There’s a few steps to go through when working with EVA foam. Let’s go through them together, so we don’t mess up the order. 🙂
- Decide your project
Let’s say we’re making an EVA foam shield for this tutorial. Since I am a Monster Hunter fan, let’s go with the shield from the Gold Rathian sword and shield weapon. - Make/buy a template
This shield lacks an available template/pattern/blueprint on the internet, so I made one myself in Photoshop. I will not elaborate on that here, as it is a process worthy of a tutorial on its own. 🙂
There are plenty of patterns for EVA foam crafts available on the internet. Kamui cosplay, Kinpatsu, CheeseCakePanda and PrimeProps are offering some great paid patterns. SKSprops, PunishedProps and R31 Studios have some great free patterns on their websites. So check them out first, before you make something. It can save you a lot of time. Print the template and assemble it. - Buy your foam
When you use a pre-made pattern, it usually comes with a guide on what kind of EVA foam you should use. Just follow those instructions to learn about foam and develop a feeling for the material. If you made it yourself: low density foam is great for organic shapes and high density foam works well for heavier props and armor. The thickness you need depends on the thickness of the project you’re working on. For the Golden Rathian shield, I picked High density foam of 10mm thick to make the base with. Also get yourself some contact glue in/and a squeeze bottle while you’re shopping. Maybe throw in some Flexbond/Mod Podge/Plastidip of some kind too. One of those is needed to make your prop look great. - Trace the template
The foam came in! Hurray! Time to start on the actual foam work. Take your assembled template and gently place it on the foam. If you got black or dark grey foam, I suggest using a white or silver marker for tracing the pattern. For lighter grey foam, a regular pen will do. Just make sure to not carve the pen into the foam. That will leave marks and we don’t want those.
Trace the pattern on the foam. I recommend going for first tracing all the patterns you need and putting those in a folder, so you can grab them again later to have a look at them. It helps when figuring out difficult parts. - Cut the outlines
Once everything is traced, grab a cutting mat or something that you don’t mind getting damaged. Put the foam on that surface. Grab a good, new box knife and it’s time to start cutting the foam. Try holding the knife as straight as possible to prevent slopes. Take your time during this step. Working slowly and making sure it is all clean, will greatly help with the look of your final product. And sharpening your knife will help too. Focus on the outsides of your project first. And possibly take a break after this step. Don’t overexert your wrist! - Cut details
Part two of cutting on a different day. The details, which in my case mean thorns, a cross-shape and more thorns. Refresh your knife and cut away. Keep those smaller details organised in a box, bag or any storage method you’d prefer. Just don’t lose them. That’s a real pain. - Glue it all together
Open up a window and don’t do this with pets around: contact glue is great for foam, but it is quite toxic. So ventilate well. Contact glue works best when applied to both surfaces that have to stick together. Then wait a few minutes and see if it is almost dry. When it is, stick them together, give it a good press all round. - Time to sand!
Your project (and my shield) should now look like they are coming together. But those weird edges of the blunt cut foam need some work. Dremels or multitools are favorites for that. Grab a proper protective mask and eyewear when using this tool. The foam particles are no joke on your lungs. I use the sanding bands for bigger work and the 925 aluminium oxide grinding stones for detailing. Don’t use a multitool/dremel for longer than 20 minutes without a proper break. It might be me, but I keep noticing shaking hands and hurting wrists after sanding this way for longer time periods. Prevent injury! Take your time. - Fix any gaps
Sanding your project probably exposed some gaps. Those can be filled with foam clay, kwikseal etc. Take a small amount of this stuff and press it into the crevice. Then apply pressure with your finger and move along the gap. This should seal the gap. - Sand again and detail the foam
The gap filling might have left material on the foam that you don’t want there. Sand it off by hand or with a multitool. But be careful not to damage the foam. When the excess has been removed, you can grab the multitool again for detailing or use a soldering iron to add texture. Once again: use proper protective gear when doing this and no longer than 20 minutes in one go. The Golden Rathian shield needed some ingrained texture and I use the multitool for that. By varying the pressure, I created organic looking wood grain-ish stripes. - Heatseal
We’re getting there with our foam crafts. Now it’s time to heat seal our projects. This closes the cells of the foam, making it a little shiny and less absorbent of everything that we’re going to apply next. For this part you need the heat gun and don’t go all out immediately! If you cook your foam, it is game over. So gently increase the temperature of your heat gun to a temperature that works for you. (I wish I could give you a temperature. But I work with an old heat gun that does not show what temperature it is on.) - Flexbond/Plastidip/clear glue
After letting the foam cool down, it was time to coat it in a flexible sealer. I work with flexbond as I don’t have proper space for using plastidip. To properly coat the foam, it is best to use 3-5 layers of sealer. Always let it dry properly in between! Flexbond can be watered down a bit to make it smoother when applying. Sanding can also help reducing brush strokes and giving the foam a smooth look. - Primer
Up next is priming your foam project. I prefer a spray paint primer in black, grey or white. Each colour brings out final colours in a different way. Some examples: white is great as a base for browns to make your prop look like wood. Black darkens the final colour, and I like to use that for bringing more depth to silvers. Grey is more neutral and is a great primer for almost everything. Remember that most paints aren’t fully opaque and thus choosing a proper primer will help your project look better. For my shield project, I chose grey primer. - Paint
This is one of my favourite steps. Paint brings your project alive and sells the idea of your prop being of the material you’re going for. I have fooled myself quite a few times with props in storage that I painted to look like heavy metals, but were foam and PVC pipe. They were lifted way easier than expected, resulted in almost tumbling over. - Varnish
Last step! Time to bring out the varnish to seal the paint job. Use high gloss for metals, satin gloss for plastics and matte for unpainted wood looks. So for the Golden Rathian shield, I used high gloss. Fern’s staff has matte varnish.
I believe this is the recipe for foam work in general. If I missed a step, made a mistake or if you have additions, let me know! This guide should be as comprehensive and complete as possible.
Keep on crafting!
Amirine