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Thread: A suitable plastic for very detailed work?

  1. #1 A suitable plastic for very detailed work? 
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    Hi all, I figured a science forum would be the best place to get an answer for a question like this, since it's likely that members here know more than their fair share about plastics and whatnot.

    So, my friends and I have decided that we'd like to make some sort of gauntlet from scratch out of plastic or a similar material.

    Anyway, the toughest part of planning this out so far has been finding a suitable plastic. We pretty much need something that can be molded very easily- it'll probably be easiest to do this with a thermoplastic, but I wasn't quite sure if they are moldable enough, even when heated to their ideal working temperature. I mean, acrylic is a thermoplastic, and I can't really see that, no matter how thin and perfectly heated it is, being able to be formed into shapes as complex as a hand. And of course, cheaper is always better. If acrylic works, that's plenty cheap though, of course.

    So yeah, basically, I'd like to know how big of a can of worms we're opening with this. Thanks in advance for any and all feedback! :wink:


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  3. #2  
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    Thermoplastics will require a mold of some sort. What you are descibing is a rather complex one because of the temperature
    Youare better off using a casting resin plastic, a much simpler mold will still be required.
    look at Reynoldsam.com they have all the stuff.


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  4. #3  
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    That does sound a bit simpler, though we do have a lot of acrylic just laying around the house, and if there's any way for us to do it using that, I'd prefer it.

    You said the main issue would be temperature. Do you mean creating a temperature high enough to melt the thermoplastic, or maintaining that temperature as we work it in the mold?

    Since we're probably going to create each piece of the gauntlet (fingers, hand, forearm) separately, I didn't think it would be too hard to make a mold for small parts such as those and then heat the acrylic to a point where we could quickly place it in the mold and allow it to harden into those individual shapes. Then we could connect those individual pieces to each other somehow.

    Sorry to be persistent about trying to use the acrylic, but I'd much rather use what we already have laying around rather than having to buy new material, wait for it to come in, etc.
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  5. #4  
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    Plex has a MP 1n excess of 160 C. to mold sheet you you would have to heat apprx 10-20 degree less and then use a vacuum mold. what do you paln for mold material? Casting sound easier yet?
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  6. #5  
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    Quote Originally Posted by fizzlooney
    Plex has a MP 1n excess of 160 C. to mold sheet you you would have to heat apprx 10-20 degree less and then use a vacuum mold. what do you paln for mold material? Casting sound easier yet?
    You don't necessarily HAVE to use vacuum processes. There are many ways to thermoform plastic, including something as simple as even doing free-forming, as listed here: http://plastics.inwiki.org/Types_of_thermoforming

    And I think 150 C is a pretty comfortable value. If I use a metal mold and hook up my power supply to it, with a little voltage modification, maybe I could even heat the mold to that temperature to keep it pliable as long as I need. Though wood is probably much easier to work with. It DOES sound confusing, but it might work if we work on the thing in small increments (ex: a simple half-cylinder- like shape for each half of each finger, and then hinge them together) and then glue/epoxy that all together.
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  7. #6  
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    If half cylinders are all you need why not just slice up plastic tubing?
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  8. #7  
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    Quote Originally Posted by fizzlooney
    If half cylinders are all you need why not just slice up plastic tubing?
    Heh, well, it does seem like certain parts will still be a bit more complex than that. Ex: The palm will have to be... palm-shaped? (Duh >_<)

    But the point I was trying to make is that I don't need to make the shapes 3D from the beginning in any way, I can make two halves of it using cavity molds and attach them together. Wouldn't that make it significantly easier to work with acrylic?
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  9. #8  
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    Hot sheet acrylic is difficult to work with at best, without a vacuum mold you will get very little detail, check out the reynolds site they have videos on the casting process. Why are you so hung up on acrylic sheet?
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  10. #9  
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    Meh, it's mainly cause using other things would be more expensive. I COULD just buy Wonderflex and be done with it, but the whole point of this thread was trying to figure out a way to do it cheap. Plastics can be very expensive. I figured we could always do the detailing in aluminium anyway and just make the basic shape in acrylic. Is that more feasible?
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  11. #10  
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    An old marine buddy once told me "you can't make chicken salad out of chicken shit"
    use the right materials for the job or forget it.
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