I have a part I’ve covered in aluminium tape, filleted using clay and the flange is also aluminium.
Just checking because I haven’t used clay before, I don’t know if the moisture in it will be an issue. And I recall the adhesive in the ali tape has reacted with a gel coat on me before.
You need a release coat for Aluminum, it wont release by itself. What type of release is up to you. Semi-perm, Wax, PVA, etc…
your clay has to be sulfur free. if there is any sulfur in the clay ve, poly, epoxy urathane and silicones will not cure,soft gummy mess…its not “oilfree” or"oily" clay that you need. its sulfurfree!