Content

• Steps
• Part 1 of 3: Installing the kiln
• Part 2 of 3: Preparing the bottles
• Part 3 of 3: The process of "flattening" a glass bottle
• Tips
• A warning

A flattened glass bottle can be an interesting figurine, tray, or cutting board. It is impossible to flatten a bottle with improvised means, but this is easy to learn and can be experimented with if you have a kiln for firing. Remember, if you have any glass incident, don't hesitate and call the emergency service immediately

Steps

Part 1 of 3: Installing the kiln

1. 1 Find a stove. To change the shape, the glass must be heated to 815º. To achieve this temperature, you need to find a local ceramics studio that rents stoves or purchase an electric stove yourself.
   • An electric oven often requires a new electrical circuit to be installed by an electrician. An oven connected to the wrong circuit will not be able to reach the required temperatures.
2. 2 Observe safety measures. When working with the oven, wear gloves and safety goggles, as well as a respirator mask when handling glass or cleaning dust in the oven, and always operate the oven in a ventilated area. Keep in mind that the kiln is hotter than a conventional kiln or fireplace. Before starting work, read the operating instructions for the kiln or ask an experienced ceramist or quartz glass artist for advice.
3. 3 Protect the bottom and shelves of the oven. If you skip this step, glass shards can damage the bottom and ceiling of the kiln during firing. There are three materials used as protection and a respirator mask must be worn when handling them. These materials can be reused even if they look uneven and damaged.
   • Glass cleaner (recommended) or oven cleaner can be purchased as a powder and mixed with liquid. Apply the product with a brush in four layers and wait until the composition is dry.Make the surface as flat as possible, as tiny irregularities will be printed on the glass.
   • Alternatively, cut the oven paper (cellulose paper) into a shelf shape. Place it in an oven and heat to 760 ° C to blacken it. It can then be used as a protective surface between glass and shelf.
4. 4 Place the shelf in the oven. It should always be raised above the bottom of the oven to allow air to circulate between them. Place the ceramic coasters on the bottom of the oven, then place the shelves on top of them. It's time to fire your bottles on the top shelf.

Part 2 of 3: Preparing the bottles

1. 1 Make a ceramic mold (optional). If you want to shape the bottle into a curved shell rather than a flat tray, place the bottle in clay. All molds must be protected with glass cleaner or oven cleaner as described in the section Installing the oven.
   • Use clay to heat the molds to 815ºC, otherwise they may melt during firing.
2. 2 We clean the bottle, remove the label. Three bottles of hot soapy water, or leave them in a bucket of hot water and household detergent for several hours. We wipe off the remnants of paper labels and stickers. If you want to save and reattach the paper label, peel it off with a hair dryer.
   • The printed labels will be able to withstand the firing process and become a design element if the bottle remains stationary during the firing process.
   • To avoid the possibility of fingerprints, wear gloves and wipe the surface with isopropyl alcohol.
3. 3 Use a devitrifying spray (optional). This product "interferes" with the devitrification or crystallization of the glass and causes cloudiness. Not all types of glass are prone to devitrification, and cleaning the glass can help. Use spray for blue and amber bottles.
4. 4 Add a wire hanger (optional). If you want to hang flattened bottles, prepare a wire in the shape of a hook and place it in the neck of the bottle. Bottles will fall next to the wire, so there is no need to secure it.

# * It is best to use hardened wire. The most common types of wire to work with are aluminum (can melt), copper and brass (can stain the bottle).

1. 1 Prevent the bottle from rolling. Place bottles or bottle molds on the oven shelves on their side. If they are likely to roll, prop them up with crushed glass (frits) or small pieces of paper. This will leave an imprint on the back of the bottle, however it is much better than a bottle slanted to one side, which can also damage the oven wall.
   • Be especially careful with labeled bottles. They must be motionless.

Part 3 of 3: The process of "flattening" a glass bottle

1. 1 Heat the oven to 590ºC. The oven temperature should be + 275ºC per hour until it reaches 590ºC. Start heating the bottle.
   • If you are using ceramic molds, you can use a slower heating rate to reduce the risk of mold cracking.
2. 2 Hold the temperature for ten minutes. "Placing" the glass at this temperature ensures that every part of the bottle is heated to the correct temperature. Pay particular attention to the steps below to determine how long to keep this temperature in the oven.
3. 3 Preheat the oven more slowly to 700ºC. This time, heat the oven to no more than 140ºC per hour, a little over an hour. At this stage, the glass begins to lose its shape, especially in the middle. You can maintain this temperature for 20 minutes if you want a flat, wide middle. Move on to the next step if you want the middle to retain most of its shape.
4. 4 Preheat the oven quickly to 790ºC. The oven temperature should rise + 165ºC per hour if using ceramic molds or faster if not using.Maintain this temperature until the bottle has the desired appearance.
   • This is a step that can vary significantly depending on your bottle, oven, and the look you want. Consider these numbers as a starting point for your first project.
   • Always wear eye protection when looking through the oven peephole. If your oven does not have a window or peephole, you will not be able to check the condition of the bottles.
5. 5 Ventilate the oven quickly until the temperature reaches 540ºC. Lift the oven lid - be careful at this point - quickly cool the oven until it reaches 480 to 590ºC. The less time the bottle is exposed to high temperatures, the less risk of devitrification or cloudy texture formation.
6. 6 Burn the glass. Glass may crack or become brittle when heated if not burned. It is a process in which glass molecules rearrange themselves into more stable structures before the glass cools. There are two ways to do this:
   • The simplest method, which is usually used for bottles, is to let the oven cool down gradually, no more than -80 ° C per hour. If the oven cools down faster, you will need to turn it on for short periods of time to prevent the rapid cooling process.
   • For more efficient annealing, leave the oven at 480ºC for an hour. Different types of glass have different optimal annealing temperatures, you can leave the oven at 540ºC and / or 425ºC for an hour, starting at the highest temperature.
7. 7 Let the oven cool to room temperature. The bottles should flatten. If you have used oven paper and the fibers remain on the bottle, wear a respirator mask to remove the glass.

Tips

• If you have removed the paper label and plan to reattach it, stick it to the back of the bottle for a neat visual effect and also to protect it from damage.
• Record your manufacturing process. A little experimentation and you will find the best one for your oven and bottles.

A warning

• If you open the oven too early, streaks may remain on the glass, this is caused by cool air entering the surface of the hot glass.