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Styrofoam is one of the most versatile materials on the face of the earth. Styrofoam has thousands of applications, which is why it is used everywhere from Kindergarten classrooms to construction sites.
While Styrofoam is great the mess it makes can be a pretty big detractor. It also has a much higher likelihood of falling apart when trying to shape it compared to wood or metal. This causes most people to throw Styrofoam away as soon as they get it. This is a shame because there are a lot of different craft projects that Styrofoam is great for.
However, if you just take a normal butter knife to a piece of Styrofoam you are going to make a huge mess and will probably end ruining whatever craft you were working on. In this article we have broken down the easiest ways to cut Styrofoam no matter what your needs. We have outlined 7 household tools you can use to cleanly cut Styrofoam into any pattern with no mess!
What is Styrofoam?
Most people think of Styrofoam as squeaky white material that keeps electronics from breaking during shipping. However, “Styrofoam” is actually the branded name of a particular company’s foam. Think of it like Kleenex compared to facial tissue.
Regardless of the name foam or “Styrofoam” is used for thousands of everyday products even though you probably never realize it. This includes plates, bowls, insulation, surfboards, and much more. The main “ingredient” of Styrofoam or any other foam boards is petroleum. The petroleum is synthesized into a substance called styrene through a process called polymerization. This can make styrofoam mildly harmful to breath in if you are cutting or breaking it down.
Score The Styrofoam Before Cutting It Manually (The Simplest Method)
If you are just looking to cut a piece of Styrofoam right down the middle, doing so manually is going to be the most straightforward option. Before cutting your styrofoam you should score your knife with hot wax to keep the blade from creating crumbs as you cut through through the styrene. You can also heat the blade by gently holding it over a flame. Cutting styrofoam manually is the most straight forward, cost effective option for basic cuts.
Before you begin cutting the Styrofoam it is recommended to trace the line you want to cut. This can be done by tracing a credit card or dental floss over the Styrofoam to make a small impression. Additionally gently running a knife over a candle is a great way to minimize the crumbling of the styrofoam. Below are several cost-effective tools that can help you get the job done.
How to Cut Styrofoam Methods
Hot Knife
A hot knife is our top choice for cutting Styrofoam. A heated knife is ideal for making small cuts and leaves minimal mess compared to a normal serrated knife. The key is to use a sawing motion when cutting instead of pushing straight down. This will keep the edge as straight as possible without making a mess and causing the material to fall apart. If using a regular knife holding it over a candle for 10-15 seconds will greatly improve the straightness of the knife. The heated blade also works perfectly for making cuts at different angles.
Dental Floss
This may seem like a silly option but it works great in a pinch. Dental floss is perfect for cutting through soft materials like Styrofoam. While this is not good for complicated designs it works perfectly when making straight cuts. It is best to trace a line with a credit card, ruler, or pencil before making the cut with dental floss. This ensures when you pull the floss down it will cut in a straight line. The best motion to use is to lay the Styrofoam on top of the dental floss. Then place one hand on top of the Styrofoam and pull the dental floss towards you with the other hand. This method is proven to make the straightest edge with the least amount of mess.
X-Acto Knife
Hot Wire Cutter
Eletric knife
An electric knife is a great option for cutting through multiple pieces of Styrofoam at once (or one extremely thick piece of Styrofoam). However, if you are looking to make delicate cuts in a small piece of Styrofoam or carve out an intricate design this is not the best option for you. Electric knife also tend to make a bit more mess than hot knives or dental floss. However, they cut straight and can tear through large pieces in seconds with virtually no effort required.
Foam Cutting Saw
If you find yourself having to cut through bricks of Styrofoam all the time the best option is probably a foam saw. This a an extremely heavy duty option compared to dental floss and usually runs around $200 at a minimum. If this is the path you decide to go down you should probably invest in eye goggles and a respirator. Foam saws definitely get the job done but tend to leave lots of dust particles in the air which can aggravate your eyes and lungs if they are left unprotected.
Cookie Cutters
This may seem even more ridiculous than using dental floss but cookie cutters are a great way to get premade designs out of Styrofoam with little to no mess whatsoever. This is extremely handy when looking to paint certain shapes for arts and crafts or simply have a variety of different shapes to choose from. Use a cookie cutter for Styrofoam the same way you would for cookie dough. Just press it down and you are good to go.
Frequently Asked Questions
Using a hot knife is the best way tool to cut styrofoam without making a mess. The heat from the knife seals the styrofoam and prevents the crumbling and crumbs that would be creating by sawing styrofoam with a traditional knife.
If you are going to cut styrofoam with a traditional knife or box cutter you should lightly wax the blade before cutting the styrofoam. This will ensure you make a smooth cut in the styrofoam and prevents the styrofoam from crumbling.
If you want to seal your styrofoam you will need to purchase a spray sealant to prevent damage or erosion from moisture. We recommend using polyurethane because it protects styrofoam from moisture and has a large selection of colors.
Many types of spray paint contain corrosive enamel that will cause styrofoam to fall apart. We recommend using oil or latex paint if you need to color your styrofoam creation.
Other Notes
If using a freehand knife cutting Styrofoam underwater will greatly reduce the mess. Styrofoam is actually waterproof so keeping it underwater for a minute or two will not damage the materials.
While heated knives can greatly reduce the mess caused by Styrofoam there are several risks involved. Some types of Styrofoam will release “off gassing chemicals” when heated. Essentially this means tiny particulates are released into the air when heated. Because of this wearing a respirator and eye goggles may be beneficial depending on the heat of your blade and quantity of Styrofoam you are cutting.
