Introduction: Impossible Metal Ring Through Coke Bottle

About: Hi, I'm Sam and I like to make things - check out some of my projects below. I worked for this site from 2014 - 2023 and have nothing but love for the Instructables community. Keep making great stuff!

This is what's called an "Impossible Object."

These types of objects are not literally impossible of course, as they are all created somehow.

These things are tangible illusions that can be held and inspected up close. They seem to defy logic and appear "impossible." They are great for gifts and are intriguing conversation pieces, and provide an interesting challenge to make.

The item I've made here is a solid metal 1/4" thick ring through two holes in the neck of a coke bottle. There are no visible seams on either the bottle or the ring.

Step 1: Inspiration

This was inspired by a great project shared by Jack Houweling on youtube where he puts a wooden ring through a Coke bottle: Impossible ring through glass bottle.

I wondered how hard it would be to create basically the same thing but with a metal ring instead of wood.

Metal is less deceiving than wood grain however . . . so while this isn't quite as cool as Jack's wood version, I thought it was a neat thing to make and have.

Step 2: What You Need

Here are the materials used for this project:

  • glass Coca Cola bottle
  • 2 1/2" zinc-plated metal ring, 1/4" thickness

Tools required:

  • glass cutting bits
  • diamond grinding burrs
  • carbide grinding burrs
  • rotary tool
  • drill press, clamps
  • sandpaper
  • metal polish

The basics of my welding setup:

Step 3: De-zinc the Ring

The first thing I did was put the zinc-plated ring in vinegar until the plating was completely dissolved.

This is important because while you can technically weld through the plating, it will release a toxic gas that is extremely hazardous.

So this is the easiest way to make common hardware items like this safe to weld.

I bought this ring at a local hardware store. They also had nickel-plated rings, which have a more shiny and almost yellowy-tint, but that plating cannot be dissolved in vinegar. The general rule of thumb is to never weld through platings. So what you can't safely dissolve, you should grind off down to bare metal.

Step 4: Drill Holes in Bottle

The bottle cap was very gently pried up from multiple points to remove it without deforming it. This way we can pop it back on later. Then I drank the Coke.

I set up a board on my drill press to which I clamped the Coke bottle.

The board was clamped to my drill press table, and a spray bottle was used to keep the drilling area wet.

The drill was set at a lower speed and two holes were made in the top of the neck of the bottle using a 5/16" glass drilling bit.

You have to go fairly slow and let the drill bit remove just a little at a time.

Step 5: Cut Ring

The metal ring was cut in two using a portable bandsaw.

Step 6: Embiggen Holes in Bottle Neck

I used a diamond burr in my rotary tool to grind the inside edges of the holes in the bottle, so the ring could pass freely and spin up and down without getting stuck.

This was done with frequent mists of water on the holes from the spray bottle.

Step 7: Weld the Ring

The ring halves were propped into position on my metal welding table, with one half going through the bottle holes.

The ring was then welded back together with several small spot-welds all around both joints.

Step 8: Grind the Ring

Using a carbide burr in my rotary tool, I carefully ground down the welds to match the ring shape as best I could.

I then ground all around the ring and intentionally went a little rough on it to give the whole thing a fairly worn and abused look. This worked to make the two welded/ground areas blend in and basically disappear.

Step 9: Polish the Ring

Some automotive metal polish was used with a couple of rags to quickly polish and buff the metal ring by hand.

Step 10: Wash Bottle Out and Replace the Cap

The bottle needed a good washing inside and out. I shoved some bits of cloth into the inside and swabbed them around with a thin metal rod to get the inside clean. These bits were then plucked back out with tweezers.

The cap was replaced and that was it!

Now it's up on a shelf with my other oddities and homemade "Impossible Objects" waiting for people to examine it and say "wait a second . . how did you . . ?"

Thanks for reading! : )