Make an EVA Foam Legend of Zelda Master Sword & Scabbard

Legend of Zelda Master Sword

Halloween is approaching and it's time to start making. I'm working on a Link costume from The Legend of Zelda.
This is for a child's costume, so foam is a safer material than wood or resin.

 Materials:

• Sword and scabbard pattern, I've provided the pattern but it is scaled to a child
• EVA foam floor mats
• craft foam
• 3/8" threaded steel rod 
• 1/8" hard board to serve as a cutting guide for angles
• contact cement
• plasti-dip
• Rustoleum spray paint - blue, gold, green

Tools

• hobby knife
• metal straight edge
• ruler
• metal file
• leather punch
• electric sander
• drill and hole saw
• rotary dremel with grinding bit
• rotary dremel depth attachment
• oscillating dremel with cutting bit
• wood burning tool
• heat gun

 Master Sword

I first sketched the sword in Google Sketchup. I scaled this to a 30" length, which is in proportion to the costume wearer. An adult would need a larger sword

I then printed out the template and traced it to the foam. I cut out the full shape with a hobby knife. You'll need to cut out the sword shape twice as we'll glue the two pieces back to back.
It's okay if the cuts are a bit rough because the blade edge will be beveled later. The hobby knife should cut through the foam easily. Replace the blade often for sharp, clean cuts. I used an electric sander to smooth off the pattern on the back side of the mat.
I buy anti-fatigue mats from Harbor Freight as they have the best price.

It all starts with a sketch.

Trace the shape onto foam.

A sander removes the pattern on the back of the foam mats.

While I started with one big sword shape, I later cut the sword into individual shapes. This will produce the best accuracy. It's more difficult to carve out the entire shape and easier to carve out individual pieces.

A dremel grinding bit creates the channel for the threaded rod.

While I wanted the blade thinner, the thickness will be (2) sheets of foam so that I can embed a rod.
The foam by itself is not rigid enough. I'm inserting a 3/8" threaded steel rod cut to length. A threaded rod provides more grip than a smooth rod.
A dremel with a grinding bit and depth attachment creates a trench down the middle to embed the rod.
I left the rod 1" short of the tip and .5" short of the hilt. If you run it all the way out it could puncture the foam and injure someone.
The rod ended up being short on the hilt side. When I made individual pieces, the handle got longer as I'm restricted to (1) or (2) pieces of foam. Re-cutting a piece of foam to make it thinner is too much trouble.I should have waited to cut the steel rod until all my pieces were done.

Use scrap wood to act as a guide for bevels.

I used hardboard as a guide to get the taper of the blade edges, using a the oscillating dremel tool for the cut. I glued the blade halves together over the rod, with enough of the rod protruding to attach the handle. Coat both pieces of foam and the steel rod with the contact cement, then reapply immediately because the foam will soak in the cement.
The rotary dremel with a grinding bit smoothed out any roughness on the blade. I set the speed to 15-20k rpms depending.

For the handle I cut out pieces of foam and glued them together using contact cement. Previously with foam I've used hot glue, but decided to try contact cement. It's really nice not burning myself or having strings of glue everywhere. The bond is very strong with contact cement.

Contact cement is used to glue the foam together.

With contact cement, apply it to both surfaces, reapply, then let it dry for ten minutes. You only get one shot at placement, most of the time, so get it right.
Using a dremel and file, I shaped the handle pieces which will later be strung onto the threaded rod. Since the handle as various tapers, I cut out shapes with a hole saw. I was restricted to the hole saw sizes I had, but I got pretty close.

Foam shapes were cut out with a hole saw.

Hard wood guides sandwich the foam with a metal rod through the center.

File any rough cuts smooth.

The hilt pieces glued and shaped.

For shaping the rounded pieces, I glued up foam to an equivalent thickness. Sometimes it was a bit thicker or thinner than the reference. 
I drilled a hole in the center for the steel rod, but then ran another bolt through. I cut pieces of hardboard to act as a guide, sandwiching the foam in between with nuts on each side and clamped the rod in a vice. I then used the oscillating dremel to cut to the guides with the rotary dremel and a grinding bit to smooth out any imperfections. The guides ensure uniform angles and cuts. I then assembled the small pieces.

The handle is a craft foam wrap. I first glued just one edge to the rod, then glued a little bit at a time, wrapping it around the handle, until the thickness was accurate.

The handle is craft foam wrapped around the rod.

I used a dremel and wood burning tool to create the indentations in the hilt. Breaking the shapes down further would have made for a cleaner and more accurate final product, but this is a kid's toy and those details just aren't necessary. This approximation is close enough.

A wood burner created the cross guard details.

Craft foam for details.

I used a wood burning tool to create the triforce symbol in the blade, but did not create the filigree because I didn't think I could make it look good. Craft foam is used for some of the other details.

A nearly complete sword.

The diamond shape is more floor mats cut at an angle.

The handle grips are just thin strips of craft foam glued to the handle. I used tape as a guide to line it up.

Once everything is glued up, use a heat gun to close the pores of the foam before plasti-dip. The foam will darken slightly and acquire a sheen. This step doesn't take long, so don't burn the foam. Heating the foam closes the pores so it absorbs less paint.

I plasti-dipped the entire sword once assembled. Then I taped off to paint the various parts, using blue, green, silver, and gold. Be thorough in your taping to avoid overspray and leaks. I had a few.
You'll have to paint in sections. I'd paint one color, let it dry for 24 hours and then paint another section
If this was for me, I'd do a dark wash to make it look a little grimy and used. It just adds a nice degree of realism, but the costume wearer wanted to forgo this step.

Master Sword Scabbard

I made a scabbard in much the same way. It's all foam, sized to fit the sword. I waited until the sword was complete before building, just so I knew it would fit.

The edges were rounded over with the dremel and craft foam creates the details.

 

 

To line up the triforce shapes, I taped them together first aligned correctly and glued them to the scabbard as one unit. The craft foam details were cut long. I'd glue the face of the detail on each side, making sure to line them up, then wrap the detail around the edge. Overlap the edges and cut in the center. It's a perfect seam that can then be glued down.

The bolts/rivets are craft foam. I used a leather punch to punch the perfect circles out of the craft foam.

The leather band is real leather, contact cemented at the seam. The loops for the leather are craft foam.

Scabbard Harness
The scabbard harness is leather and craft foam. The main strap is leather cut to size. The shoulder pad is foam, though I should have made it all in yellow so that the brown shoe polish would have colored it better. I used shoe polish on the foam and leather to get a more accurate brown. I wiped it on then polished it with a t-shirt. The should strap is two pieces of foam glued just along the long edges. I added a piece of foam on the interior top piece to give it the correct thickness.

The secondary strap is leather too. I made a loop with leather that is large enough to fit the main strap. The ends were attached with contact cement. I slit one side of the loop and used contact cement to glue the secondary strap to the loop.

The button is a decorative furniture tack. I filed the sharp point down and bent it down. I put a snap on the back of the secondary strap for easier removal.

I shaped a piece of aluminum for the hook and riveted it to the leather. The holes for the rivets were made with a leather punch tool.

 

The strap was sized to the wearer. The weight of the scabbard and sword pull the entire strap back, so I had to tie it to the belt.

The leather strap on the scabbard hangs on the aluminum hook. I painted the blue first, not taping anything off. Then taped out the blue and sprayed the gold.