I love a flat mask! In particular, I love a flat mask with a hard, instantly-recognizable silhouette and a protruding human face. That's a pretty specific category, and there's probably some early-childhood-development explanation for my interest, but making masks is way more productive than trying to unpack the origin of my fascination. Would it be more rewarding if some weird friend of my parents once scared me with a hairdo shaped like Quick Draw McGraw? No.

A few years ago I tried it with a flat, pitch-black rabbit mask. Basically a human face set into a Bugs Bunny silhouette, with just enough highlights to make the face look extra weird. It's a cool mask, but my first foray into flatness and smoothness was not as refined as it might have been!

I followed that up with the average bear, which was constructed the same way but shaped like Yogi Bear. Mainly I wanted to refine the technique, and I did feel it was a significant improvement.
The big artistic difference here is the paint job, a trompe l'oeil that looks like Yogi's cartoon face when viewed straight on.

When I decided to revisit the flat-mask concept again, I aimed for simplicity. The stop sign is only two colors, and an absolutely unmistakable shape. The human face on this one is essentially featureless.

For this mask, you really only need to make two items: a cast of your face, and a big octagon! The rest is just refinement.

Supplies

This mask was built from plaster gauze, corrugated cardboard, masking tape, duct tape, paper mache, and paper clay. Tools include scissors, a box-cutter, and a protractor!

Step 1: Starting to Stop

Using the plaster gauze, I made a cast of my face. If you've never done this before, it's pretty much the easiest thing in the world (especially if you have an assistant, but I usually do it on my own). It can be messy though, so wear your crafting clothes and put down a drop cloth, if you've got one. Cut up your plaster gauze into strips, grab a bowl of water and a mirror, and go to town!

You'll want to smear your face with petroleum jelly, or coconut oil, or some other lubricant that will aid removal of the plaster. Then moisten a strip of plaster gauze and lay it directly on your face. Avoid your eyes and leave yourself a space to breathe through your nose, but otherwise, just keep doing that until your face is covered. Be mindful that the edges of the cast need to be just as thick as the middle! They've got to be strong and hold their shape when you lift it off.
You have to wait for it to dry, but it needn't be perfect. You can even hasten the process with a blow dryer, if you're careful. The cast just needs to be sturdy enough to remove from your face, and then set it aside to cure completely.

Step 2: Make a Pie!

Since I discovered right away that making this mask the actual size of a stop sign would be too large, I decided to kind of wing it. I looked in the mirror, held my hands out from the sides of my face and thought, okay, about this big. It wasn't the most precise measurement, but we all have different body types. This was the size of stop sign that I needed, but if you need a bigger one (and you've got bigger cardboard!) all the steps will be the same. You'll just need more materials.

My supply of cardboard for building masks is usually limited to whatever boxes I have received as mail, so they don't tend to be very large. On this occasion, my partner had recently replaced the Shop-Vac, so I had a slightly larger box on hand, but it still wouldn't be big enough to make a really big, unbroken stop sign.

To create a perfect (ha!) octagon my plan was simple: make a large circle. Then bisect that circle through the center, and again at a 90 degree angle from the first diameter line. Then twice more, at 45-degree angles from the other lines (that's where the protractor comes in handy!)

Now you have a big circle divided into eight equal pieces. Like a pie. Those eight lines all intersect the outer edge of the circle, and if you draw straight lines from one intersection to the next, you end up with an octagon!

There was just one problem: I didn't have a piece of cardboard big enough, so I was going to have to use two piece of cardboard joined together. In theory, that was fine, but the joining line was never going to be invisible. One way or another, it would show through in the finished product! That's what I had to work with though, so I duct-taped my two pieces of cardboard together, made my circle, and created the octagon (using the join as one of the lines of bisection).

Step 3: Can't Stop Won't Stop

Once you have a face cast and an octagon, the next big decision is figuring out how exactly you want them to fit together. Is your human face right in the middle? Is it high on the sign, or low? How far out from the sign do you want your fuman face to protrude? These are all personal choices, and can be affected by your specific body. If the sign is set too close to your trunk, and too low on your head, it can inhibit your movement!

I personally wanted the face slightly below center, and I like to set my flat masks so that the flat surface rides just in front of my ears.

Attaching the mask to the flat can be a little tricky, because the human face isn't really built for that. If you, like me, have some kind of hairline and jawline, then your face cast probably stops at both of those places– and it doesn't make a straight line!

On me, that means the area in front of my ears, where the sideburns grow, is the terminus of my face cast. The 'deepest' part. That's what gets duct-taped to the flat, and then paper mache strips are laid over it to make a secure connection. That leaves a lot of open area above the forehead and below the chin; these will need to be filled in with cardboard strips and papered over, to make the face complete.

As you build it in, be sure to try the mask on your face at every step! You don't want to underestimate the size of your forehead, or choke yourself below the chin!

To make the mask wearable, I decided to build an elastic strip into the back of the piece. I dug two small holes into the back of the cardboard, glued in the ends, and then packed them in with paper clay. In time that elastic is going to fail so I've set myself up for disappointment, but I chose a more streamlined look over good sense.

Step 4: Stop and Smell the Ridges

Once it's all assembled, simply cover the whole thing with paper strips until you're satisfied with its structural integrity. Let it dry thoroughly, and sand it down as smoothly as you can.

Originally I had thought of this whole mask as smooth, just the hard flat lines of the stop sign curving into the human face at the center. Building it from two pieces of cardboard, instead of one, necessitated a change – not to hide that line, but to utilize it. If the transition from the flat surface into the curved surface involved some sharp 'metal buckling' then the design flaw could easily become part of the actual design.

Paper mache clay will allow you to build convincing bends and folds around the facial protrusion, and perfectly curate the transition between flat and face. I also used paper clay to alter the shapes of the eye opening, giving the mask something of an expression.

Step 5: Stop Til You Drop

The paint job for this mask is pretty simple, being only two colors, but it's also got to be very fussy to make the lettering look natural in spite of the shape.

The best way to do this would be to project the letters onto the mask using an opaque projector (like an old-timey classroom overhead), and trace them onto the surface. That would give you the precise block lettering, perfectly stretched over the curves of the human face.

But I don't have an opaque projector, so I did it all by hand.

First I drew in the white border around the outside. I looked at real stop signs and blocked out where all of the letters needed to be, and drew them freehand. If you, too, are comfortable freehanding, it is a viable solution, but it may take a while. I did a lot of looking head-on at the face, squinting, turning it this way and that, and gradually making tiny adjustments until I felt that I had it looking right. Then I painted everything else with a white base coat.

If the mask is being worn, then a person standing behind the wearer will always see the back of the stop sign, so I painted it black with a sheen of silver over the top.

The rest is filling in the blanks. Paint the red parts red, and the white parts white! It takes several layers to make it really rich and bold; you've come this far, don't skimp on the finishing.

Step 6: Red Means Stop!

Do you love it? Oh, stop!

I cannot offer you an explanation for why I thought I needed this mask, but it's exactly what I wanted. This technique is applicable across all three of the flat masks I've made, so if this Instructable gives you any ideas, I'm sure that they will work! It's a weird, inherently creepy look that I believe you will enjoy.