I know there’s some other tutorials floating around but I’ve gotten asks about this so decided to type a full response here! Hope this answers some questions and can maybe aid you a bit! I’m not the best at props but I put a lot of work into these! :)
First I bought 1/8” thickness Dark Gray transparent plexiglass from www.delviesplastics.com
I vectored a pattern for the glasses shape on illustrator and printed out a size that I thought fit well to my face. Tumblr user dersedreamer has a template posted here that is really useful if you don’t want to vector your own!
I traced my pattern onto the paper that covers the plexiglass. Then I used a jigsaw power cutter to cut out the glasses along the outline I made. I’ve seen people use lazer cutting as another method which if you have access to yields awesome results! After I cut mine out I power sanded/hand sanded the edges to get them smooth.
For the arms I cut off arms from a cheap pair of glasses. Using a wirecutter I cut the metal arm right before the lenses so that there was a little bit of flat metal before the part of the arm that bends with the screw. I dremeled a small indent in the back of the glasses the size of the flat metal extension making sure to not cut in too deep so that it won’t cut a hole through the glass. Then I put epoxy into the indent and slid in the arm, it should fit nice and snug! I suggest clamping the arm in place overnight to secure the epoxy. I attached my arms this way so you wouldn’t see them attached from the front!
Here’s a pic I tried taking of the arm attachment in the back:
As a finishing touch to your shades, I’ve also been recommended by friends to heat the center of the glasses with a heat gun and bend slightly so they fit to your face a bit more. I haven’t actually done these to my pair yet because I sort of like the flat sleek look but I’m planning on doing this to a second pair I’m working on because it looks pretty awesome as well! You can see Zippyc’s glasses using this method here!(who told me about this idea!)
Here’s my finished product: (you can also check my cosplay tag!)
Good luck crafting!