This is the method I used to make my shoulder pauldrons and gauntlets for my Magic Knights Rayearth Fuu cosplay.
-Mod Podge (I use matte, not sure if gloss works just as well)
-Fabric Glue (Aleene’s Flexible Fabric glue works well)
-Craft Foam in the desired thickness for your project (I recommend 3mm for most)
-Rub ‘n Buff gold leafing wax in the desired color for your project
-400 and 600 grit sandpaper
-Floor wax (I used Pledge Floor Finish with Future Shine)
-Not so fancy paint brushes
-Not so fancy cup or disposable plastic cups
-Mixing stick (popsicle sticks or barbecue skewers work well)
I wish I could say I came up with this method on my own, but it is borrowed ideas and some experimentation! I have referenced Penwiper’s Craft Foam Armor Tutorial for some time, but ran into some issues: the wait in between layers was long, and the watery mixture dripped into pools on my curved pieces. I’m pretty impatient, as well. Fuu suggested that Mod Podge should be sandable – and by golly, it is! I tried using just Mod Podge, but I found that the pieces cracked under stress. I played around with some glue mixtures until I got something that worked and have been using this method ever since. Much of it is similar to other tutorials out there, but I thought I’d outline exactly what I did since I get asked about my armor so much.
Step 1: Pattern and cut your craft foam for your project. Glue the pieces together if needed. Foam is cheap enough, but I like to start with paper until I’m sure of the shape so I don’t waste too much. Heat form any curves you need. (Sorry, didn’t take a picture of the Fuu armor at this step, so Lina armor will have to do)
Step 2: Back the underside of your piece with fabric, just like the linked tutorial shows you. Lay down a layer of Mod Podge, lay down the fabric, smooth it down, and brush on more Mod Podge over it. You can paint it an appropriate color with acrylic paint. You can skip this step for small pieces or if your piece is already holding form well. This step helps hold curved shapes. (Sorry, no photos of this.)
Step 3: Mix your concoction in the cup. I use 2 parts Mod Podge to 1 part fabric glue. Mod Podge alone will crack when flexed, and Fabric Glue alone is sticky and doesn’t sand well. Mix them together and it’s perfect! Cover the cup with plastic wrap in between coats so it doesn’t dry out.
Step 4: Coat the outer side and edges with the mixture. Use at least 5-6 coats, waiting until each one dries clear. If you glued more than one piece together, be sure to fill in any obvious crevices. After your final coat, let the piece dry overnight. It’s OK if it looks gross with brush strokes or has uneven spots.
Step 5: Then, wet sand by hand! This will get rid of any brush strokes and create that smooth, mirror finish. A 400 grit sandpaper works well. From there, you can go to 600 to really get that smooth finish. This is delicate, so be careful not to oversand through all your glue layers. That’s why it’s important to build up several layers. To wet sand, I keep a cup of water, dip the sandpaper, and sand until the piece feels smooth and slick. Wipe it down with a paper towel, and then let the piece air dry sufficiently. The water may soak in, and you don’t want to paint over wet glue.
Step 6: Now comes the Rub ‘n Buff! I always just get down and messy and use my fingers! If you are seeing a texture, as the metallic makes really visible, go back and sand some more in those spots. Do at least 2 layers so that it is opaque. Then buff it with a cloth. Again, let it dry, but this stuff dries pretty much instantly.
Step 7: Again, like the original tutorial, take the floor wax, a cloth, and coat the armor piece. This seals in the color (otherwise it may rub off on your costume) and provides a flexible, glossy, finish! (It also smells nice!)
If your finished armor get smooshed or otherwise stretched out of shape, you may see some crackly marks form (kinda like stretch marks). Relax! They will go away once you put your armor back into shape and let it settle. Small dents can also form, but they will settle out over time as long as it’s not cut through the glue coating. This is nice to know if you cram your armor in a suitcase! You should still protect it, though.
Examples of finished/mostly finished pieces: