Jan van Gastel wrote:

It can be glued directly to the bars. Make the silicone blobs 2-3 mm thick
and 10-12 mm. wide. For alumium you need to use a primer for better bonding
of the silicone glue (I have experimented with that). Before applying primer
or silicone, the metal has to be cleaned well, with acetone or
trychloorethyleen. If done well, there is absolutely no change the mirror
will come loose.

Thank you for the answer. What are you using for the primer?

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Lauri