You can build your gauntlets from lots of different materials, including old coffee cans, cardboard tubes, felt, or even cardstock. We'll show you here one method using craft foam sheets.
Check out EPBOT for an excellent tutorial on using craft foam for realistic cosplay bracers!
Create the cuff body by cutting one sheet of foam into an appropriate width and length -- here about 7" x 18". The short side will be the height of the cylinder, the long side will be the circumference.
Use tacky craft glue to form an adhesive strip along the edge of one length of the foam.
Roll the foam into a cylinder and press the edges together.
Place a weight on the seam to hold it in place while it dries. Note -- this can take a half hour or so to hold and up to 24 hours to fully cure! You may choose to use small dots of hot glue to tack it in place more quickly.
An alternate or additional way to secure the foam is with plastic pop rivets.
To use, poke a small hole with a scribe, awl, or pencil through the overlapping foam edges and then push the rivet through from the outside in.
Place the retaining ring over the back side to secure.
We'll hang the battery pack from it's belt clip on the inside of the gauntlet.
Cut two small slits in the foam near the middle of the gauntlet. This is where the Circuit Playground Express and star will be.
Hook the belt clip through the slits.
Route the battery cable through one of the slits to allow it to plug into the Circuit Playground Express later.
To attach the Circuit Playground Express case to the cuff, we'll use a small foam strip through the case back.
Feed the strip through the strap cutouts in the case back.
Place the Circuit Playground Express into the case.
Make sure to align the slide switch positions of the case top and the CPX, then place the top of the case on, clicking it into place.
Plug in the battery cable. (You'll use the battery case's on/off switch).
Use tacky craft glue to adhere the strip to the gauntlet cuff.
I used a few rulers and spring clamps to hold the strap in place while it dried. You could use some books for weights, or small dots of hot glue as well.
Now, we'll decorate the CPX case with a yellow star -- which will also act as a light diffuser.
Use scissors or a hobby knife to cut out a star from some yellow foam.
Clue the star to the case top using a small dot of hot glue.
To match the style of the gauntlet, we'll add a strip of black foam around the bottom of the cuff. You can use a combination of glue and pop rivets to secure it.
The craft foam on its own is a bit floppy, and will be very loose on your wrists. In order to address both issues, we'll use some foam core board to create a top and bottom of the cylinder with holes cut in their centers for your arm to fit through.
Trace the base perimeter onto the foam core board with a pencil.
Use a hobby knife to cut it out.
Trim the edges so it fits well inside the gauntlet cuff.
Cut out an oval from the center that will allow your arm to fit inside.
Repeat this for the top board by tracing the first one.
Glue both in place with a thin bead of hot glue.
It's time to put your Garnet's Gauntlet to use! Turn on the battery pack's on/off switch. Then pull on your gauntlet and deliver a strong air-punch!
You can even dress it up with a red glove or even add additional foam cutouts if you like.