OK, more mirror choices for the ‘budget-challenged’ seeking large or multiple mirrors
Glass is NOT your only option
First surface mirror is also available in Acrylic and Styrene plastics at least. Both are specialty materials available on-line and possibly from your local glass shops or sign shops. Both are normally only available as full 4’ x 8’ (1.22m x 2.44m) sheets. Styrene is available in much thinner dimensions as it is less easily fractured, and thicknesses up to .040” (1.02mm) are rolled up and boxed so they can ship via UPS in a full sheet inexpensively. Acrylic and thicker styrene must be cut down to 32” x 48” (1/3 sheet) to ship UPS.
The Acrylic is a vacuum deposited aluminum mirror just like most glass mirrors, the Styrene is a (vinyl?) mirror laminate that is bonded to the styrene and hence has a very slight ‘micro-grain’ texture.
I purchased a full sheet of 3mm thick Acrylic FSM from a local sign shop, so I have a bit more than a half sheet of excess, it is available to whomever might want it, or specific sizes/shapes from it, at my per square inch cost & the shipping. I opted for the Acrylic as I am doing a four mirror bounce in my final build, and didn’t wish to trust compounding any distortion created by the texture of the Styrene. It is important to note that with these thinner mirrors, you must plan on bonding it to a substrate material to gain rigidity, and in the case of the rolled styrene, you are supposed to unroll it immediately upon receipt and allow it to lay flat for a few days before working with it. The guys at americanacrylics.com were kind enough to send me samples of these materials before I made my decision, and I noted that the texture of the styrene is VERY minor and will pose absolutely no problem for those needing large mirrors, but stress again that it is very thin & flexible and it may take some care to get a truly flat end result.
Also interesting for the more advanced planners, both materials are heat re-formable, and therefore could make excellent choices for anyone with the math and plastics skills to calculate domed mirrors and dramatically reduce throw distance required for their projector. I would also expect the nominal texture of the Styrene to be reduced dramatically if used for a convex mirror.
