This project comes with a clear “don’t try this at home” warning for two main reasons:
- It involves open flame and broken glass—exercise extreme caution and proceed entirely at your own risk.
- Despite repeated attempts, I couldn’t get a reliable result, so you may want to consider whether it’s worth your time.
I persisted through many tries because the idea sounded promising: turning beverage bottles into drinking tumblers by scoring a clean break around the bottle’s circumference. The instructions I followed were from a magazine article that made it seem straightforward, but my experience was much messier.
Even though the project didn’t work out for me, I’m sharing the process and what I learned in case it helps someone else troubleshoot or gives you ideas to try a safer approach. I filmed most of my attempts and included a video demonstration, but I’ll also summarize the steps and observations below. Note: extra safety gear—safety goggles, gloves, and a fire extinguisher—are strongly recommended. Glass plus fire is hazardous.
If you can’t watch the video, below is a written play-by-play that also covers the sanding step I accidentally left out of the footage.
Here are the supplies I gathered, based on the original instructions and a few extras I added for cleanup and safety:
- Lighter fluid and a small container to soak the string
- Glass bottles
- A lighter or matches
- Scissors
- String
- Cold water (I used a watering can)
- Sandpaper (for smoothing the edge)
- Paper towels for cleanup
I worked on a spare piece of patio slate to protect the driveway underneath. The basic idea is to concentrate heat along a single clean line around the bottle, then shock-cool that heated band with cold water so the glass breaks cleanly along the line, producing a straight-walled cup. The first step is to tie a string around the bottle where the neck begins to taper.
My initial test showed one loop of string didn’t concentrate enough heat on a Boylan’s bottle, so for the Izze bottles I used two wraps of string. After tying the string, remove it and thoroughly soak it in lighter fluid—try to avoid getting lighter fluid on your hands.
Once the string is saturated, place it back on the bottle and trim away any excess so the flame won’t travel past the intended break line. I rinsed my fingers in water after handling the soaked string to avoid igniting my hands when lighting.
The next step is lighting the string. The instructions suggested holding the bottle and rotating it so the flame spreads evenly; I tried both holding and leaving the bottle on the slate while ensuring the string was fully lit around the circumference.
It looks dramatic when the string burns—fire is definitely captivating—but the expected cracking sound didn’t occur for me after the recommended wait time. In most attempts I eventually poured cold water over the burning string and bottle, which usually produced a crack. If I waited until the flame had fully gone out before cooling, the bottle often didn’t crack at all.
The ideal outcome is a straight, even break like this:
In practice, many of my breaks were jagged and uneven, not something I would comfortably drink from.
I tried to correct the jagged edges by sanding. Sanding did smooth the rim somewhat, but getting a perfectly flat, safe top would have required a great deal of time and aggressive sanding. I did this work outdoors and recommend avoiding inhaling glass dust—wear a mask if you attempt sanding.
These were my three Izze attempts. I didn’t bother sanding the ones with extremely jagged breaks.
One issue with some bottles: printed or plastic labels can melt or burn during the process, so bottles with embedded or painted labels are safer than those with glued plastic labels.
Because I wondered whether bottle type mattered, I tried thicker IBC Root Beer bottles next. These were sturdier and had no plastic labels, but thicker glass was also harder to fracture cleanly. Some didn’t break at all, and the ones that did were still quite jagged.
Ultimately I didn’t keep any of the finished pieces. A few could have served as vases if the rough edges were hidden, but none felt safe as drinking glasses. I have several theories about why my results failed to match the original article—string thickness, bottle temperature, or glass composition could all be factors—but after a dozen attempts I’m calling this one unreliable for me.
If you’ve tried this technique successfully or experimented with safer alternatives, please share your tips and experiences. Better methods or small adjustments might make this project workable, and hearing from others could help someone else achieve a safer, cleaner result.