Mirror polishing thin aluminum sheet on both sides without warping

[KamorkasOa]

Hello all,

We're trying to find a solution to achieve the same degree of standard grade mirror polishing on both sides of some rectangular pieces of 1 mm thick aluminium sheet, whilst retaining the flatness of the sheets.
The largest piece is 1500 mm x 300 mm (5 ft x 1 ft)

These will be components for an artwork we're trying to make, so lightness of material is imperative, hence aluminium.

The samples we received from the local polishers were bent from stress relieving as they were made from one-sided mill finished mirror-polished aluminium which was then shop polished on the reverse side.

Your thoughts would be appreciated - is electropolishing an option?

[ircasodle]

he obverse side of bright rolled sheet is usually deliberately roughened to give grip in the rolling process and is very difficult to smooth to a mirror finish - as you have found. Although chemical or electrolytic polishing would brighten and smooth the rough side I doubt if it would produce an adequate surface finish. It would also tend to diminish the mirror properties of the bright-rolled side. Of course, I am guessing you requirements.

If feasible, I would consider glueing two thinner bright-rolled pieces together or even glueing kitchen foil to an aluminium (or other material) substrate. Is that practicable? Also consider aluminized plastic.

I feel a little guilty in saying this as my moderately comfortable retired life-style is due in great part to a lifetime developing, promoting and supporting aluminium brightening processes!