How to Cut Glass with String, Nail Polish Remover, and Fire (FIRE!)

I can’t tell you where I first saw this idea — no really, it’s all a blogosphere blur — but the technique is basically the same everywhere.  After all, it’s based on science, and for the most part, science is pretty much non-negotiable.

This has also been at the top of my to do list for 3 months… Did I mention that?  But as with most things at the top of my to do list, somehow it got put to the backburner… and then the holidays happened… and then I ran out of excuses.  So here we are today!

And now for your DIY/science nerd/crafty times pleasure…

Cutting Glass with a Piece of String, Nail Polish…


You will need:

  • a clean and empty bottle
  • string (I used yarn)
  • fire: a lighter, matches, whatever
  • acetone (or nail polish remover with acetone in it)
  • a bowl or sink full of cold water

(Here’s where I’m supposed to tell you to do this in a well-ventilated area with protective glasses and gloves.  Be smart, folks.  DIY/science nerd/crafty times projects are not a good reason to go to the hospital.)

First, take a bottle — any type of bottle will do, but I used a beer bottle in my case (a Brooklyn Lager bottle to be exact — holla!).  The bottle must be empty, so you need to make sure the contents have been disposed of, e.g., consumed.  You may have to take one for the team.  (Take one for the team responsibly.)

After the bottle is empty, cleaned, and dry, wrap a piece of string where you will like to make the cut (ideally, you want to do this so the curvature of the neck of the bottle is no longer part of the final product).  You can use any kind of string (as far as I know), but I used yarn in my example, AND I doubled the piece of string so it was a little thicker.

After you’ve wrapped the piece of string and tied it off, slide it off the bottle and soak it in acetone or nail polish remover that contains acetone.  After the string is saturated, slide it back onto the bottle.

The string marks the line where the glass will be cut, so unless you want an angular or jagged cut, make sure the string is level all the way around.

Then it’s fire time!  (Don’t worry, I’m not a pyro, it’s just that it’s rare that I get a chance to say a phrase like “It’s fire time!”– I felt I had to seize the opportunity.)

Remember that little ol’ safety warning I gave at the beginning of this thing? OK.  I’ve done my job.

Holding the bottle sideways with the bottom closest to you, use a lighter to light the string (and therefore the acetone).  I recommend lighting it in one place, and rotating the bottle by holding it from the bottom so it burns evenly all the way around. Once the flame has almost died down, quickly submerge it in cold water (I recommend a sink or bowl of water — as long as it can be fully submerged).  You will hear a loud crack as the two halves separate underwater.

After the two parts separate, you can recycle the top part (or reuse it as a funnel?) and keep the bottom half.  Ta da!   This is not one of those perfect, works-every-time kind of things; it may take you a few tries (it took me about three).

cut bottle yarn acetone

The most important things for this to be successful are the string being fully saturated and submerging the bottle right before the flame dies down.  If you wait until it has burned off all of the acetone, it will no longer be hot enough to break the glass (the hot part of the bottle + the cold water = the bottle separated in two halves).

The glass will probably still be a bit jagged, so these should definitely not be used as drinking glasses — unless you have a fancy dremel tool with a glass cutting bit (which I don’t have).

If you’re just going to use these as vases or votive holders (or candle holders, if you do the homemade-melt-your-own-candle-wax thing), then you can just try sandpaper or wet-and-dry emery paper (the latter of which I’ve never used before, but I hear tales of great success).

That’s it!  Gee, science is fun.

Anyone else out there a science nerd like me?  Anyone else out there tried this technique?  Feel free to leave comments below, or click on the title (permalink) above to redirect to a comment-friendly page.  Thanks!