acrylic or PETG?

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#1 Midnight Dawn on 9 months ago

I'm currently working on a mask I've been thinking about building for about a year now as I finally got all my ideas in order to make this work. Finalizing my thoughts on the matter this is going to be a thermoformed.

But the question I'm still on the fence about is should it be acrylic (plexiglass) or PETG?

Both have pros and cons attached to them.
-pros: high durability and the right light refraction I'm looking for.
-cons: weight might prove to be an issue. Might be a little toxic to attempt to thermoform it.

-pros: pretty light weight and very easy to thermoform without risk of toxicity.
-cons: kind of pricey and easy to break. Light refraction will most likely be off.

So I'm hoping for some opinions on this one.

#2 vonjankmon on 9 months ago

My first thoughts on this is what your options for a work space are. Acrylic requires a higher temperature to thermo form, which makes it a bit more difficult to work with, along with the out gassing issue. If you have a well ventilated work area that can support a thermo forming machine capable of reaching the correct temperature go for it. If you are going to have to use your oven to heat the plastic and then form it in a small machine on your kitchen floor, I would go with the PETG.

#3 Midnight Dawn on 9 months ago

That actually leads into another problem.

Pro: i found a facility nearby that has a thermoforming machine i can use.

Con: i only need to use it once but i need to pay for a months pass which is kind of pricey for something i'm only going to spend less then 30 minutes on.

So i'm in a bit of a jam here in trying to figure out if its all worth it.

#4 Penlowe on 9 months ago

I'd buy the pass then flip through my mental "I'll make that someday" list and do the thermoforming for as many as I could do in that month. If nothing else make a bunch of face and body molds for future whatevers.

#5 vonjankmon on 9 months ago

I would also consider the fact that you may not get it right the first time. The thickness of the material can affect your outcome significantly, so you may have to try a second time. A month long pass may be perfect if you need to re-order some material and try again.

#6 Midnight Dawn on 9 months ago

Good point.

Best to make multiple copies in the event of derivatives I want to try to construct later on.

But still that month's pass is a real stinger. Yet best to bite the bullet on this one I suppose.

#7 nathancarter on 9 months ago

[QUOTE=Penlowe;5068788]I'd buy the pass then flip through my mental "I'll make that someday" list and do the thermoforming for as many as I could do in that month. If nothing else make a bunch of face and body molds for future whatevers.[/QUOTE]

Agree with this. And, that makerspace might have many other machines you can use, such as a laser cutter.

Director's cut alternate ending: Make a tabletop vacuum former yourself, and use it as often or as rarely as you wish. I did this, and it's SO SATISFYING to vac-form things. Mine is 13x9", which is the internal dimension of the biggest toaster oven I could find on Craigslist. Total cost to me was about $40, though if you have more or less junk at home it might cost you less or more.

I have made forming bucks out of wood, plastic, floor-mat foam, and random junk; and I form a lot of stuff over random household objects - the glass dome out of a lighting fixture; kitchen mixing bowls; metal teal-light holders, little metal boxes, whatever I can find.


#8 Midnight Dawn on 9 months ago

@nathancarter - i considered this in the past. But i have two issues with building one kyslef.

First issue is space as when its not in use i have no place in my house or storage space to put it. I can easily build one as thats not a problem for me. I just have no idea where to put it when im done with in.

Second issue is the heating element. I prefer to avoid oven baking this so im going to need nichromium wire to serve as heating coils. However i have a bit of trouble getting my hands on this unless im willing to break apart a toaster, a blow dryer, orsome sort of heating device.