EVA Foam for Beginners

We are a cosplay couple from Slovakia, Rys and Tor’Kaya, and we have been making costumes for over 5 years. Our favorite material is EVA foam, as we love crafting large armor and weapons. Rys wants to focus on creating large props in the future, whether from foam or other materials. His biggest dream is to build a motorcycle. Tor’Kaya would like to improve her pattern-making skills and learn how to work with casting techniques and electronics.

What is EVA foam and what is it used for?

- Ethylene Vinyl Acetate
- foam

Beyond making props and cosplay, EVA foam is primarily used for decorative elements, sports equipment, or various mats and cushioned surfaces. It is used in a wide range of densities and thicknesses.

At the same time, EVA foam is an excellent material for making the aforementioned cosplay and various props – from armor and weapons (such as swords or pistols) to boots and more.

It can also be used to reinforce so-called soft parts (dresses, trousers, shirts, jackets, and other "sewn clothing") or wigs.

What types and variants exist?

EVA foam comes in various forms, and all of them are great for making cosplay. These include classic sheets and rolls, foam clay, and pre-cut foam shaped into scales, circles, and other patterns, including edges and trims.

For beginners, standard rolled sheets are the most accessible and practical to use.

Foam density and thickness

The basic characteristics of EVA foam that are important for costume makers are foam density and thickness. Both have their own categories, and a potential costume maker needs to think ahead about what kind of foam they will need for their planned project.

Regarding density, EVA foam has several variants, each suiting different purposes, and costume makers choose based on the properties their props require. Foam density cannot be observed by eye, but it can be felt by touch; however, information from the seller is still important. A simple explanation of how density affects the final product: the denser the foam, the less flexible the result. The opposite is also true – the lower the density, the more flexible the product. If you want to make a prop that is rigid and won't bend, like a sword, use high-density foam.

Based on common characteristics and usage, they can be divided as follows:

1. EVA foam sheet (100 kg/m3) - Characterized by high density (HD). It is perfect for rigid parts of costumes, such as armor and weapons. 90% of costumes with rigid parts are made from high-density foam. Generally recommended for: helmets, breastplates, weapons, etc.

2. EVA foam sheet (50 kg/m3) - Characterized by low density (LD). It is suitable for costume parts where frequent bending is expected. Good examples include foam calf or thigh guards. Generally not recommended for: helmets, breastplates, weapons, etc.

3. LED foam - This type of foam usually has medium/moderate density. The main feature of this foam is its translucency, making it perfect for prop elements that need to let light through (for example, using LED lighting).

4. EVA foam sheet (150+ kg/m3) - This type of foam has the highest density (ultra-high density, UHD). It is ideal for static props like weapons – large swords, rifles, cannons, etc. It is not recommended for complicated or small details.

Furthermore, it is important to mention foam thickness. Unlike density, you can observe foam thickness with the naked eye (the differences are visible). Foams with different densities come in different thicknesses – from this perspective, it is important to correctly identify the foam sheet you need for your project. Because you can easily estimate foam thickness by eye, the properties associated with it are easier to explain – the thicker the foam, the larger it is. Foam thickness is measured in millimeters. Based on usage and availability, it can be divided as follows:

1. 3 mm - Used mostly for edges, decorations, patterns, and small details.

2. 5 mm - The most commonly used thickness overall. Elements most often made from it: armor, breastplates, helmets, larger decorative parts, etc. It is also suitable for large pieces that need to bend.

3. 10 mm - Mostly used for shields, swords, etc. Generally suitable for large pieces that do not bend.

Foam clay

Another standalone product that falls into the EVA foam category is foam clay. The material comes in a soft form – in hermetically sealed plastic containers. In appearance, foam clay is similar to modeling clay or plasticine. In the world of prop and costume makers, foam clay serves two main purposes: modeling elements and smoothing uneven seams.

By modeling elements, we mean imitating jewelry, fittings (buckles and clasps), or even more complicated structures like various remains (trophies, imitation bones, and skulls), etc. Activating foam clay is similar to working with the aforementioned modeling clay – it works on a water/air basis. To activate this material, you need to apply moisture using hot water, after which the foam clay can be shaped. Once the desired shape is achieved, the foam clay begins a passive air-drying process. Unlike modeling clay, it is not recommended to speed up the hardening process of foam clay using heat – the material is often ruined.

In a dry environment at room temperature (approx. 22 degrees Celsius), foam clay hardens over several days, so for an ideal result, it is recommended to work with this material without rushing. Once fully hardened, the material can be worked on with rotary tools and sandpaper.

Regarding painting this material, you can use the same paints used for standard foam. For a perfect finish, it is recommended to use a primer or sealer to seal the surface of the material; otherwise, there is a risk of cracking.

Contact cement

The basic and primary glue that costume and prop makers use when creating all kinds of foam joints is contact cement. It is a neoprene adhesive that works on the principle of contact between two surfaces. It functions differently from traditional paper (or other surface) glues – contact cement must be applied to both surfaces you want to join, then wait for a certain amount of time – usually 10-20 minutes, depending on how much glue is used. Once the glue is dry to the point where it is no longer sticky to the touch, press both surfaces together and hold. Only this correct procedure guarantees a truly strong bond, which is necessary for the proper use (and shaping) of the foam.

For easy use, a small applicator (tube) is also recommended. If you need to spread this glue over larger areas, a brush with a plastic tip is better than one with bristles.

Joints created by the correct application of this glue are very resistant to bending, temperature, and friction. If they are damaged, repairing them is also simple – a fact that foam as a material shares.

Other tools

Other essential tools you won't be able to do without when working with foam include:

• thin white marker
• craft knife
• self-healing cutting mat
• heat gun
• rotary tool

These basic tools are enough to process foam and subsequently make costumes. The white marker and craft knife are needed to trace patterns onto individual pieces, and the mat protects the table while cutting. It is very important to mention that the mat you cut foam on must not be wooden (like a kitchen cutting board). While you could use it, it would only last a few times before being destroyed. For these purposes, a special cutting mat is used (the high-quality ones boast self-healing properties). These mats have built-in scales and rulers that can help with cutting.

An essential part of every kit is, of course, a heat gun. It is a tool that, when plugged in, blows a strong stream of hot air. Today, you can buy one at any hardware or home improvement store. Their price reflects their features, but for basic foam processing for costume making, ones with at least 2 heat settings are sufficient (and in a way, necessary). One of the basic properties of EVA foam that determines its importance in the world of costumes is its flexibility and ability to hold a bent shape even after cooling.

Other properties of foam, including the ability to create a very smooth surface using heat, will be covered later in this article, but this is another reason why it is important to have a heat gun.

A rotary tool also plays a very important role, although it is not considered strictly necessary. Several different attachments can be mounted into a rotary tool to sand, smooth, or carve shapes into the foam.

EVA foam is an indispensable material for a wide range of creative and practical projects. Its versatility, availability in various variants, and ease of processing make it an ideal choice for cosplay, sports equipment, decorations, and many other applications. Thanks to EVA foam, you can easily bring your ideas to reality.

Continue.

authors: Rys and Tor’Kaya

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