Rex - Helmet and Collar Tutorial

Hello and welcome to this 6th cosplay tutorial on my Rex cosplay! This time, we will take a look at how to do Rex’s helmet (and the collar that holds the helmet).
Rex is the main character of the video game Xenoblade Chronicles 2 on Nintendo Switch. He mostly wears his helmet on his back, attached to the collar.
Here are various reference photos coming from the concept art and some screenshots from the game. Some key elements to not forget are shown in the following pictures:
The helmet itself is basically a big sphere on which your head to fit it. For the record, I can fit my head if I remove the wig (because I don’t want to damage the hair spikes on it).
To build a sphere, I recommend using 2 half-spheres (to serve as a pattern) that are big enough for your head. You can find some at stores like Michaels (in their floral department).
You can then bind them together to form one big sphere, then sand all the little dots on it using sanding paper (steps 1 and 2 in the next picture). Then, we will form a tape surface on which we can draw all the details of the helmet shape! First, you can cover the sphere with plastic or aluminium foil (step 3). Then, you can cover the whole sphere with tape, as shown in step 4 (I am using duct tape). It is very important to mark the middle point of the sphere: I am doing it in step 4 with a Sharpie marker.
Once the sphere is covered with tape, it is time to draw more “orbits” around the sphere: once every 45 degrees: you should then have 1 horizontal orbit, 1 vertical orbit and 2 oblique ones. They will be useful for marking the perfect center of the sphere on each side and for removing down the tape later.
On each orbit that you are tracing, make sure to create registration marks. They will be super useful when uniting all pieces together and aligning them so that their union is perfect.
Then, it is time, using a compass, to trace the following:
  • the front hole for the helmet;
  • the 2 side holes on each side of the helmet.
Make sure you have circle sizes that fit the game’s proportions.
You will also need to create a large opening for Rex’s head, and even more, since there is a big golden large extension at the bottom of the helmet. You will need to trace it on the sphere.
Then, to not lose yourself in the various tape pieces that you are able to cut from the sphere, you should identify each 45 degrees slice (those caused by the orbits) using numbers. You can also write down, on each orbit edge, what is the adjacent piece’s number and also where the top and bottom are located. You may be inspired by what I did in the photos below.
Once every piece is identified, you can start removing all “bottom” pieces of the sphere carefully by following each orbit with a knife. You also need to exclude the windows and head holes from the patterns.
The following photo shows what you should get after this operation. The bottom of the 2 side holes are clearly apparent. The bottom of the front hole is split on both sides.
Then, you have to do it for the “top” of the sphere. The 4 left bottom pieces in the next photo are the top sphere patterns.
You should then all have the patterns you need to create the sphere. There are 10 pieces in total.
Here is a close-up on 4 pieces for the bottom half of the sphere. You can clearly openings made for tracing registration marks on EVA foam. These openings were made using a sharp knife.
If you want more durable patterns, you can transfer them on thick drawing paper first. This is what I did. Then, you can transfer the pattern onto 10 mm EVA foam. The helmet is quite thick, so you need 10 mm foam. You can start with the bottom pieces first if you want, as I did (shown in the next picture).
Then, following the numbers and instructions written on EVA foam, and not forgetting the registration marks, you can safely glue all pieces together. You need a very strong glue for this for a solid result: I recommend Barge contact cement.
You may proceed by taking your time and slowly gluing each edge, registration mark by registration mark. At the end, you should get a very result like this:
You should let this half of the sphere rest for a couple of hours before handling it again: this is for letting the Barge contact cement dry completely, forming an ever stronger bond.
If you have done your work right, there should be no gap at all. If you need to make some fillings, you can use Kwik Seal or foam clay.
Now, let’s move on the top half of the sphere. This part has more foam on it than the bottom half (no big hole for the head). Using our patterns, let’s transfer them on 10 mm EVA foam and let’s cut them. You should have this as a result:
Then, let’s assemble all 4 pieces together to create the top half of the sphere, just like you did for the bottom piece.
Then, let’s rest the 2 halves together so that the Barge contact cement can fully dry. You may use the half-spheres you have bought for making the pattern as resting pieces: you can slightly push and force the EVA foam sphere halves into position, so that the desired shape will be fully respected when the contact cement will be fully dry.
Then, it is time to unite both halves together with Barge contact cement, resulting in this nice-looking helmet base! Let the whole thing dry for a few hours.
Then, it is time to add the other details. Let’s start first with the gear circles that surround each helmet’s window hole. You will need to measure the diameter of each hole and get the desired width for each gear (excluding the teeth). You can then transfer them onto 5 mm EVA foam.
I was fortunate enough that 1 gear for the side hole fits into the gear for the front hole. Less waste, we like it! You will need 2 gears for the side holes though!
To ease your foam cutting experience, I recommend you a hot knife! This is the first time I have ever used this tool! It is especially useful for working on angled cuts and bevels!
First, let’s cut the rings from the foam.
You might have noticed that the edge of each gear arrives flat on the helmet base. This means: progressively reducing the height of each ring from the inside rim to the outside rim. You can then proceed with making an angled cut using your hot knife to remove the excess foam from the back of the rings.
It is very important to make this operation from below the ring, as we want to keep the front and visible surface untouched and smooth, but with an angle.
You might need to add foam clay at some places where the knife has removed some foam from the surface, you will then need to sand the foam clay excess later when it will be dried to form a perfect smooth finish.
Then, once it’s done, you have 3 angled gears!
Let’s pause our work on the gears for now to work on the vertical bars on Rex’s front window. Using the diameter of the front hole as a reference, let’s build a circle pattern on which we can cut away all the spacing. We can then transfer the pattern on 5 mm EVA foam and then make sure that the piece fits the front hole and front gear.
After that, we need to add the window itself. You may wonder: what is the blue material for the window? I have decided to go with a zipper pocket bought at Dollarama that is exactly of the right color! It is a super cheap solution that is very fast to use! You could also have chosen to go with transparent worbla and use transparent paint to do the same effect.
You will then need to cut big circles in the zipper pocket that are 1-2 cm bigger than the hole they are destined to cover. It is recommend to create small openings around each circled piece (see the left photo in the next picture) so that you can slightly flex the edge without distorting the entire circle.
When you are ready, you may install each window on the inside of the helmet. You may use Barge contact cement to fix each piece. This way (installing it from the inside), you are (and should be) making sure that nothing suspect is visible from the outside.
Since we want a helmet that looks perfect on the outside and very good on the inside, let’s cover the (a bit ugly) edges of the blue window with a 2 mm EVA foam ring that has exactly the same dimensions as the gear on the other side of the helmet. Use Barge contact cement to fix it in place.
You will have to repeat this operation again for all windows.
There is one small circle (2 small layers of 2 mm EVA foam to put) to install at the center bottom inside the helmet. You can use our favorite glue, Barge contact cement, to install it.
Then, it’s time to go back on the 3 gears. We need to install all their teeth. First, let’s identify their exact location using a pencil / Sharpie marker and a good angle protractor (using a pattern if necessary), since there are 6 teeth on each gear - 1 every 60 degrees.
You can then remove the EVA foam where the teeth are: we will install our own foam teeth there.
To form the teeth, you can use 6 x 3 = 18 rectangles of 5 mm EVA foam. You can put them in place with Gorilla Glue gel (since you will have to slide each tooth into their cavity: it’s not possible to slide one piece into another when using Barge contact cement).
Once the teeth are installed, let’s install all gears on the helmet. Now is the time to use the force of the Barge contact cement to our advantage!
You should have a nice result like this at the end:
The final window to install is the front one! I suggest that you glue the blue plastic piece from the zipper pocket directly on the back of the vertical bars piece and then, glue the sides of the piece to the sides of the front hole and/or front gear. Since this could be a fragile part of the helmet (you don’t want to front window to fall on the ground), make sure you have more glue there - add more if necessary.
Now, to the 2 horizontal bands on the top of the helmet! First, let’s measure the distance you have to cover on the helmet for each band. In my case, it is 26 cm. Second, let’s determine the maximum height of these triangular bands, which is 5 cm for me. This is important to determine what type of angled cuts we need to do after.
We can them determine which cuts will be necessary if we build the same of the triangular band with 10 mm EVA foam. It gives the shape given in the final bottom pattern in the next photo, with the barred sections marking the foam we have to remove.
Following the final pattern and the desired length from the last photo, let’s cut rectangular pieces of 10 mm EVA foam. Then, let’s remove the foam to create the angles using a hot knife to cut most of it, with a Dremel to finish the job and give it a smooth finish. You can see this process in the next picture. The rightmost image is the final result when joining both pieces together from their largest cut section.
Then, to allow the band to curve around the helmet’s top without creating unexpected distortion, let’s remove triangular foam parts from the piece. By gluing together both sides of the created triangles, we will get the desired curve we need. Use a sharp knife to remove the foam.
Then, after using Barge contact cement to unite the sides of all triangle holes together, we have a nice curve!
All that’s left is to glue both curved pieces together from their largest cut angle, using our preferred Barge contact cement, which will give the curved triangular prism we need. Then, let’s glue this prism to the top of helmet. Make sure you nail down the location of each triangular prism with a Sharpie marker and let’s glue using contact cement!
Now you have it: the golden band glued on top of the helmet! Please remember that you have 2 to make.
If you wish to remove any crack caused by the triangular cuts glued together, you may apply multiple layers of Kwik Seal to make them disappear.
Now, if you look at the reference pictures closely, there are small holes on the helmet at equal distance from each other and close to the top bands.
You can use a Dremel with the cone head to make every single hole. Please note that there might be a small buildup of foam left at the middle of each hole. You can remove it with tweezers.
After gluing the top bands, there is a still a big hole at the front and bottom revealing the inside of those bands. We need to install lights (or something resembling lights) at these locations, both at the front and back of these bands.
You could use LED lights and build a circuit for this. For me, I have decided to simulate lights without doing them. I have built 4 big balls of foam clay simulating a light source and I have installed them at the end of each band, which blocks part of the hole. For blocking the rest, I have built custom EVA foam shapes: you can see the pattern at the middle of the next picture that blocks the space above the foam clay balls.
Now that this is done, it is time to build the big collar-type gold angled portion of the helmet at its bottom. It is quite a big piece, which is 2-3 cm under the edge of the helmet at its front and almost 6-7 cm under the edge at its back.
Just like the top bands on the top of Rex’s helmet, I have decided to create triangle openings that cover half of the portion’s height, since the piece will have to curve.
This gives the following pattern (see the next picture). Then, I have decided to use a 5 mm EVA foam base and transfer the pattern on it.
Then, it is time to close the triangular gaps using Barge contact cement. As you can see in the next picture, there is a curvy effect starting from the middle of the piece’s height to its top.
However, this 5 mm EVA foam piece is only the base for another construct: we need to build angled bands that will form a clear edge at the middle of the base. What is also important to know is that the base is thinner at its horizontal extremities and larger at its center. We then need 2 different patterns depending on where we are on the band.
To simplify things, I recommend that you cut 4 pieces of EVA foam. There will be 2 per half of the golden collar piece. One end must be thinner (following top pattern from last photo) and the other end must be larger (following the bottom pattern from last photo).
Here is how the pieces should look like after being transferred on 10 mm EVA foam, angle-cutted and sanded with the sanding head of a Dremel. The next photo only shows 2 pieces (you need to make 4).
Then, let’s assemble these bands together using Barge contact cement and let’s fix them on the 5 mm EVA foam base we have done before.
This is how the golden band collar should look like after all pieces are glued together.
You may need that there is a gap at the back middle of the collar. It’s ok for now, but you will have to plug it later with either EVA foam scraps or foam clay.
Here is how the golden collar band looks on the side. Notice how it reaches to the front of the helmet.
The golden band collar has this shape at its front extremities. Let’s make a pattern on it and let’s start working on this.
We will need to remove some EVA foam from it to make way for a flat surface that will host the shape we have just made a pattern for. To do it, let’s carefully mark what we need to cut, then use a sharp knife to slowly remove the foam. You may finish the job for having a smooth surface with a Dremel (cylindrical sanding head) and/or foam clay with another Dremel application.
For the shape itself, you may use 2 mm EVA foam to form the base (photo 2 below). Then, you may prepare 2 oval shapes (photo 1) and sand all their sides with a Dremel to create a round shape (photo 3) for these ovals. You can then put these oval shapes at their designated location on the 2 mm EVA foam base, with a small 2 mm EVA foam band at the middle to finish the shaoe.
Then, let’s glue it to the end of the gold collar with Barge contact cement. After an optional bit of Dremel sanding to make sure all sides of the base are equal and do not go over the collar under it, you should be all right!
You only need to repeat the same thing for the 2nd identical shape you have to make for the other side!
Now, after gluing the big golden collar to the helmet, you might have noticed that the thickness of the collar is not what it is in the reference pictures. Also, you might have an irregular inside surface for the golden collar (waves or folds on the 5 mm EVA foam base) after gluing it to the helmet.
To remedy to these problems, here is the solution: add an extra 10 mm EVA foam piece to the inside of the collar, which will increase the thickness of the collar and hide the imperfections on the 5 mm EVA foam base.
Here is how it looks with the extra padding on the inside of the golden collar: much better!
Oh, and you can add holes to the outside bottom and top of the golden collar, reusing the same techniques that you have used on the top of the helmet near the angled golden bands.
You can then add the finishing touches to the helmet. There are small dots on every gear tooth. You can mark their location with a Sharpie marker, then glue tiny spheres of foam city on them, using Gorilla Glue gel.
Once it’s done, then it’s time to finish the helmet and all pieces by priming and painting them. We will start by first adding 3 layers of Flexbond on all the EVA foam surfaces, both outside and inside the helmet. You will need brushes of various sizes such there is a diversity of spaces to work on, large and tiny.
Then, once all layers of Flexbond have been applied and have dried, time for the paint! Apply mutiple layers of blue paint (I have used Cobalt Blue from Pebeo) where it is needed.
You can then proceeed with yellow ocre as the base for the golden parts, then a mix of 50% metallic gold and 50% metallic silver for the finish final color.
The small dots on the gears teeth are 100% metallic silver.
Then, it is time for details and shading! You can start with darkening every small hole you have done on the golden collar and the top of the helmet. Then, you can apply black paint at the edge of the golden parts, then in the depth and cracks to make small parts stand out (like the oval modules on the golden collar).
You may also apply more dark paint on the golden portions that hug (or are very close to) the windows, which gives a lot of depth!
I have also slightly darkened the tip edge of the golden collar and bands to highlight the angles.
Also, please notice that I have painted yellow the 4 light spots on the top of the helmet.
Then you have it! Rex’s helmet is mostly complete! Congratulations for your work!
Now, you may ask yourselves: how will Rex’s helmet hold on you? The answer: by creating a collar that Rex wears around his neck and by creating a mechanism for attaching the helmet to this collar!
Let’s start first by creating the base of the collar. Sadly, I don’t have WIP pictures for the EVA foam base under the worbla that is shown in the next pictures, but these steps to build the base are quite simple:
  • Determine the size of the collar you want to have. Rex’s collar should hold a little bit on the inside of his shoulders.
  • Then, using 10 mm EVA foam, you can cut a foam piece. Make sure this piece can go all around your neck, leaving an opening of at least the width of the neck in front of you.
  • After that, using 10 mm EVA foam again, cut a foam piece of the same length, but smaller in width. You will have to glue the piece to the middle of the other piece.
  • You should then have a EVA foam collar of 20 mm in height.
  • To the front of the band, there are 3 holes on one side (female ends) and 3 squares on the other side (male ends). You will need to carve 3 squares from one side, using a knife. For the other side, you may cut 3 small 10 mm EVA foam squares and glue them to the extremity of the collar.
Finally, it’s time to cover this EVA foam base with worbla. Cut a piece that is big enough to cover both sides, then simply heat the worbla, put in on your EVA foam collar and press in all corners, cracks and holes (using sculpting or pointing tools if necessary) to make sure the collar has the same details as when it was only in EVA foam.
After then, it’s time to prime and paint using the same tools, techniques and colors we have seen before, with some differences:
  • You can use super thick gesso to prime the worbla piece. Since worbla does not flex, Flexbond is not needed.
There are small dots to the top and bottom of the collar’s middle band. You can do that with either small Googly Eyes or foam clay. I have chosen to go with Googly Eyes (as I didn’t know the existence of foam clay at that time).
Rex has a small blue fabric module attached to the bottom of the collar. We will then need to do it! Let’s start by first making the pattern of this piece. You may refer to the references pictures at the beginning of this tutorial for more information.
This section is quite thick (just like Rex’s skirt and blue top jacket, as shown in their tutorials), so what I recommend is building a 2 mm EVA foam piece and covering it with blue fabric.
Using the pattern from the previous picture, I have cut myself a piece of 2 mm EVA foam and fabric (with some extra fabric padding to cover all sides). Then, you can pin the fabric to the foam and sew it with a sewing machine.
There are golden parts on this piece as well! (gold, gold on Rex everywhere!) Let’s use our pattern for the piece to determine the length of the golden bands at the bottom of the piece (picture 1 in the next photo)
At the extremity of the piece (3 and 4), there is a mechanism for closing the collar, which uses 2 holes. You can build this mechanism (that does not seem to work) using 10 mm EVA foam. You will have lots of fun with a sharp knife making spheres and lateral holes on this tiny surface! (yes, seriously!)
To create the effect of having tiny circles stand out of these piece, you can cut circles in the foam pieces, gently push them out halfway and gluing the inside to keep them in place (photo 4).
Then, it’s typical priming and painting time for all these parts! (photos 2 and 5)
Then, you can glue the golden parts to the base fabric piece using hot glue and/or Barge contact cement. Please note that you have 2 long golden bands to glue (both inside and outside the collar) and that nothing from the base should be visible between these glued bands.
Then, it’s time to glue the blue piece to the bottom of the collar. I have used Gorilla Glue gel for this, as the upper part of the the blue piece still has the 2 mm EVA foam exposed and the underside of the collar also has the EVA foam exposed. Barge contact cement should work too.
And then, you have it, Rex’s collar!
Now, how in the world we will attach the helmet to the collar? First, I wanted to try magnets, but I was not comfortable with this idea and playing with strong magnets can have unexpected consequences on your health and environment. I have found a simpler solution instead.
Look at how the door closest to you works: it has hinges for holding the door in place and allowing you to move and open it. This mechanism can work for holding the helmet to your body!
First, let’s build the hinges! The trick is to cut multiple 10 mm EVA foam pieces and glue them together (at least 3 of them) to form something thick and solid enough to form a hinge part.
For the hole itself, you may start cutting it with a sharp knife, then proceed with a dremel to smooth all sides.
Here is a quick test of this mechanism showing that it works! Obviously, what is in the middle will be more solid than a pencil at the end!
Then, now you that you are convinced, let’s build a complete hinge! All the steps (and the proof that it works) are in the next picture.
Let’s attach one end to the collar (using extra foam padding left and right to remove any gap). Apply a lot of glue (Barge contact cement in my case) since this piece needs to be solidly attached and will hold the helmet (which is not heavy but still, better to be safe).
Following this, let’s attach the other end to the back of the helmet’s golden collar! Testing that the system works (and living this magic moment) is very important!
I have used heated worbla scraps to form a thin pencil-like shape like you see in the next picture. This will hold both sides in place solidly. After than, you can prime and paint all hinge parts and you should be done!
Now, leave it like that and the helmet will fall from your back since nothing binds the collar to you. We need to come up with something. We need to attach the collar to one of Rex’s jackets: let’s use the brown bottom one for this goal. 4 anchor points on each piece should be enough for this. You can use the vinyl around Rex’s neck (for the jacket) and the inside of Rex’s collar to sew and/or glue the 4 anchor points.
I have found these tiny backpack-like clips to be super useful! I have found them in the beads/jewels section at Michaels. You should use solid straps like those to the left of the left picture below: using vinyl (faux leather) is not a good idea as it can stretch too much when under some strength.
This is how the male half of the clips look on the brown jacket. You should have appropriate female halves glued on the inside of Rex’s collar.
Then, you can test the system works (you might need someone to attach the helmet to the collar for you).
After all these efforts, you may now rest on your laurels: you have finished Rex’s helmet and collar! Congratulations! Following is a nice photo of this result from Geeks Are Sexy!


That concludes this tutorial for Rex’s helmet and collar! Stay tuned on my cosplay accounts named GDICommander (Facebook and Instagram) for more tutorials, photos and updates on Rex and my next cosplays!