|Mylar glued to aluminium using contact adhesive -|
Very Very Wrinkly!! (but still reflective)
The Mylar is not mirror finish, but it is very bright, like very clean Bacofoil, and being plastic, it doesn't crumple like Bacofoil. It is double sided, and very slightly transparent.
|Mylar, highly reflective, but inexpensive|
My idea was to tape it on with exterior quality duct tape, but we thought I could experiment with contact adhesive, using the mirror that is over the kitchen window.
Here is the first result, using adhesive. It looked fine when I first did it, but after 18 hours, the surface has resolved into a complex pattern of wrinkles. The mylar has glued well, but any air trapped could not escape, and small air bubbles grouped together. It is very brightly reflective, but energy is scattered, and I don't know how it will weather. A smoother finish is required.
|The aluminium reflectors look bright in this|
photo, but it is relative - they are very
tarnished. Mylar would change them
Fastening to upper mirrors
If I had an 'industrial' method such as a power roller, I could roll out the small wrinkles, if working on a flat bench with sprayed contact adhesive. The mirrors on the Sunbox are not detachable easily (without a scaffold) and for quick attachment without adhesive, at high altitude, the tape seems to be the only method. I don't go up the ladder very often, but get slight herby-jeebies every time, wondering if it is my last time!
Taping would be more easy to stretch to get a more optical finish and smoothness, and it would be replaceable every few years, as tape can be replaced and Mylar is very cheap. The carriage cost as much as the roll!
The interior mirrors also need some Mylar, and as these are not exposed to wind or weather, they would probably be easy to tape, and very long lasting. At the moment, there is some aluminium sheeting in there.