If you’re starting to experiment a little bit more with cosplay, you may have come across the advice to use EVA foam. This is a great construction material that is both sturdy and lightweight, making it great for all kinds of cosplay costumes. It’s frequently used for armor pieces, as well as staffs, swords, shields, and any number of cosplay accessories.
I’ve compiled a list of questions that people have when creating props, armor, and accessories with EVA foam. If you’re completely new to using EVA foam, check out my beginner step-by-step guide here.
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How thick should the EVA foam be?
EVA foam comes in various thicknesses, usually 2mm to 10mm. The size you choose will be determined by the project you’re working on.
Generally, you should use the thinnest (2mm) EVA foam when creating details, dynamic shapes (such as horns), and simple armor pieces (such as arm bracers or leather-like armor). Medium thickness (4mm – 6mm) should be used for sturdier armor and basic props. Thicker EVA foam (8mm+) should be used for props that need to keep their shape and stand on their own.
You can also use multiple layers of EVA foam when necessary. For example, When creating a sword, I would usually choose to use 4mm EVA foam since I will have two layers sandwiched together to create the blade.
What type of EVA foam to use?
High density EVA foam works best for most cosplay projects. This kind is more likely to give you clean, smooth edges when you cut it. It will also keep its shape more easily when you heat-form the EVA foam.
If you’re looking for a slightly cheaper alternative, you can also use craft foam. It doesn’t hold it’s shape quite as well as high-density EVA foam, but it will work fine for most projects, especially if they’ll be held in place by other supporting structures (such as arm bracers against your arm).
If you want to get extra large sheets or more premium quality, there are also places like TNT Cosplay Supply that you can check out.
Is EVA foam toxic?
EVA foam gives off toxic fumes when it is heated (similar to the way paint thinner does). For this reason, stay in a well-ventilated area and use a face mask when you are heat-forming anything made with EVA foam. After the EVA foam cools down it will no longer give off toxic fumes and it’s safe to be around for long periods of time.
You also don’t want to inhale EVA dust particles when sanding since this can cause respiratory irritation. Stay in a well-ventilated area whenever you sand EVA foam and wear a face mask to prevent inhaling or ingesting the particles. I also recommend wearing goggles so that you don’t get any of the dust particles in your eyes.
Can EVA foam get wet?
EVA foam is water resistant but not 100% waterproof. This means that it’s okay for the foam to get a little bit wet if you’re out in the rain, but it can be damaged and distorted if it gets soaking wet. I don’t recommend bringing EVA foam creations into a pool unless they have been fully sealed with a waterproof primer or sealant.
Also of note, you do not want to pour boiling water on EVA foam since this will cause the foam to start melting.
Is EVA foam flammable?
EVA is not considered to be a highly flammable material, but it will start to melt at high enough temperatures (between 150º to 200º F). You should not put EVA foam in the oven and you should not keep it under sustained heat.
How to shape EVA foam?
To shape EVA foam you will want to use a standard heatgun on low heat. Wave the heatgun over the surface of the foam until you see a very slight change in the foam’s surface. Do not keep the heat focused on a single spot for too long, since this can start melting the EVA plastic.
After the foam is heated, you will notice that it is a lot more flexible than before. Turn the heatgun off and hold the EVA foam in the shape you want it to stay. Keep the foam in position until it cools completely. It will stay in the shape that it cools in.
Do you need a heatgun for EVA foam? (will a hair dryer work?)
A hairdryer will work to heat-form EVA foam if you do not have a heatgun available. However, hair dryers will take a lot longer to heat up the foam. You may need to spend 5 minutes or more blowing the foam to get it to a sufficiently high temperature (compared to 30 seconds with a heatgun).
If you are using a thick EVA foam (6mm or more), you may find that a hair dryer is not good enough for anything more than simple curved bends in the foam. However, it should work well for thinner sheets of foam.
How to harden EVA foam?
EVA foam will naturally have a flexible, spongy texture to it, even after it’s heated and cooled. If you want to make it feel like a hard piece of plastic, you will need to seal the foam with multiple layers of primer or sealant.
I will usually apply 3-5 layers of Mod Podge to get this effect. This is the cheapest method that I know of.
Other methods include using a clear wood varnish. You can spray 1 to 2 coats of this over the entire EVA foam piece to harden it. However, the varnish may crack if you attempt to bend the EVA prop.
For more permanent results, you can apply a layer of clear epoxy resin to the surface. Mix the resin with the hardener (they usually come as a kit together), and then brush it onto the surface of the EVA foam. Make sure to work quickly, since resin will begin its curing process 30-60 minutes after the two parts are mixed together. This is the method that’s easiest to mess up but will give you the best results if you can do it correctly.
What kind of paint to use with EVA foam?
You can use just about any kind of paint with EVA foam, but typically I recommend using acrylic paint. Even better if you can use a flexible acrylic paint. Flexible paints will bend with the EVA foam, making it less likely to crack and chip. I have used the brand PlaidFX with some of my EVA projects and like how they work.
Does EVA foam need primer?
In general, I recommend using a primer before painting on EVA foam, but it’s not completely required. The primer will add a non-porous layer between the foam and the paint which will help the paint colors be more vivid with fewer layers.
I usually use Flexbond as a primer for EVA foam. This is a flexible primer that won’t crack or warp if the foam is bent.
What glue is best to use with EVA foam?
I recommend using contact cement when gluing EVA foam pieces together. This gives a secure hold while allowing the seam to remain flexible. It’s also easy to wash off of your hands, and won’t melt if you need to heat-form after connecting the pieces.
Apply contact cement to both pieces that you’re attaching together. Then wait a few minutes for it to get tacky before attaching the two pieces. It will immediately give a decent hold and the seam will get stronger as the contact cement has time to fully dry.
Other options to use with EVA foam are super glue and hot glue. Super glue works well enough, but in my opinion, it’s more annoying to use since it’s difficult to wash it off your hands afterward. Hot glue should only be used if you do not intend to heat-form the foam since the glue will melt.
How to attach EVA foam to fabric?
To attach fabric to EVA foam, you generally want to add glue along the edges and wrap the fabric around. You want the fabric to be taut along the front of the foam piece so that you don’t end up with puckers and wrinkles in the fabric.
Commonly, people will use hot glue or contact cement when attaching fabric to EVA foam. I also recommend using heavy-duty double-sided tape if you are trying to attach fabric to large areas.
How do you seal cracks in EVA foam?
If you have cracks along the seams in your EVA foam creation, you can fill those in using a caulk adhesive (such as Kwik Seal). You can use your fingers to press the caulk into the cracks and then smooth it out. After the caulk has dried, you might need to sand the area as well.
The other option is to use foam clay to seal up any cracks. This is a type of rubbery clay that you can use. When it dries it will mimic the texture and behavior of EVA foam. However, it can sometimes be difficult to smooth out the foam clay, so you will probably need to sand it after the clay has dried out.
Can you sew EVA foam?
You can sew through EVA foam with a sewing machine or by hand sewing. I recommend only using a sewing machine with thinner varieties of EVA foam (2mm or 4mm) otherwise it may be too much for your machine to handle. But you can still pierce through thicker EVA foam pieces by hand-sewing. You can sew multiple EVA foam pieces together, or you can sew EVA foam to fabric. You can also sew the foam for stylized reasons. For example, to make the foam look more like leather.