We are trying to attend to some aspects of Riki Tiki Tavi that need attention from time to time. One of the issues we face is galvanic corrosion.
When two dissimilar metals are in contact with each other, there is a tendency for electrons to move from one to the other. In this case salt water is the electrolyte, the aluminum Lewmar block housing is the anode, and the stainless steel support is the cathode. The remedy is to separate the metals thereby not allowing them to touch each other, stopping the flow of electrons and hence the corrosion. Originally this was done with a piece of rubber mat, but over time this began to fail and have small holes, and then let the electrons flow… We found a replacement in our recycling bin.
It looked like this:
So first I took it apart. Here you can see all the nuts and bolts and also the rubber mat that needs to be replaced. The white powder is corroded aluminum.
I then cleaned the stainless steel support as well as the hardware and aluminum piece.
Then came selecting a suitable new separator…. we had an old yogurt container on hand, as well as an empty milk jug. Good enough.
Next we had to trace where the bolt holes would need to be as well as how large the entire piece needed to be to ensure no touching of stainless with aluminum.
To punch the holes, I used a single hole punch like you’d use for paper.
After everything was clean and dry, I liberally applied some Lanocote which helps protect and neutralize corrosion products, should there be some corrosion developing in the future (always seems to be happening).
A little trimming and then done 🙂