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Basics of Armor Construction

As I've said before, the materials I prefer to use for most of my armor projects are craft foam and styrene. Craft foam is used as a core material that provides structure and support for the armor and styrene is used as a coating material, to give the armor a nice, smooth, paintable surface.

Craft foam sheeting comes in many gauges, but deciding what gauge to use for any particular project part can be challenging. Are there certain parts of an armor suit where a thicker foam is needed for support? Are there parts where a thinner foam would look better?

This is an important issue to contend with. (So much so that I devoted an entire chapter to it in Volume One of my book series.) Over the years, I've developed a set of internalized rules when dealing with craft foam thickness. Generally speaking, if an armor piece is large and subject to a lot of movement or wear, it should be made using a thicker gauge of craft foam (like 6mm.) If an armor piece is decorative or consists of a lot of sliding, overlapping plates, then it should be made using a thinner gauge of craft foam (like 2mm or 3mm.) The only way to really be sure if a thickness will work in a certain area is to experiment. Nothing I tell you will be nearly as useful to you as getting some craft foam pieces and putting them together to see how they look and behave. The more practice and experience you get under your belt, the better you'll be at manipulating your materials and judging which thickness of foam should be used to make which piece of armor.

When making any armor item (especially larger and more tailored items like breastplates,) you should ideally begin by cutting your pattern out of craft foam and fitting the pieces together with hotglue (thus creating a craft foam mock-up of the armor, the same way you might create a muslin mock-up of a pattern if you were making a dress or other piece of clothing.) At this stage, it's easy to add and subtract material from your craft foam mock-up, trimming away excess foam from places it doesn't belong and inserting bits of foam into places where it is needed.

Only AFTER the mock-up has been finished and the final shape of the craft foam pattern pieces been determined should the last step in the construction process take place-- the covering of the craft foam's outer surface with .020" styrene sheeting. As I've said, the styrene will give the armor a nice, durable surface that can be painted with enamel, spray or automotive paint. Simply painting the craft foam by itself will not work, since the foam will merely absorb the paint. (It is possible to seal a craft foam surface with fabric glue. Here's an off-site tutorial that shows you how to do just that, although with that method, you'd have to heat the craft foam over a stove in order to shape it. There are a lot of other steps involved as well, which is why I prefer to coat my armor with styrene..)

In the "Patterns" section of this tutorial, I made a tagboard pattern for a pair of silver shoulder pauldrons. I will now show you I used that pattern to cut out the final materials for the project.
I've decided to make the pauldrons themselves using 6mm thick craft foam. I'm using a thicker gauge for durability and for reasons that I'll explain later. 6mm foam only comes in sheets that are 9" x 12" in size. Thus, I had to hotglue two 6mm pieces of craft foam together edge to edge to make a piece large enough to cut my pattern from.

(Note: craft foam comes in many colors. If the inside of your armor piece is going to be visible in any way, you should use a neutral color foam like white or black. You can also paint the interior of your armor with acrylic paint if you want to hide the color of the craft foam.)
Once the hotglue connecting the two 6mm sheets had cooled, I laid my tagboard pattern upon them and traced around the shape with a thin-tipped marker. That done, I lifted the pattern off of the foam and cut around the shape with a sharp scissors. Once I was satisfied with how it looked, I moved onto the next step...
I rolled out my sheet of .020" styrene and placed the shape at the corner of the sheet, about 1" away from the edges. I then traced out a shape on the styrene that followed the contours of the craft foam, but was about an inch larger than it on all sides. (Why did I want a 1" border of styrene around the shape? You'll see why in a minute.)
At this point, I applied hotglue generously to the surface of the craft foam in a looping pattern that covered all of the surface area in as short a time as possible. (Hotglue cools and loses its stickiness relatively quickly. When dealing with armor pieces that are larger than this, you might have to glue the styrene to the foam in stages--gluing and pressing together the layers of one small area of the armor at a time...)
Now was the time to press the styrene coating onto the surface of the craft foam. I wanted the surface of the pauldron to curl slightly so it would sit better on the shoulders of the wearer, so I took the armor piece in my hands and rolled the styrene and craft foam slightly, holding them until the hotglue binding them together had cooled. Once I let go, the armor piece retained its slightly curled shape. (This was the reason I used 6mm craft foam for this project--a thicker gauge foam holds a curl better than a thin gauge foam when glued in this fashion. It's also the reason I cut the styrene to be an inch larger than the craft foam on all sides. Curling craft foam creates more surface area on the outside of the roll. Had I cut the craft foam and the styrene to the same exact shape, the craft foam surface would have stretched past the edges of the styrene once the curling had begun.)

It's important, when curling a piece of armor like this, that you don't curl it too far as craft foam is "sproingy." If you stretch the foam too far, it could "snap back" and make wrinkles in the surface of your styrene. If you're unsure how much "curl" you want to give an armor piece, just experiment by hotgluing scrap pieces of craft foam and styrene together and seeing how much curl you can get away with. (Note: Not every armor piece that you work on will need to be curled in this manner, but knowing how to do so effectively is a good skill to learn.)

Getting back to our Pauldron Project...

Once the hotglue had cooled completely, I took a heavy scissors and cut the excess styrene away from the pauldron piece. Now all that remained was for me to apply a raised decoration to the surface of the pauldron and to figure out a way to attach the pauldrons to the costume of the wearer.

I decided to use velcro as a means of attaching the costume and pauldrons together. Taking a 4-ply thread and a thick needle, I sewed one half of a 3" long strip of velcro to the underside of the pauldron as shown. (I pushed the needle and thread through the tough layers of foam and styrene with a needle-nosed pliers.) After the sewing was finished, I dabbed a small amount of hotglue over the threads to secure them.
As you can see, this process leaves visible stitches on the outside surface of the armor--- which is why I elected to wait until after the velcro had been attached before applying the raised surface to the pauldron. (The decoration would cover up the stitches, I reasoned, making them invisible.)
By the way, the other side of the velcro strips (which hadn't yet been attached to anything) were sewn onto the costume of the wearer, in the manner shown here in the photo. (When doing something like this, the velcro on the costume shirt should be placed at the angle and level where it will have the most amount of contact with the velcro on the shoulder armor.)

Note: I used regular clothing velcro for this project. I preferred to sew it on rather than rely on velcro with a sticky back to it, as it might not always stick and trying to sew through that type of velcro (if you have to) just gums up the needle and makes it hard to push through your material.

It's now time to move onto the next part of out tutorial: Construction: Part 2--Making a Surface Decoration