This was my first time building a full foam costume like this (and took just over 100 hours to complete) and I must say, I am quite proud of myself. As such, I want to keep how I did it a complete secret!

Just kidding (why would I be posting if I was?)! Hopefully some of the techniques I used will help you on your future foam build. I am free to answer any questions and I will also include additional resources that I used throughout this build as well at the end so make sure to read through those!

Before we officially begin, I want to go ahead and give credit to this art of a Samurai Boba Fett by cgfelker that I used for inspiration.

Supplies

Floor Mat Foam

Craft Foam

Googly Eyes

Velcro

Contact Cement

Hot Glue Sticks

Super Glue

Elastic Band

Acrylic Paint

Mod Podge

Buckle

Tools

Rotary Tool

Heat Gun

Butane Torch

Utility Knife/Box Cutter

Hot Glue Gun

Old Soldering Iron

Step 1: The Helmet (Kabuto: Japanese Traditional Helmet)

With some modifications, I used this Boba Fett template for the helmet. I didn't worry too much about seams since I would be covering these with additional pieces of foam later.I used drywall sanding screens for the visor portion and was sandwiched between the floormat foam and the craft foam.

Step 2: The Brim (Mabizashi)

For the bill, I took a piece of wire and bent it from the middle seam of the helmet to just above the edge of the visor on either side. This gave me half the curve I needed for the bill. I traced out the wire on a piece of folded paper, completed the overall shape of half the visor, cut out this pattern, opened the paper and suddenly i had my full pattern. I used this pattern on some floormat foam and added craft foam details in addition to rounding the edges with my rotary tool.

Step 3: The Crest (Maedate: Helmet Crest)

The crest was made from pieces of floormat foam contact cemented together. I later add a coat hanger wire to the back of this with some craft foam to hide it to give it some added support because I didn't like how floppy it was. I did all the detail-work with the crest using my rotary tool's ball grinding bit. Had I known about foam clay it would've made the entire process much easier, quicker, and cleaner. Since I carved it out however, it was rather rough in the end so I used some Kwik Seal to help smooth the edges. I also ended up doing a mixture of Kwik Seal and acrylic paint to help smooth it out as well (this seeeemed to help but I could be completely wrong). The circular details were achieved by taking the end of the rotary tool and pressing it into the foam.

I change the way I attach the crest throughout the build. Originally I wanted it to be detachable so I tried using snaps and velcro but due to the strength of the attachment point, I ended up just using contact cement and permanently attaching the crest to the helmet.

Step 4: The Shroud (Shikoro: Nape Guard)

I seem to have lost some of the pictures I took as I made these plates but no matter...

I have a Darth Vader helmet and his shroud is actually what I used to get the right angle and curve for this helmet. I used some masking tape along the curve, refined the shape, and cut it out on foam. I then made additional copies of this template with each added section larger than the previous. These were all overlapped and glued to each other. Additional pieces of foam were used for the fukigaeshi. I poked holes vertically throughout the piece so I could add yarn to make it look like all the pieces were laced together after it was painted.

Step 5: Painting

Before I painted, I used my heat gun over the entire piece to help seal it. I also super glued strips of foam over the seams as well as googly eyes for rivets. The googly eyes were scratched up with a Scotch-Brite to help give the paint something to grab onto as it won't adhere to the typical glossy plastic finish.

All pieces got a thin layer of Mod Podge added on to prime and seal the foam. Then the base coats of red and green acrylic were painted on. After everything has been painted, the yarn was threaded through the holes I had poked through earlier.

Step 6: Weathering

Here comes the real fun part...weathering.

I watered down some black acrylic paint and painted over the entire piece making sure to pay special attention to the recessed areas. I then took a rag and wiped most of it away to reveal the high points. I repeated this process until I got the effect I was looking for.

Finally it was painted once again with a thin layer of Mod Podge to help protect the paint and give it a satin sheen.

Step 7: The Bracers and Greaves (Oda Gote: Forearm Guard | Suneate: Shin Guard)

The bracers were patterned off of the design I provided at the beginning. I had measured the circumference of my wrist as well as the larger point of my forearm. This made a trapezoidal pattern when drawn out. Additional modifications were made to accommodate the shape I wanted. I used a heat gun to really help curve the piece and glued smaller pieces of foam at the ends of the main piece to help hold its shape. I used my rotary tool to round off corners as well as make the inner groove. I also used it to make additional markings for battle damage. The greaves were actually made from a failed attempt at the bracers. I carved out grooves to help match the illustration once again and added elastic bands to the back to slide it onto my legs.

The pieces were sealed, primed, and painted like the helmet except the greaves were painted silver rather than green and red.

Step 8: The Chestplate, Thigh Guard, and Shoulder Guards (Do: Curass | Kusazuri: Thigh Cover)

I took measurements of myself as well as overlayed a photo of my body over the illustration to help with sizing/proportions. Once I figured out my pattern, I got to work (or continued to work).

The chestplate was made from two pieces of floormat foam glued together at the ends. These pieces were originally much wider but ended up being slimmed down due to me being unable to move my arms after the first test fit.

The chestplate is fitted over me similar to putting on a T-shirt. The shoulder guards rest on my shoulders and there's additional buckles at the sides and my waist. The buckles on the sides are made from rounding pieces of foam in the shape of a belt buckle.The foam straps were textured by using a ball of aluminum foil pressed into the foam.Velcro is used at the ends to help secure it in place. The belt along the waist has a plastic buckle that snaps together with a piece that velcroes over it to hide it.

The shoulder guards were glued at the upper corners to the main chest piece and follow the design of Boba Fett's actual shoulder guards. The grooves were made similar to the bracers.

The thigh guards were made similar to the shoulder guards just at a larger scale. They are velcroed at the ends and attach to the belt.

Holes were poked throughout the chest similar to the helmet for the added threading as well as googly eyes for rivets. An old soldering iron was used to burn lines horizontally through the armor to look like plates.

Step 9: Painting the Armor

Before I painted the chestplate, I added a simple box to one side of the belt to hold my phone and wallet. On the opposite side, I added a ring to hold the sword.

I printed a template for the Mythosaur skull and stippled a paint brush on top to copy the pattern to the armor. The bulk of the armor was painted with the same red and green color scheme except for the shoulder guards that were painted yellow and had smaller icons of the skull painted on. After the base coat was done, the yarn was threaded through.

Step 10: Weathering

The armor was heavily weathered.

Step 11: The Failed Sword

This was my first attempt at the sword. I tried to reuse the puzzle piece leftover edges that come with the floormat foam. The biggest fault was that I used a piece of wire and because the wire wasn't perfect, the sword in the end was twisted and just overall looked bad. Don't do what I did.

Step 12: The Actual Sword

The actual sword was two pieces of foam sandwiched around a broken fishing pole rod. Channels were made in the foam to accommodate for the rod and I used my rotary tool once again to do this. The channels were loaded with hot glue and the rod was placed in between the two foam halves. I took this foam blank and ran it along the belt grinder. This however eventually took too much and ruined the curve to the katana I was aiming for. I stuck with it however. More foam was glued around the rod to make the guard and handle.

The handle was wrapped in red vinyl and I followed this wrapping tutorial without the triangle spacers he uses.

The sword was primed and sealed like everything else. The blade was silver metallic with a hint of blue metallic acrylic paint for a slight blue sheen. The handle was weathered but the blade remained clean.

Step 13: Finished!

I used a karate uniform and a ski mask for the under-suit.

Step 14: Bonus Pictures

When I went to Raleigh GalaxyCon in 2019, Tsutomu Kitagawa, the wearer of the Millennium series Godzilla, was there and I got to take a couple pictures with him!

Step 15: Additional Tips and Resources

To help shape your foam, heat it with a heat gun. This will soften the foam and allow you to bend it to the desired shape where it will cool and retain that shape. Make sure to not heat in one spot or you'll burn the foam.
Use the heat gun to heat seal the foam. This will also help smooth out any fuzzies made when sanding.
Allow for contact cement to dry and become tacky before gluing pieces together.
Many of the techniques I used can be found over at Punished Props
Additional techniques can be found at KamuiCosplay, Lost Wax, Evil Ted, Odin Makes, and SKS Props.