Eva question

[BadaxeGC]

Hello, new to the world of prop/costume making and have decided to start small with an easy costume for an upcoming event. My question is about the stiffness of EVA. The prop in mind is a boomerang. Measuring at 18mm in thickness doesnt leave me much room for a core so I was wondering what my options were without one.

My question:
How does a piece of 18mm EVA compare to 3 pieces 6mm layered in stiffness/flexibity?

I would like my boomerang to have little flex when waved/moving around.
Thank you for your time

 

[PlanetAlexander]

I've made a tachi (Japanese sword) from 2x8mm of foam, coming to 16mm. I used a metal ring (can't remember what kind of metal) and bent/cut it to shape, then used that as the core. I think you might be able to get something called armature wire?
Here is an Evil Ted video which should help:

Good luck with your prop, and I hope you enjoy the world of foamsmithing!

EDIT: Just a tip when stacking layers of foam without a core - if you curl one side as you lay it down to stick the two together, it's possible that the piece might curve overall. It's happened to me, and while heat forming it flat afterwards helps, it doesn't resolve the issue. So I'd say even when you don't think you may need some sort of core, use one!

 

[BadaxeGC]

Ill test with some armature wiring but I feel like it may not be a good stand alone core. Then again, what the hell do I know, ahah (noob).

I wouldnt be in such a dilemma if it wasnt for the boomerang's curve.

 

[PlanetAlexander]

If you're worried, then always do a test first. If something goes wrong, great! You've learnt something.
I think I used either 3mm or 5mm steel ring, bent to shape for my sword and it's held up great.

That's an image of the length of the sword with my Yoshimitsu cosplay. Not a very good cosplay, but this was all made before I learnt a whole bunch of new cosplay techniques.