knife for cosplay

How to make a foam knife for cosplay

Everybody knows that conventions are not the places to be playing with life blades. I wrote this tutorial to show you how easy it is to create a prop that will work for your cosplay and you will be able to bring to your next convention. I created a blade using a special type of foam called plastazote. It is a bit stiffer and slightly different from normal foam as it has a rougher surface. However, it keeps its shape more easily than normal foam and is perfect for this project.

Making a foam knife for cosplay

Like any other project, you should start by making a pattern on paper. This way, you can modify everything you need before you start cutting and shaping your prop. It will also become your reference during the construction. My knife is the demon killing knife from Supernatural.

Once you have your pattern, you need to make it into smaller pieces. I used foam with two different thiknesses. As I only had a limited amount I couldn’t make my blade longer. If you can only find your foam in 5 mm you can cut two parts for your handle and glue them together. Use a box cutter to cut the pieces and make sure you hold it straight while you do so.

Of course, our knife is supposed to be 3-dimensional. In order to do so you need to use a rotatory tool in order to sand those corners until you are satisfied. Once you are happy with them, assemble your knife using contact glue. Don’t forget to put skewers in between the parts to make sure the knife has a secure core.

It is time now to add all the details, remember you can use a simple pen to carve those details into your foam. A pirographer is a good option for deeper details.

Once you are satisfied it is time to seal your foam and prime it before you start painting it. Remember to add lights an shadows to your weapon in order to give it a more prominent 3D shape.

As you see, making a foam knife for cosplay is rather easy. Now you have no excuses to go to a convention without a prop for your favourite character. What is your favourite prop to wear to a convention? Let me know in the comments.

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