I am creating a sword for cosplay, and I need the material used to be clear, rigid, and lightweight, and to cure properly in such a thin mould (and can be poured into the mould I have, as I'd prefer to not start an entirely new process, although I'm open to any suggestions).

I have a mould made from a platinum-cure silicone rubber. It's a pretty simple shape with a 3mm thickness.

left, the blade will be made by connecting multiple together. The center: I'm pointing at where ill put the led strip, facing outwards to light up the plastic. right: the mould used
To the left, the blade will be made by connecting multiple together. The center: I'm pointing at where I'll put the LED strip, facing outwards to light up the plastic. To the right: the mould used

I have attempted to use a fast cast urethane resin, with a shore D hardness 72 that is clear.

The material I used is mass sensitive (cures better at a greater volume/thickness), and does not get very rigid since the mould is quite thin.

Are there any other types of plastics I could use that meet my needs?
I can include pictures of the shape I've tried to cast if that would help, or links to the products I've used so far.

  • 1
    Those would probably be useful (pictures and links); something else that would probably be useful would be to know what you intend to use it for.
    – walrus
    Aug 29, 2018 at 8:25
  • 2
    Have you tried clear resin? It's clear, transparent, rigid and easily mold-able. I personally use hot glue for smaller items, as it is easy to work with, but I don't know if it'll be a good choice for something as big as a sword.
    – Bella Swan
    Jul 3, 2019 at 6:30
  • 4
    This is a year-old question, so probably overtaken by events. But if the need arises again, I wouldn't try to cast something like this. Even a metal sword is a lot thicker than 3 mm. Plastic that thin will either be very flimsy and flexible, or brittle and easily broken. I would cut the blade from a sheet of something like clear Lexan. Judge the required thickness by how flexible the sheet is. If you're just going to wear it, it can be more flexible than if you intend to wave it around.
    – fixer1234
    Aug 25, 2019 at 0:41
  • 2
    @fixer1234 Surprised I didnt find that type of plastic when I was doing my research, Thank you for the suggestion! I actually ended up using a large sheet of .. I beleive it was polyethylene. creating two individual pieces where I heat sealed the outer seam (the cutting edge of the sword). it Is very rigid (but not brittle) and the plastic alone weighted roughly 1.3 lbs at 3mm thickness I believe (might be off, was recalling details by memory) You can see the outcome here youtube.com/watch?v=90mCj-MINkg Nov 18, 2019 at 0:57
  • 2
    Very impressive job! It turned out great!
    – fixer1234
    Nov 18, 2019 at 1:25


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