Introduction: DIY Kids "Marvin the Martian" Costume

So my son’s costumes theme almost every year he has gone trick-or-treating has been about space or robots. This year he wanted to be a space alien. Over the last few weeks it morphed into the "Looney Tunes" character "Marvin the Martian."

So after studying several images on the internet, I decided I could make the helmet and what I call the "Martian Battle Tutu" out of EVA foam. Let me begin by saying I like to tinker, but I recognize my limitations and despite watching several YouTube videos on making EVA helmets, I am truly a novice at the art. I do however like to accessorize my projects, mostly with LED lights. My one key reason for adding LEDs to projects is that it helps identify my son in a crowd of kids and also adds some degree of safety that others can see him in the dark...and of course it looks cool.


Helmet and Tutu

  • A helmet pattern (I recycled a Star Wars helmet pattern I bought last year)
  • EVA foam about 1 - 25"x25" sheet is enough for 1 helmet (Harbor Freight has a pack of 4 for $10)
  • 1/4 inch foam sheet for Tutu - (Michael's Craft Store)
  • 9"x12" black felt sheet (2 sheets) to line finished helmet
  • Razor blades and a blade sharpener (disposable work fine - Harbor Freight has these cheap)
  • Heat Gun (helps shape and seal EVA foam)
  • Rubber cement (1 project consumes about an entire 4 oz. bottle)
  • Water soluble caulk for kitchen and bath
  • Paint (for this project I used Rust-Oleum 2X UltraCover paint + primer - works well on plastics
  • Car Wash Sponge (get this at Dollar Tree store)
  • Personal Patience

LED Lights

  • White, Green and Red LED strip lights
  • Solder iron and solder
  • Hot glue gun and glue
  • Wire cutter and stripper
  • 20 gauge wire (about 2'-3' max.)
  • 2 rocker switches (low profile)
  • 9 volt battery
  • 9 volt battery terminal connector


  • Red full body suit
  • white sneakers
  • White gloves
  • Lycra face mask
  • Belt

Step 1: Have a Plan

So I started out with a Poe Dameron helmet pattern I picked up a year or so ago. I modified the sides to fit with Martin the Martian photos I studied on the internet, crafted my own visor and back trim pieces. For the tutu portion, I cut out a circle within a circle and then cut the remaining "doughnut" into segments. I only needed one for the pattern and cut this on cardboard. Note: Before cutting out any of hte patterns, I line the back with duct tape. This adds rigidity to the piece and allows me to get a better transfer of lines and in some cases (the tutu) use the piece as a cutting template. For the topper on the helmet, I cut these free hand.

Step 2: Cut Out and Assemble the Pieces

This is the most challenging step in the whole process, get through this and everything else is down hill.

So once the pieces are cut (again, highly recommend you watch YouTube videos for all the little tips and tricks) you dab rubber cement along the edges of the cut pieces, let the cement cure (dry completely) and then press the pieces together.

Per the YouTube Makers, keep the razor blade as close to perpendicular as possible when cutting. Clean edges help with assembly.

My Tips & Tricks:

1. Form fit all the pieces as best possible before cementing. Use the heat gun to soften the foam and then shape it to the point sides fit along the seam of adjoining pieces. The better the seam before cementing, the better the end product.

2. If you assemble the pieces while any portion of the cement is wet, that area will begin to pull apart. If this happens, let it come apart, re-dab cement on the part, and let it dry completely, then press together again. If it still wants to come apart, use masking tape to hold edges together and let it sit for a day or two to allow the cement to cure more.

3. The Kitchen caulk is to fix mistakes. I struggle with the registration points on the original pattern, so per YouTube videos, my go to is caulk.fix what you can then use other products at the end to hide dimples and cracks. A glass of water to wet your finger when working with caulk helps get smooth surfaces. The bad news is caulk shrinks, so if you have to fill a hole, expect to fill it a few times to eliminate the dimple.

4. A metal ruler helps with getting straight lines to be perpendicular when cutting foam. Using cardboard and duct tap to make patterns makes a good rigid guide when cutting rounded areas.

Step 3: The Crown, Visor and Tutu

The crown was cut freehand using a straight edge. I used 1/2" foam and cut two 1" squares to make the post to the crown. I used a 2"x4" piece as the crown it self and measured to ensure the post was in the center. Cement these pieces together. I wanted to crown to light up so I added the white LED strips to this and then covered with the car wash sponge. The crown is wrapped in orange glitter sticking foam (Michael's Craft Store). I also used a skewer stick to temporarily connect the crown to the helmet before final connections were made. I had to run the wires from the crown into the helmet and the skewer helped me place the holes needed through the helmet in the right locations.

The Visor was drawn freehand and made of a single piece with no seam. The key here was I needed a solid place to locate the rocker switches. I decided to use a 1/2" PVC pipe to cut a circle in the ends of the visor. Keep the pieces you cut out, cut around the switch, and make small, thin cuts through the helmet to run the wires.

The Tutu is made of nine wedges in all. I used the 1/4" foam sheets to make the panels, and 1/2" EVA foam blocks about 1"x2" to make the belt loops, with a 1/4" strap to hold the belt loops in place and give a slight bend to the panels. Eight of the panels are made with belt loops, the last panel is connected another panel with 1/4" straps so it covers the belt buckle area without an obvious gap.

My Tips & Tricks

1. Always test electronics before final assembly! I never like to have to go back and re-fit stuff so I have learned over the years take your time, make the right connections and test before making anything permanent.

2. LED lights come with glue on the back, but this glue doesn't stick well to EVA foam. Draw a line with a marker and place cement on this line, let it dry and anything that has glue will immediately stick to the cement and hold tight.

3. On the Tutu panels, I had an old belt I that was broken, so I cut about a 3 inch piece to use as a spacer between the 1"x2" belt-loop pieces. Also, tug on the underneath strip to give the panel a slight curve. Do this before mounting it to the dry cement on the panel..

Step 4: Painting, Fixing, Mounting and Connecting Electronics

I got started on my son's costume late this year. I usually start planning around August 1 and have good ideas formed by Labor Day. This year we were really busy so got we got started about the end of September. Less time means more short cuts.


Instead of priming the pieces, I opted to try using a paint and primer in one. I chose Rust-Oleum 2X UltraCover. I am happy with the way the painting turned out, clear surfaces and good adhesion. Due to limited time, I covered areas that I know will be visible and opted to let some areas go unfinished (see belt wedges).


The painting highlighted some imperfections that the caulk did not fix. My go to solution here was green glitter glue. The glue filled the imperfection and the glitter distracts from the seams and dimples.


Because the crown has electrical wires, I didn't want anyone to tug on the crown and pull it off. I opted for a 1.5" 10-24 cabinet screw with 2 washers and nut to provide an anchor for the crown. The washers will prevent it going in or out, and the screw shank provides greater surface area for mounting. I started with cement, but that did not adhere to the screw shank well enough, so I went back with hot glue which also go into the threading.

Connecting Electronics

So I'm a big guy and my hands don't fit into small spaces well. Knowing this, I opted for longer leads on the electronics and hot glued down the excess wiring. With everything connected and tested, the last part was to line the helmet with black felt. This adds to the illusion of Martin's face.

The crown is made of white lights under the car sponge foam. It lights up really well in the dark. With the crown lights, there are green LEDs that help back-light Martins head inside the helmet.

My son likes to say the phrase from the cartoon "Oh, you are making me very angry". So I thought it would be fun to add a band of red LEDs so he could switch between green and red lighting when using that phrase.

Last, to hold the battery, I created a small pocket in the felt lining of the helmet at the end. Cut a small piece of felt about 3 times wider than the battery, and use fabric glue (I think it is also known as simple stitch) to hold the pocket in place. The fabric glue dries quickly so work really fast, it's fairly solid in about a minute.

My Tips & Tricks

1. Hot glue is excellent for mounting the wiring to EVA foam. Caution, if you mess up and need to remove dried glue, EVA is going to come off in the removal process. Solution: Start with a small dab of hot glue to hold parts in place (like tack welding) and once you are good with the mounting, go back with more glue to add coverage or more anchors to the wires and parts.

2. Cement is not always the best option. For parts that must fit into tight places or have weak supports, hot glue helps add rigidity and gives you time to make adjustments before the glue cools down. I used hot glue to mount the crown to the helmet and secure the foam supports around the side switches

Step 5: Lessons Learned

While I feel like I got a late start to making my son's costume this year, the reality is that I had more than enough time. I rushed some processes when I could have taken a little more time. Of course, the bright side of the faults I encountered is that I got to experiment with my own tips and tricks to fix the flaws.

Working with foam is incredibly easy, and I cannot thank all the Makers kind enough for sharing their talents on YouTube and the various websites. I probably watched some 4-5 hours worth of different videos - not because I had to, they were really good and educational in so many ways.

If you even have an inkling of playing with foam costume elements, trust me - do so. Like I said the cutting of patterns is the hardest, everything else is just plain fun times. Oh, and if you really want to make it your own, do like I did and accessorize in ways only you can.

Halloween Contest 2019

Participated in the
Halloween Contest 2019