Cutting glass bottles may seem like a complicated task that requires specialized tools, but a retired glazier revealed an ingenious and inexpensive trick: with a simple well-sharpened coin, it is possible to make precise and clean cuts.

This method is ideal for those looking to reuse bottles in craft projects, decoration or even to make glasses and lamps at home. The secret is to transform a common currency into an effective cutting tool, something that anyone can do at home with patience and a little skill. In this article, we explain step by step how to do it.

How to cut a glass bottle with a coin

Materials Needed:

To put this trick into practice, you’ll need:

• A thick metal coin (higher value coins are usually sturdier).
• A metal file or sharpening stone to sharpen the coin.
• Alcohol or hot water to weaken the glass at the cutting line.
• A lighter or candle to apply heat.
• A container of cold water to perform the thermal shock.
• Gloves and safety glasses to avoid cuts or accidents.

Procedure:

1. Preparing the Coin as a Cutting Tool

The first step is to sharpen one of the edges of the coin. To do this:

1. Place the coin on a stable surface.
2. Use a metal file or whetstone and start wearing down one of its edges until it’s sharp. It does not need to become a blade, but it does need to have a sharp edge marked enough to scratch the glass.
3. Test the coin on a glass surface to make sure it can make a visible groove.

2. Make the Mark on the Bottle

1. Place the bottle on a flat, firm surface.
2. With the sharp coin, press firmly and scrape the bottle into the area where you want to cut it. You should make several passes until the cut line is visible and deep.
3. It is important that the groove is continuous and even, without interruptions, to ensure a clean cut.

3. Apply Thermal Shock

1. Heat the cutting line with a lighter or candle. Run the flame around the groove for about 30 seconds.
2. Immediately submerge the bottle in cold water or pour ice water over the cut line.
3. The glass will split cleanly following the marked line. If it doesn’t cut off on the first try, repeat the heat and cold process until you succeed.

Tips & Recommendations

• Choose a sturdy metal coin. Copper or hard alloy coins work better than aluminum coins.
• Sharpen the coin patiently. The sharper it is, the more precise the cut will be.
• If the bottle does not break with the first thermal shock, do not force the glass. Repeat the heat and cold process until the cut completes on its own.
• Sand the edges with fine sandpaper or a glass stone. This will prevent dangerous edges from remaining.
• Use protection. Although the method is safe, glass can always chip, so it is recommended to wear gloves and safety glasses.