I've always wondered about sugar glass, and was surprised at how easy it was to make. You can buy everything you need for homemade sugar glass at the grocery store and make it in your kitchen. In the end this recipe produces a sheet of sugar glass that is perfect for your indy movie.
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Step 1: Shopping List
1. A big bottle of white corn syrup.
(I bought the one quart size.)
2. A can if non-stick cooking spray.
3. A big bag of white sugar.
(You can always use more sugar, buy a pound!)
4. A candy thermometer.
(Chances are you can borrow one of these.)
5. Cream of Tartar.
(Turns out this is actually a powder, you can find it in the spice section.)
6. A big pot.
(I read somewhere that the pot would be ruined after you make this, but mine was fine with a
7. Measuring cup.
(Again you should be able borrow this if you don't already have one.)
8. A Mold.
(For a sheet of sugar glass all you'll need is big cookie sheet, but you can make more
Step 2: The Mix
It doesn't get any easier then this. The proportions I used for a 17"x11" sheet of glass is as follows.
2 cups water
1 cup corn syrup
3 1/2 cups sugar
1/4 tsp. cream of tartar
Now mix these ingredients into your pot and SLOWLY bring them to a boil. If you heat it too rapidly the mix sugar will caramelize (become yellow and burnt). Depending on the altitude your sugar glass mix should start to boil around 160-200*F. Your mix will start cloudy and white, but as it starts to boil it becomes clear.
If you're heating it at the right pace, it should take at least an hour to reach our target temperature, which is 300*F. My first batch started turning slightly yellow at about 290* and resulted in yellow glass. The second batch I removed at 260*, and while being more clear, it was very soft. My remedy, put it in the refrigerator until you need to break it.
Step 3: The Mold and the Pour
The simplest mold to use is just a big cookie sheet. I used a standard 17"x11" size. First thing you want to do is spray the crap out of your sheet with cooking spray. This will allow the glass to come out of the mold when dry. Now once your sugar glass mix comes off the stove it will start to dry fast. So don't wait long to pour. Go slow making sure to spread the mix evenly across the mold. I even picked up the mold and rocked it back and forth to get the mix level and in all the corners.
There might be some small bubbles on the surface. Most of these should go away, but feel free to (carefully) pop them with something pointy. Now just wait 1 hour!
Step 4: The Removal
This can be a difficult process. What finally worked for me was to take a knife and heat it up under hot water, then carefully cut along the very edge where the glass meets the edge of the pan. After that I was able to carefully pry it up. Then flip it over and slowly lift the pan away from the sugar glass that is resting on you hand.
Step 5: The Execution
Sugar glass does not last long...at all. As I said before, keep it in the fridge until you need it. After only 10-15 minutes at room temperature the glass will start to sweat and get sticky. The longer you leave it out the more it will just bend instead of break.
There are tons of creative ways to use this stuff. You could try and make a big window out of smaller sheets, break a fire extinguisher case, or just break it and stick it to your actors face to make them look like they just went threw a window. Just keep in mind that you can still cut yourself with this stuff.