My corrosion test
Posted: Thu May 24, 2007 1:57 pm
At lunch today, I snapped a few pics of the "test cell" I have set up in my back yard. It's perfect for capturing as much water as possible by sitting on my brick chimney and stacked bricks surrounding it.
Here's the environment which it sits to the west where it takes the full brunt of afternoon sun, and western arrival of thunderstorms.
This shot shows that these have been sitting outside since February 1st, 2006.
Here you can see where the water soaking brick was sitting against the Alclad. Severe discoloration, but no pitting. It has not protruded thru the Alclad layer. This does not wipe off, so it is corroding.
This shot shows the other piece, but I sprayed Napa 7220 on the lower portions and set a brick on it. It is discolored where bare alclad is, but there is not even a hint of corrosion where it is sprayed.
My experiment will conclude after I am done with the RV and flying. At that point, I'll MEK the primer and see what it looks like underneath. This is just over one year of exposure, but so far the primer is holding up very well.
Obviously, we don't place bricks on our airplanes, so this is happening much quicker than it would in reality. I will also drill the rivets out, and check the mating surfaces. Some are treated with 7220 or zinc chromate, and others are bare. We'll see...
Here's the environment which it sits to the west where it takes the full brunt of afternoon sun, and western arrival of thunderstorms.
This shot shows that these have been sitting outside since February 1st, 2006.
Here you can see where the water soaking brick was sitting against the Alclad. Severe discoloration, but no pitting. It has not protruded thru the Alclad layer. This does not wipe off, so it is corroding.
This shot shows the other piece, but I sprayed Napa 7220 on the lower portions and set a brick on it. It is discolored where bare alclad is, but there is not even a hint of corrosion where it is sprayed.
My experiment will conclude after I am done with the RV and flying. At that point, I'll MEK the primer and see what it looks like underneath. This is just over one year of exposure, but so far the primer is holding up very well.
Obviously, we don't place bricks on our airplanes, so this is happening much quicker than it would in reality. I will also drill the rivets out, and check the mating surfaces. Some are treated with 7220 or zinc chromate, and others are bare. We'll see...
