Update:
Well its been a while since I've posted, and I wanted to update this thread.
So first a quiz. Can you identify the plant in the photo below?
If you answered Cornus Canadensis, your wrong. The correct answer is: it's a FWC part I was hoping to grow another FWC camper from.
All joking aside. This is the piece of latch I had left in my garden to be exposed to the elements for 1 1/2 years. Again, I live near Vancouver Canada - so lots of moisture.
Alongside it was a piece of aluminum siding, attached to a piece of aluminum trim, attached to a piece of aluminum frame. They were held together by different types of screws to see how the screws would fair, and to see if galvanic corrosion would occur with the stainless steel screws.
Pieces out of garden.
Meanwhile I left similar parts in a container of salt solution. This magnified the corrosion aspect greatly. The pieces sat in a covered plastic container. They were held out of the solution by pieces of plastic. The solution was poured over the pieces 5 times during the 1 1/2 years.
I will wash off the pieces with a paintbrush and soapy water tomorrow then take some final pictures before throwing everything away. Based on the experiment it is clear to me how the different screws preformed.