When looking at all the choices of EVA foams on the market today, how do you decide which is the best? There are several things to consider because not ALL EVA foams are created equally. I will do my best to shed some light on EVA foam and hope to not make the reading to dry.
First what is EVA? EVA is a plastic that is made by combining Ethylene and Vinyl Acetate. This combined product, EVA, is very soft and elastic. This combined product is rubber-like and very strong. A plasticizer (another tech word) is added to EVA to make EVA foam. This EVA Foam product can then be poured into molds to form shapes like: bun (which is a huge block that EVA sheets are sliced from), cones, dowels, flip-flops, dragon/fish scales, etc..
Is EVA foam toxic? EVA is considered a safe and a great alternative to PVC. There has been concerns that EVA foam contains a colorless, odorless chemical called Formamide. Formamide, not to be confused with formaldehyde, is used by some manufacturers to make the foam soft. If you are concerned if your EVA foam provider’s manufacturer uses Formamide (which is believed to be a carcinogen), please write them an ask them if their EVA foam is Formamide free. We are pleased to let you know that all the EVA foam that TNT Cosplay Supply sells is Formamide Free.
My EVA foam smells when I open the package, will this smell go away? Yes, when you first open EVA foam it has a very distinct odor. Your foam is packaged straight from the manufacturer. When you get your foam, open it up and set it outside or in your garage and after about 24-48 hours the smell will dissipate. I personally have rolls of EVA foam that have been in my home and they have no odor at all.
Now that we know what EVA foam is and how it made let’s talk about what it means when we talk about density and shore hardness.
What is EVA foam density? It is often believed that high-density foams are inherently firm which is not true. Density indicates quality and durability rather than softness or firmness of the foam. Density is the weight of the foam. So, if a product has a density of two pounds per cubic foot, it means when you weigh a 12”x12”x12” block of the material it would weigh two pounds. Often, EVA foam density is reflected in kilograms per cubic meter. This means if you weighed a cubic meter of a product and it weighed 80 kg. The density would be reflected as 80kg/m3. 
Again, let me state the density of the foam is NOT the firmness of the EVA Foam.
What is Shore Hardness? Shore hardness represent how firm or hard the foam is. Or, can also be described as the feel of the foam and how it gives to weight and pressure. One blogger I read referred to firmness as the “squishability” factor (my apologies for not giving credit as I could not find their blog again). So, what does this mean? The firmness is how soft or rigid the material is or how much pressure it takes to leave a permanent indentation in the foam. There are several different ways to measure the hardness of foam products. At TNT Cosplay Supply, we use the Durometer which is a gauge used to measure the firmness of the material that is being tested. The tool has a needle on a spring at one end and a gauge at the other end. The needle is placed against the material and pressure is applied  until the needle penetrates the material. The reading on the gauge is the Shore Hardness of the material.
At TNT Cosplay Supply, we have several different products with different Shore C readings. Our standard product, EVA-38, has a Shore C rating of 38. While our specialty foams such as EVA-50, EVA-60 and EVA-70 have much higher ratings. This means that these products are stronger it takes more pressure to indent the foam. Our EVA-70 is a very strong product that can easily survive the pressure put on it when being sewn or punctured to install grommets.
Which EVA foam surfaces is the best? There are many products out there such as rolled floor mats, puzzle piece floor mats, craft foam and foams designed for cosplay and prop making. Many of the floor mats have a non-slip texture purposely put into the product to prevent the person standing on the mats from doing just that, slipping. The textured foams tend to be of lower quality and can be harder to use because the texture often needs to be removed to create a smooth gluing surface or put to the inside of the product so that the outside of the item has a smooth surface. I will state however, there are cases where you want texture and, in those cases, the textured foams are perfect.
In the past the floor mats and craft foams were all that were available. But about five years ago, we started TNT Cosplay Supply as a solution to the EVA foam for cosplay desire. Now we have begun seeing EVA foams designed specifically with the Cosplayer / Prop Maker in mind. The foams have become smooth on both sides and of a higher quality in a variety of sizes and shapes. Now there are many choices on the market including big box store options. Even though most of the products available now are smooth on both sides, not all of them have a completely smooth surface, still requiring a ton of prep time to get the product ready to accept paint.
What does ALL this mean? When purchasing EVA foam, you need to compare the density (weight) shore (hardness) and surface (smooth or textured) of the products to determine which product is best for you and your needs.
 Furniture.com https://www.furniture.com/mattress/guide/glossary/high-density-foam “What is High Density Foam?”
 Chizel Blog Chizel.io/blogs “What is Shore Hardness? What Does it Signify?”
 Smooth-On www.smooth-on.com /page/durometer “The Shore Hardness Scale”