Those three shapes of EVA foam sticks (rods/dowels) are incredibly versatile tools in a cosplayer's arsenal.

Here’s a breakdown of each type and their most common uses:

1. Circular EVA Stick (Round Rod/Dowel)

This is the most common and versatile type of EVA foam rod.

• What it is: A solid cylinder of EVA foam.

• Primary Uses:

• Structural Support: The #1 use. They are perfect for creating internal skeletons for props like swords, staffs, scepters, and giant keys. You glue them into a channel carved into thinner foam layers, making the prop rigid and preventing it from flopping around.

• Handles: Excellent for making comfortable, lightweight handles for any weapon or tool.

• Piping/Details: Perfect for adding raised, rounded details to armor, gauntlets, or sci-fi guns. Think of things like hose lines, reinforced edges, or decorative trim.

• Axles & Rivets: Smaller diameter rods can be sliced into discs to act as rivet heads, gears, or axles for moving parts.

• Cosplay Examples:

• The handle and central core of a Keyblade (Kingdom Hearts).

• The staff of Gandalf's or Morgana's staff.

• The inner structure of a Buster Sword (Final Fantasy VII).

• Piping on Iron Man's or Master Chief's armor.

2. Semi-Circular EVA Stick (Half-Round Rod)

This shape is all about creating strong, beautiful, and consistent edges.

• What it is: A circular rod that has been cut in half lengthwise, giving it a flat back and a rounded front.

• Primary Uses:

• Reinforced Edging: This is its superpower. Gluing a semi-circular stick along the edge of a piece of armor (like a pauldron or breastplate) instantly creates a strong, rounded, and professional-looking border. It protects the fragile edge of the base foam from dings and damage.

• Decorative Molding: Used to create the look of carved or raised decorative borders on shields, armor plates, and architectural details on props.

• Seam Covering: It can be used to hide and decorate seams where two large foam pieces meet, giving it a finished, industrial look.

• Cosplay Examples:

• The rolled edges on Captain America's helmet and shoulder armor.

• The detailed trim on Wonder Woman's armor and tiara.

• The reinforced edges on any knight's pauldrons or couters (shoulder and elbow armor).

• The borders on a Hylian Shield (Legend of Zelda).

3. Triangular EVA Stick (Triangle Rod)

This is a more specialized shape used for creating very specific, sharp aesthetic details.

• What it is: A rod with a triangular cross-section.

• Primary Uses:

• Greebles and Tech Details: Essential for sci-fi and tech-based cosplays. Gluing small pieces of triangular rod onto surfaces creates instant panels, vents, and intricate mechanical-looking details ("greeblies").

• Arrowheads & Spearheads: The natural shape makes it perfect for crafting the base of fantasy arrowheads or spearheads before adding details.

• Crisp, Angular Edges: While not as protective as the semi-circle, it can be used to create a very sharp, faceted look on armor edges, especially for evil, robotic, or crystalline characters.

• Decorative Inlays: Can be used in patterns to create channels or segmented designs.

• Cosplay Examples:

• The angular tech details on Genji's armor (Overwatch).

• The sharp, faceted armor of Dark Star characters (League of Legends) or Necrons (Warhammer 40k).

• The crystal shards on a Dark Crystal or Steven Universe cosplay.

• Details on weapons from Destiny or Mass Effect.

How to Work With Them:

• Cutting: Use a very sharp hobby knife or a utility knife. Roll the rod as you cut for a cleaner slice. A bandsaw is ideal for thicker rods.

• Shaping: You can easily sand them with a dremel or sandpaper to blend seams or alter the shape slightly.

• Gluing: Use contact cement or super glue (CA glue) for a strong, permanent bond. The flat back of the semi-circular stick makes it especially easy to attach.

• Heat Forming: Like all EVA foam, you can use a heat gun to gently warm them and bend them into gentle curves. Be careful not to overheat and melt them.

Summary Table:

In short, you use circular rods for the bones, semi-circular rods for the skin and edges, and triangular rods for the sharp, techy details. Having all three in your toolkit will massively level up your cosplay prop and armor builds.