Sugar glass is a common prop in movies, television and theatre because it breaks easily and looks realistic, but is much safer than real glass. Drinking from a wine glass made of sugar is not recommended, but it can be just the thing if you've always wanted to toss your glass into the fireplace, without breaking an expensive piece of stemware. Making sugar glass is actually quite simple. Making a mould in which to pour the sugar glass is the most challenging part of this activity.
Line the moulding container with clay. To make a two-part mould, you will need an open topped rectangular container large enough and deep enough to hold and completely contain the wine glass. Line the bottom of the container with plasticine or non-hardening modelling clay, deep enough so the glass can be laid horizontally into the container and embedded halfway into the clay.
Insert glass and make key marks. Carefully embed the glass into the clay so that only the top half is exposed and so that the bottom of the glass is pressed firmly against one side of the container. Use the end of a pencil to make four to six indentations about an inch deep in the clay around the edge of the glass. These will later serve as key marks to ensure the two-part mould is properly assembled.
Pour silicon. Spray the model wine glass with non-stick spray and completely cover the it in the silicon moulding medium. Allow 24 hours for the mould to set.
Make the second side. Once the silicon is hardened, the entire contents of the moulding container can be removed. The clay can also be removed, leaving only the model wine glass submerged halfway in hardened silicon. Return this to the modelling container, with the glass facing up, spray the exposed side of the model wine glass, and cover with silicon as in Step 3.
Remove model wine glass. When the second side of the mould has finished hardening, it should be easy to pry the two side apart to free the model wine glass. The key marks should make it easy to reassemble the mould, now hollow and ready to be filled with sugar glass.
Combine ingredients. In the saucepan, combine two parts water with one part corn syrup and 3 1/2 parts sugar. Add a quarter teaspoon of cream of tartar powder per cup of corn syrup used.
Boil. Slowly bring the mixture in your saucepan to a boil, allowing a full hour for it to reach the target temperature of about 126 degrees C as measured by the baking thermometer. Heating the ingredients too rapidly or too high will cause unwanted carmelization. In order to have clear, transparent wine glasses, monitoring the temperature during this step is essential.
Pour. You will want to coat the interior of the mould with non-stick spray (but not too much), pour in the hot sugar glass mixture, and let it sit for one hour in the mould until completely hardened. Keep the mould in place with rubber bands. Once removed from the mould, the sugar glass wine glasses should be kept cool in the refrigerator until needed.
Watch the video in the resources section for more tips on making a two-part mould.