My main local source of all things photographic, Fotoimport.no, has this to say about aluminium mounting:
Roughly translated and abbreviated: "1.5mm aluminium plates are sized with a mixture of 30% glue and water. The glue, Lascaux Akrylkleber 498HV, is used for artist's collages. Allow to dry, then apply a layer of glue. The wet or rewet print is then wiped of all surface water, smoothed onto the plate, and the whole allowed to dry overnight. As soon as the surface is dry some heat treatment will increase the strenght of the bond.
The print will be bonded permanently to the sheet, and cannot be removed without very strong solvents. It can be washed, bleached toned, redeveloped or whatever without coming off."
That answer the question?