DIY Sugar Glass Bottles - Make a SMASH with your own fake Glass
We wont lie, our job can be pretty cool - swinging swords, creative fun and engaging choreography, using sets and props - there’s plenty to keep us on our toes and our creativity flowing.
As complex and safety conscious as our job requires us to be, we always maintain that with simple training and focus, anyone can build these skills. So with plenty of time on our hands looking for new skills, we thought we’d put together a bunch of resources you can follow to build your skills!
Now, one of the staples in many fight scenes, especially a bar room brawl is when someone is getting far to into the fight only for someone to appear behind them and knock them out with…a glass bottle.
I don’t want to spoil the magic for you, but unfortunately the bottles are not really made of glass. I know, I know, shocking, right?! Bottles for use in TV, Film and Stage nowadays are mostly made from a plastic resin designed to break easily but look and sound like glass. However, they originally were made from Sugar Glass.
Sugar Glass is exactly what it sounds like - it’s edible an edible sugar mix which shatters, something akin to glass. When sugar, water and a few other ingredients is heated to around 150 C/300 F it becomes very brittle, and if set into the shape of an empty bottle it makes a very convincing prop to smash over the head of a bar fight antagonist.
Below is a step by step guide on how to make a mould, making sugar glass and prop bottles. Our very own Michael J Warne followed these steps in his parents kitchen, so we’ll show you his result from this to show you how you can do this from the comfort of your own kitchen!
There is some cost involved to buy the mould-making silicone and release spray, but you will then have them to make breakaway bottles with as often as you like.
There are 2 similar guides we’re gonna follow:
We’re going to start by making the moulds. You'll need
1x 2 Litre bottle
1 x empty beer bottle, with all labels and glue removed
1x craft knife
2x trial units of Oomoo 25 silicon rubber mould making kit
Mould release Spray
Electrical, duct or gaffer tape
You start by carefully cutting the top off the 2 Litre bottle with the craft knife. The bottle needs to be empty (obviously) and dry, and have enough room either side of the bottle your casting a mould of (about an inch each side should be good). There also needs to be enough room to suspend the glass bottle inside the plastic one, with enough room on top to cover the top of it. Use your glass bottle to ensure you have the space inside the plastic bottle to make an effective mould.
You then need to empty the glass bottle your looking to cast, and remove all labels and glue from the bottle so it doesn’t interfere with the mould. Once empty, cleaned and dry, you’re going to want to create a balance so the bottle can be suspended as you pour the mould.
Now the above video recommends using a glue gun to glue to the top of the plastic water bottle to the glass bottle, and then the bottle cap inside of the little well created as pictured by my attempt here.
We would also recommend filling your glass bottle with water; this stops the bottle bobbing to the surface as you pours the casting silicone, which is exactly what happened in Michael’s very first attempt (which there are no pictures of - how fortunate for him.)
As you’ll then see from picture on the right, he drilled a screw through a plank of wood and balanced it on some wine bottles that were tall enough to suspend the glass bottle inside the plastic one, while leaving enough room at the top to get a full mould. However there is no hard and fast rule behind this, so however you rig your set up to get the right levels is up to you. Then, reading the instructions on your release agent, apply it to the glass bottle - if you don’t apply a release agent, the bottle can get stuck in the mould and ruin your hard work! Once you have it all set up, leave the set up ready to go, as we’re moving on to making the casting silicone.
Next, take your 2 tester sets of Oomoo 25. Oomoo 25 is a silicone rubber compound used to create moulds, so is ideal for this task. It can be bought in bigger bulks, but the 2 trial units gives us just the right amount to cast this particular mould. It has a very simple 1 to 1 ratio, meaning you just add both sets of part A to both sets of part B, stir and pour. Now, casting silicone has what is called a pot life and a cure time - the pot life is how long the the liquid takes to double in viscosity (thickness), and cure time means how long it will take to fully cure (set).
So, Oomoo 25 has a pot life of 15 minutes, and a cure time of 90 minutes. Now, as we’re just mixing the 2 together and pouring them into the plastic bottle, we have plenty of time to stir the 2 parts together before it starts to become unworkable.
In your mixing bowl you should add both bottles of part A, making sure to get as much from the inside walls of the bottle as you can. You then need to add both bottles of part B to the mixing bowl, again being sure to get as much from inside as possible. If you don’t the mixture can be too much of one part, meaning that it might not cure properly. Once added together in the bowl, take your paint stirrer and mix together. The 2 parts are different colours, but when fully mixed should be a uniform colour. You have 15 minutes before it thickens remember, so there is no need to rush.
Once you have fully mixed the 2 parts, its then a simple case of pouring the mixture into the plastic bottle, trying not to disturb the glass bottle as you do so. Once you’re done, it’s then just a matter of waiting the 90 minutes cure time. Michael sat his outside where it was slightly cooler, to make sure it was properly set - you can put in your fridge if you have enough room to keep it upright (again, just be careful if moving it to keep the bottle still, if it shifts it cant set off the mould slightly).
Don’t worry about your mixing bowl; set it aside and wait for the cure time to elapse. At that point you will then be able to pull the remains of the set silicone from the bowl. That’s not to say we’d recommend using your finest porcelain, but you don’t have to bin your mixing bowl after!
After the cure time has been reached, you can then take your craft knife and cut into the plastic bottle and the mould from the top to about halfway down. Be careful as you cut, and you may need to go back over the initial cut to reach the bottle inside. Once you’ve cut down far enough for the bottle to come out, grasp the neck of the bottle and wiggle its slowly as you pull, to make sure it comes out clean and without issue.
You should then have a clear mould ready to use!
Don’t throw away the plastic bottle you used though. You need to use it, and any bits of cardboard you have to bolster your mould meaning that you don’t have to worry about molten sugar leaking from it. Tape the cardboard around the plastic bottle and mould using electrical, gaffer or duct tape to keep it firmly held in place.
Next up is making the sugar glass. For this you’ll need -
3 cups water
2 cups granulated sugar
1 cup light corn syrup (or golden syrup, but more on this later)
1/4 teaspoon on cream of Tartar
Green or brown food colouring (optional)
Candy/Jam Thermometer - must reach 150 Celsius/300 Fahrenheit
This is as simple as adding all ingredients to your saucepan and heating them up.
Now, molten sugar is exactly that, molten! You need to get it up to 300 degrees Fahrenheit or 150 Celsius. If you get this on you it will burn and blister so extreme caution is advised, as are thick, heatproof gloves.
Start by adding your sugar and water to the pan.
You then add your light corn syrup - light corn syrup is what is known as an inverted sugar or “interfering agent”. The reason it is added is to stop the sugar recrystalising when it sets which would make it grainy and murky. You can buy Karo Light Corn Syrup from Amazon and eBay. If you cannot find any, Golden Syrup will also have the same effect (you can substitute 1;1 Golden Syrup for Corn Syrup. The only thing is this will colour the bottle amber, as you’ll see in later photos here.
This is the same for the cream of tartar, which is an acid but also acts as an “interfering agent”. Add this to the pan as well and your ready to turn up the heat. Cream of tartar is also slightly difficult to procure, but does come in bundled sachets - you only need a tiny amount for this.
The website below gives a bit more info, specifically on making lollipops, but it is pertinent to the making of sugar glass!
Bring the mixture to a boil very slowly. If it boils to quickly it will caramelise and be too thick to use. Using a sugar/jam thermometer you need to get it up to 150 degrees Celsius/300 Fahrenheit - it should take about an hour at a moderate heat.
This temperature is what is known in the baking industry as the “hard crack” point of sugar glass. Any less than this and it won't shatter, any more and it caramelises and becomes very sticky
Don’t stir the sugar mixture too much once it starts to boil, otherwise you agitate the sugars causing them to crystallise again…or something like that!
Once it reaches 150C/300F, if you want to add any food colouring now is the time to do so. A few drops should be plenty.
Before you pour out the sugar mixture you’ll need to spray the inside of your mould with your release agent to allow you to pull your sugar glass bottle out in one piece.
Then using your gloves, slowly pour the sugar mixture into the mould around the side of the mould if you can.
Once the mould is about half full, you will need to pick up the mould, and rotate it horizontally to coat the inside. Do this over the pot you made the sugar mixture in, as you’ll need to let any excess run out of the mould.
It might take you a few attempts at this, but once you’re sure you’ve got an even coating around the mould, leave it to set for about 2 hours.
Once that time is up, cut through the tape around the outside and remove the cardboard, then take the mould from the plastic bottle.
Slowly prise apart the 2 halves of the mould - if done correctly, the neck of the bottle should be easily reachable. Slowly and gently pull the bottle from the mould, and there you have it!
Ideally, your looking for a thickness of 1/8 of an inch across the whole bottle. This keeps it solid enough to keep its shape but fragile enough to shatter on impact with very little force.
The mould worked so well, after checking the remains of the bottle, we could see the brand of the bottle had been cast directly into the mould, and also the bottle itself!
Take care to look over the bottle very well. If any parts of the bottle are too thick you can still cause someone harm by using it, so be extra vigilant and take care of yourself or anyone you're planning on using this prop on.
Now sugar glass does not keep well in heat as it becomes very sticky, and is not a replacement for professionally made props. However this is a fun project you can make at home, and can help out in a pinch for a performance!
Here’s a video of some Michael made being used!
And there you have it! A re-usable mould you can use to create you own Sugar Glass Bottle props. Michael's been making a few bottles following slightly different recipes, and now that he has the moulds he's even been looking into breakable resins which are now more commonly used to breakable glass props - stay tuned for more of that and other props and effects you can make at home! If you do make a mould or prop bottle, let us know on social media - we'd love to see what you've done and share it!