I originally had the idea for this costume for Halloween in 2015. I heard there was a Halloween party, and a month before it started, I realised I needed a costume. Lo and Behold, I came upon this after a quick google search. This was all done within a week or two of the party, so I do recommend having a good time frame to start the project. That way, you can add whatever detailing you like.
This costume requires the use of the Pepakura programs, so if you need them, links will be available at the end of this instructable. My own Pumpkin head utilizes some little LED lights for a cool spooky effect, however this is completely optional.

Step 1: Materials and Equiptment

The Model:

To get the model of this pumpkin head, head to Papercraft’s page on pepakura.ru (link at the end of the instructable) to get the model. Please note: this page is in Russian, and may require a translation to read. There are three to choose from here, so choose the one to your liking (I chose the third model)

The Programs:

In order to view the model, you’ll need to download the Pepakura Viewer program. The link for this and the program below are both available at the end of the instructable.
To resize the model to fit your head, you’ll need the Pepakura Designer (however, you must pay for this program, but ask around and you may be able to get someone to do it [or buy it] for you!)

Equiptment:

A computer that can run both programs
A printer Scissors or other cutting tool Ruler, if required
Extra space (it can get a bit messy!)

Materials:

Sheets of paper (this can vary depending on the size of your pumpkin) and Cardboard (enough for all the pieces) OR cardstock (amount varies on model size)
Gluestick
Masking tape
Paper mache (the paper and glues)
Hot Glue Gun
Mesh
Paints and other decorations
2x small LED lights (optional)
Wires to connect the battery and lights (optional)
A battery and battery pack (optional)

Step 2: The Process: Adjusting the Model

Firstly, download the model and program(s). Once you have done this, open Pepakura Designer to adjust the model. To do this, first open Pepakura designer. Than go to FILE > OPEN. Choose your model. Now select 2D MENU > CHANGE SCALE > SET SCALE… [see image 1]

Here, you’ll be able to change the size of the model. Please note, that one value will change all values. It is best to change the Width for this model. My own mask was set to a width of 400mm (from his left cheek to his right) and provided adequate room for my head, however this value may change depending on your own sizing.

Once it has been scaled, you’ll notice the pieces on the right hand side have changed. You’ll need to reorganise these to fit the pages nicely, like in Image 2. Please note, that there will be overlapping pieces!

Organise them as best as you can, and to try and have as less pages used as you can (save yourself some paper). You can choose to print this in colour or plain, as seen in the images to the right and above, and this is completely optional. Because I was painting the model I removed the colour. This can be done by selecting the Set Materials to Face option, as shown in image 3. Note: It is also easier to see the fold lines when the colour is removed.

Handy Tip!
Adding an Edge ID to your model can help the costuction of the model, and is highly recommended! Do this by going to 2D Menu > Show Edge ID [See Image 4]

Once everything it to your liking, go ahead and print the model!

Step 3: The Process: Constructing the Base

Once you have all you pages printed, you’ll have to start cutting them out.

NOTE: If you use card stock, disregard the use of cardboard. If you used plain printer paper (like me) it is a good idea to use the cardboard, as the plain paper is quite flimsy and may not hold its shape.

This process will take a lot of time, and can be messy, so keep a bin or rubbish bag nearby and have some space available. Make sure you keep your overlapped pieces together, and use the glue stick or glue them in place.

When you have the pieces all laid out, glue them to the cardboard, and start cutting again.

At this point, you’ll have to start folding the lines to get your shapes.

The dash lines -- -- -- -- are Mountain folds: i.e, fold the paper down so the dots forms a point, like an A with the dashes on the outside.

The dot / dash lines -- - -- - -- - -- are Valley folds: i.e. fold the paper up so it forms a v shape with dashes on this inside

Now the fun part!
Add all the pieces together, by connecting the pieces with the tabs and Edge IDs (edge 32 to edge 32, 58 to 58, etc etc).

You’ll need some masking tape for this step to hold them together, as regular glue will not stick the tabs because of the cardboard weight.

When doing this step, I recommend having your model open on Pepakur Viewer, so you can track the pieces and where the go. I recommend doing the stalk and lid together, the face, and than the back of the head, so you have three big main pieces before adding them together.

Avoid adding the bottom of the model on, as this will act as a head hole in the mask. Depening on your head size and the mask, you may have to cut some exra width into the hole to fit

Also, you can removed the back piece of the mouth as a way to see. This will be replaced with mesh (described later).

As seen in the images, I did not end up doing this step until after the paper mache, and did not work very well as it damaged the model. So it would be best to do it now, rather than later. With this, you’ll have a good visibility, but may not see much on the back sides or behind you.

When constructing the mouth, I had to place a stubby holder in the mouth to keep its shape. It is recommended to do the nose piece and the eyes of the face first, and constructing the rest of the pieces around them. I did this the opposite way, and placing the nose pieces inside the hole of the face was rather difficult, haha.

Once everything is all stuck together, make sure it all fits and looks how you want it. add extra tape to areas that need the support, and any other support (like the stubby holder) if it needs it. So by now, the model should look like a proper pumpkin. Yay! You’ve reached the stage you can start calling it a mask!

I ended up taping the whole model for support, as because I’d used clear tape, and obviously paper mache will not stick as well. Note: if you’re doing this in a hot / humid region, you may want to paper mache right away. I left it for a few days, and well... look at the final picture!

Step 4: The Process: Adjustments

So here, you’ll to do some minor adjustments.

If you want make the lid separate, so you’ll need to remove the lid of the pumpkin from the base and smooth the edges. You might do this if you want to say, place a bowel in the top so you can lift the lid and show off some candy, or whatever effect you want.

Because the mouth didn’t hold its shape well, we ended up modelling a coat hanger to fit the shape of the mouth to keep it solid. If your mask doesn’t require any adjustments, ignore this step.

Give it a quick test fit to make sure it fits well enough. If the head moves around too much, add in a quick “stabilizer” into the mask. This can be done by simply measuring out a helmet like shape and add in into the top of the mask. This will help keep the mask straight, turn when you move your head, and avoid it slipping around too much on your shoulders.

I added some Styrofoam beads into the bottom of the mask with some hot glue to keep some shape in the jaw, to help keep some shape and solidity. I did this after the paper Mache process, but I recommend you do it before.

In these images, you can see the head stabilizer and the coat hanger adjustments.

Step 5: The Process: Paper Mache

Now, you’ll have to paper mache the mask. This can be done with whatever paper mache technique you like. I used wood glue and strips of toilet paper for my mache, as that was what was convenient. However, this is up to you.

The purpose of this is to make the model stronger, and to give it more support. Because the materials are all light weight, the mask will not be too heavy to wear, but it is rather bulky.

Use as many layers of paper mache you like, keeping the features of the pumpkin. You may ‘sculpt’ the mask more to removed the blocky features. Because I was at this stage a day or two before the party, I only ended up doing one or two layers with minimal molding.

Step 6: The Process: Adding Mesh and Lights

Grab your mesh (I used a wearable fly net that we have everywhere where I live)

If you don’t want lights, you can ignore them, but if you do, continue on. Unfortuantely, I had a friend do the wiring for me (he kind of took control of it, haha). However, if you follow Noahw’s LEDs for Beginners inscrutable, he’ll explain how to wire them properly.

We placed the LEDS in the eye sockets, right in the most concave point. This will act as a “follow me” eye, and light up the eye socket when it’s turned on. The wires were stuck on the inside of the mask, out of the way, and the battery pack connected on the side, where I can reach up from the neck hole to switch on before I put the mask on. Extra LEDs were place in the back of the mask to light through the mouth, but they didn’t work as well as first thought.

(I forgot to take photos of this, but you can see the lights working in later pictures)

The mesh was stretched across the back of the mouth and hot glued in place. This will act as a barrier from people seeing inside the mask, but close enough to you for you to see out of.

Step 7: The Process: Painting!

Paint the mask however you like. I tried to stick to a basic colour scheme due to time restraints. If I had more time I would have painted much better detailing into the mask. I plan to do this on a later date.

You can use whatever paints you like, it just depends on personal preference. I used some paints that were lying about, and plan on repainting the mask with an airbrush when I have the time.

Step 8: The Final Product

Because my character, Samhein, was a Pumpkin Lord, he wore a suit. So I ended up buying a suit jacket, red tie, suspenders and some gloves to suit.

However, you can add whatever you like to your costume!

As you can see, the lights work well in the dark, and I actually spooked a few people with them, because the “followed them around”. This was particularly amusing because the party had alcohol, and those that had drunk a bit too much were utterly astounded by the costume.

Also, my face wasn’t visible to anyone, so quite a few of my friends didn’t even recognize me unless the mask was off. While it is possible to drink through the mesh with a straw, I do recommend taking the mask off to eat or drink.

BE AWARE: you can’t see behind you, or too far behind the sides, so you may want someone with you to help guide you around, and warn you if anything is behind you. However, visibility was great, even at night.