Hmmm, looks like someone didn't use the little plastic sleeves that you should. They have a counter sunk shape for the head
of the screw and a sleeve for the rib
of the screw and thus insulate the contact of both materials. Even anodised alloy will corrode given enough time when in direct contact with the SST screw. Anodising is actually corrosion
. When the alloy is anodised, it sets up a layer of corrosion on the surface. Depending on how long the piece is anodised for, determins the depth
of that layer. The layer should be deeper than you can scratch. Well theoreticaly. The colour is just on the very surface of that layer.
I have done a lot of anodising and if anyone is interested in doing any themselves, I am happy top post here with how to. It is actually quite easy and fun.
The deck is Ferro
, so I have a hole different set of problems attaching the track. Not to mention trying to get to the deck down inside the boat. It's all very pretty timber work below, but no one ever thought about gaining access to the hull
structure afterwards, when they built it all in. I intend using that bedding adhesive sealant
and I may have to use those construction screws, that have the wing thing on the nut. You drill a hole big enough for the wing to push through and it springs open trapping the nut. Tighten the screw home and bingo. But I will have to see if I can get them in SST.