I am planning the construction of a large scale dodecahedron infinity mirror, and so far the largest cost by far are the glass (or similar clear, hard material) pentagons. Each panel would be screwed on to 3D printed frame parts, amounting to 6ft tilted on a vertex. Each pentagon would be 24 inches per side, the diagonal being 38.83 inches. Therefore at least a 40 X 40" clear sheet of 3mm width would be necessary to score the pentagons.

My question is, is there any material that could be economical? I was quoted each piece at around $150 (acrylic), so very pricey for 12 of them to make up the dodecahedron. I considered stretching flexible plastic sheets or mirror film alone, but that would inevitably be subject to wear and tear as well as a warped surface (i.e. funhouse mirror rather than flat and accurate).

Hope this could be answered. Much thanks in advance.

For reference to the project, it would be similar to this: https://www.youtube.com/watch?v=WDK5xYHuQf0

  • $\begingroup$ Economical? Based on what? Bill Gates wallet? Or 19 year old on job seekers allowance? $\endgroup$
    – Solar Mike
    Commented Sep 15, 2021 at 20:55
  • $\begingroup$ Economical as in the concept of a number being lower than $150 per piece. $\endgroup$
    – lakerice
    Commented Sep 15, 2021 at 22:04
  • $\begingroup$ internet search indicates the panels cosing around $60 each $\endgroup$
    – jsotola
    Commented Sep 15, 2021 at 22:31
  • $\begingroup$ use multiple pieces per if you can tolerate the defect. There are some sizes that are economical... check furniture stuff like ikea mirrors $\endgroup$
    – Abel
    Commented Sep 18, 2021 at 2:00
  • $\begingroup$ @Abel yeah I did think about putting smaller pieces together, although I don't think it would look very good. Ikea may actually be a good idea though. Unfortunately it wouldn't work with just a regular mirror, as it needs to be a one way mirror you can see through. $\endgroup$
    – lakerice
    Commented Sep 20, 2021 at 1:14

1 Answer 1


If you have the ability to cut glass in the manner required, thereby saving those costs, you can find rear projection televisions that are being tossed out. I have ceased looking for them, as I have three collections of parts. Typically, I discovered them while driving to and from various clients in my area, but also via the now-extinct freecycle and non-extinct Craigslist-free posts.

One specific part of value to your project is relatively thin (for a mirror) front silvered glass used to reflect the television images (RGB) to the projection screen.

You'd have to be immensely successful in ferreting out enough discarded televisions for the panels you require, as you may get only one pentagon per mirror.

  • $\begingroup$ This is an interesting idea! If I can find a way to find surplus rear projection TVs that would likely work well. Only problem would be cutting the glass, which I have to admit I'm a little hesitant to try. $\endgroup$
    – lakerice
    Commented Sep 15, 2021 at 22:06
  • 2
    $\begingroup$ You'd be surprised how easy it is to cut glass correctly. Clean glass, clean cutter, lubricating fluid, steady moderately heavy pressure on a very flat surface, one pass only, hence the heavy pressure. Lift the cut, stick a ruler under it and press on the free side. $\endgroup$
    – fred_dot_u
    Commented Sep 15, 2021 at 23:17

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