There are a lot of materials out there to choose from when designing a costume. Thermoplastics are one of them but even if you decide to work with thermoplastics, there's still a lot to choose from.
What is a thermoplastic?
Basically, it's a substance that becomes pliable on heating, hardens on cooling and allows you to repeat the process. Woo hoo!
What are some examples of thermoplastics?
Some of my favorites used in cosplay include:
Moldable Plastic (Friendly Plastic / InstaMorph)
Also keep in mind that there are new products being introduced constantly. For example you can now get Black Worbla which is a bit smoother and a better product for cosplay work. For a detailed description/comparison of these a few other thermoplastic products check out Kamui Cosplay.
Which thermoplastic should I use?
Well, that's going to depend on a couple things:
What are you trying to do?
What is your budget?
Each thermoplastic has different pros/cons. If there was one clear winner, then you wouldn't have so many people who use so many different materials. But the first question you really need to ask yourself, what are you trying to do and what is your budget?
Thermoplastics vs. EVA foam
EVA foam is a go to cosplay material. It's inexpensive, easy to work with, light, and great for large costumes. The downside of EVA foam is that it's foam and can be damaged. If you want to make something that has a quality feel and is going to easily stand the test of time then thermoplastics are probably going to be a better option. Down side...you pay for the higher quality.
Okay so you've decided that thermoplastic is the right material for you, but we're back to the question, which one?
Well again, what are you trying to do? Because each material has it's pros and cons. Depending on what you're trying to do, one material will be better than another.
Most thermoplastics cannot do full circles. So if you need this then the answer is easy. You need to use Worbla or Friendly Plastic.
Worbla is very thin (1mm) and often requires using a "sandwich" method to build it up and make it thicker using craft foam. Sintra however comes in various thicknesses (1mm - 13mm).
If you're wanting a plastic that you can sculpt or mold, then Worbla or Friendly Plastic are a great option. The downside of Worbla is that it's still going to be textured so you will have to do finishing work if you're wanting a smooth surface. Friendly Plastic is very smooth and doesn't require any finishing work.
Some materials stick to themselves making it very easy to build on. Worbla sticks to itself while Sintra does not.
Different thermoplastics have different textures or finishes which may require additional work if you are looking for a smooth surface. This is where Worbla isn't great. It has a texture that require a good bit of finishing work to cover. Sintra however is smooth on both sides and requires ZERO finishing work.