Re: Slumping mirrors.

I'd like a 'silvered' layer in the middle, for protection, and was referring to the stainless/aluminium as an alternative.

Mirroring after slumping is awkward, as I'd like it to survive 10-20 years outside without getting pinholes even when rained on.

It's for a decorative photovolataic collector.

Thanks for the comments.

Another option is chrome-plated steel (or copper, bronze, etc., or perhaps even plastic or glass). If done well with a heavy plating, that would keep its mirror finish with less maintenance than aluminum (and maybe less than stainless as well). But chrome plating is not a do-it-yourself operation, if that's a concern.

Or how about applying a good automotive finish to the back of your slumped mirrored-on-one-side glass (assuming that the slumping process doesn't degrade or destroy the mirror coating)? You would probably need to seal the edges somehow, unless you used a clear coat and covered the whole mirror (front, back, and edges).

Are you talking about a simple 2-D curve (like a trough) or a compound curve (like a paraboloid)? If the latter, will it have drain holes, or is it going to be positioned or sheltered such that it doesn't collect water? Otherwise your photovoltaic collector may turn into a shiny birdbath if it's in a region that gets much rain!

Bert

I suspect it's likely that unless it's done in an inert/hydrogen atmosphere, a normal silvered mirror can't be slumped.

I wonder if it would work, if it's done in a reducing furnace.

Anyway, it could be silvered later.

Compound curve, and it will not collect water, due to the design.

Slumping in an inert/hydrogen atmosphere? Sounds interesting. I'd go heavy on the inert and light on the hydrogen.

Well, it depends if you like bangs or not :) On the plus side, you could probably just sprinkle silver oxide on the surface of the glass, put it in the furnace, and out comes a mirror.