I foil with a foil H9 since may 2019 and I am really happy with it: easy to ride, stable, tolerant, smooth. I love foiling.
But I have a problem in the top part of the foil. The insert, to fix screws between board and foil, creates corrosion in aluminium all round.
This insert is in copper (it seems) and the top part of foil is in aluminium. There is electrlotic couple and the corrision spread at the inteface of both. It is not good for the durability of the foil.
Furthermore I not able to remove this insert to envelop it with Tef Gel. Thanks for your feedback to manage this problem. Henri