at neck is hot glue for a air tight seal, glass was to thick for gromit that came with the slide


bottle cutter - for other fun things
http://www.amazon.com/Generation-Green-g2-Bottle-Cutter/dp/B004ZRV3AU/ref=pd_bxgy_hi_text_b

I bought a product to help score the bottle, something like this, but I've seen some tutorials that do it with just string and acetone.

I bought this one off amazon for about 18 bucks for my girlfriend for her birthday so she could cut wine bottles. It took me about 2 tries to get nice clean awesome cuts with it. It is worth it if you want to get into making candles out of bottles!

I've had success using a scoring tool specifically for bottles like this:

GreenPowerScience demonstrates a pretty effective technique of scoring, then alternating boiling water and cold water around the score mark until it breaks. I've found that if you use rubber gaskets or hair ties around bottle on either side of the score mark, it keeps the temperature changes localized to where you want it to break. With the hair ties I get a perfect clean break every time. Before I tried that there would often be chips and erratic cracks

Just this guy.

One like this for $18 http://www.amazon.com/Generation-Green-g2-Bottle-Cutter/dp/B004ZRV3AU#