So with this instructable I am going to start out with things I wish I had known ahead of time before starting the helmet.
The more hands, the better. I was using elastic bands, tape and heavey objects to temporarily hold things in place until I could secure them properly, if I had an extra set of hands to hold these things life would have been so much easier. So tip one, it's so much easier if you have someone around to help construct your cardboard base.
Nothing is a bigger pain (to me at least) than not being able to work on your project because of drying time! It's awful for an impatient person like me. If I had started my helmet and shield at the same time I could have been working on one when the other was drying. Tip two, if you're making more than one prop, might as well do them all at the same time.
A helmet too big is way easier to fix than one that is too small. If the helmet is too big you can add styrofoam or more cardboard inside to tighten it up. A helmet that is too small is a bigger problem, you'd need to start pretty much from scratch again. Tip three, when in doubt make it a bit bigger.
Now we can get started! I hope I can explain this process easy enough, it was a lot of trial and error. I googled a picture of a Spartan helmet so I could see some of the basic shapes. I started out by making the front of the mask. Take a sheet of cardboard and draw so the corrigation is going vertically, it will come in handy later on. I made it in two halves because there is a strong crease down the front and I think it could only be achieved by attaching the two halves. I drew the basic shape of the mask, and held it up to my face to match proportions and also used a ruler to measure. I cut out my shape and held it again to my face, marking with a pencil which parts needed to be tweeked. I used a boxcutter and trimmed off anything extra I needed to then traced the shape and cut out the mirror image. Tape the two halves of your mask on what ever side you choose to be the reverse side.
This is where the direction of the corrigation comes in handy. Make little bends all along the corrigation, this will easily and evenly give the front a rounded effect. Hopefully you can see it in the picture.
I then put the mask to my face and used a pencil to mark where the top of my head met the mask and on each side. I took thin strips of cardboard and used them as a guide to build the "hat" part of the helmet. I didn't bother attaching them too well because I removed them once I had started taping on the solid pieces.
I used paper to trace the shape that my thin cardboard guide lines created and then cut them out of cardboard. I grently bent the cardboard and rounded it a bit, taped the two pieces together then attached it to the mask. Your helmet should now be able to sit on your head, I just taped on a thicker strip of cardboard to make the head piece come down and cover the back of my head a bit more. Now you can pull out your thin strip guidelines, they are no use to you anymore. Use lots of tape and make sure every joint is secure, the last thing you need is pieces comming away when you are on your paper mache stage.
Leonidus has (for lack of a better word) a mohawk on the back of his helmet, we are going to make a little trench for it to sit in. I layered up three strips of cardboard and taped them together. I then measured it to fit the back of the helmet and cut off any legnth that overhung. I then traced a guideline about 1cm onto my strips so i could cut away the inside evenly, you should end up with what looks like a long and thin frame. Tape the frame to the back of your helmet. The building of the base is done! It's a long tedious process but so worth it.
Used your white glue and paper towel and paper mache the entire thing, inside and out. I did two layers on the outisde and one on the inside to avoid making the inside too snug on your head.
Let everything dry well and paint it gold. Use the same technique as the shield, paint on some diluted brown or black paint then wipe it off with paper towel. The dark paint sticks in the crack and creases and created a dull and worn look.
The final steps, the mohawk! I used two broom heads I bought at the dollarstore and cut the bristles off. We need the bristles to be on something flexible so they can lay flat and follow the shape of our helmet. I glued the bristles onto a strip of dark fabric, that was with legnth and width of our trench. I used a hot glue gun for fast drying, we don't want to stand around all day holding on waiting for it to dry. Glue your mohawk into the well and you're done!
I`ll be posting some more picutres of the final product and with the costume all together asap.
I also made a Spartan shield to go with this helmet.