I see no issues, have done it in fact
We used archival hot tissue that you can then reheat and take the print off the aluminum
this is how registration work is done.
It seems everybody using FB has it's own recipe to make it flat. I am fixing the paper with clamps between wooden frames and glass.
With this method the paper becomes very flat after drying - I'm quite pleased with the result. The only drawback is that I need to cut the borders because the pattern of the frame remains printed on the paper surface.
I'm thinking whether it would make sense to mount the paper BEFORE exposure/processing?
I could use 3M photo to mount the FB on 2-3mm thick sheets of aluminium.
What do you think of this idea? Could there be problems during developement due to reactions with the metal / during washing due to the impermeable back? Could the durability/stability of the image suffer?