Gather your materials and choose a spot to work where the things you put together will not be disturbed before they are finished, such as a garage you can lock.
Remove the labels from a beer bottle and a 2-liter soda bottle and clean them. Then use the knife to cut the top off the empty 2-liter bottle.
Use a glue gun to hot glue the piece you cut off (it should be inverted) onto the top of the beer bottle. Then glue the soda bottle cap on top of this.
Drill a hole in the cap and through the middle of the wooden ruler. Screw the ruler to the cap. This will act as a support when you hang the bottle. Spray the bottle with cooking spray.
Place this assembly inside the 2-liter bottle, with the weight of the ruler resting on the edges of the soda bottle. Mix the liquid rubber compound according to the instructions and pour it around the beer bottle. Place a weight on top to hold the bottle down.
Let the compound cure for as long as the instructions of the package suggest. Then cut away the 2-liter bottle. Cut from the top about halfway down and all the way to the inner bottle. Pry open the mold and remove the bottle.
Mix 3 1/2 cups of sugar, 1/4 tsp. of cream of tartar, 1 cup of light corn syrup and 2 cups of water in a pot and slowly bring them to a boil, stirring often. When the mixture reaches a temperature of 300 F, remove the pot from the heat.
Spray cooking spray inside the mold and tape the cuts you made in the side closed. Pour some of the mixture into the mold. Immediately tilt the mold and begin turning it as you slowly pour the excess back into the pot. The goal is to produce a hardened coating on the inside of the mold.
Place the mold in the refrigerator for about an hour. Then remove the mold from the refrigerator and open the mold. You now have your breakable sugar bottle.