Is this corrosion?

[Mcstealth]

Hey folks. 

Here is a picture of some spots on the outside of the Darter that I rent. Is it corrosion? The location is about left rudder pedal distance from the spinner, but lower and behind the firewall. I will need to remove the floor and what appears to be some glue-on insulation to get to the exact location from the inside the cabin. David at Dugosh, who's mechanic is performing the 100hr, brought our attention to the area in question. I will attempt to have more pictures and info soon. 

On a funny/sad note along with the previously posted motor mount crack and two weak cylinders, we've discovered a five year old 100%  NAPA aviation battery under the cowl. Sure does work well I am here to attest. Hope its replacement works just as well.

thanks in advance. 

David

[Niko182]

Those look like rivets, where the paint is starting to come out.

[Fly Boomer]

9 hours ago, Mcstealth said:

I will attempt to have more pictures and info soon. 

I'm anxious to hear the answer to this.  Are the tiny dark spots in the center of the blemishes actually holes through the aluminum?

[N201MKTurbo]

What is inside right there? It looks like a bad repair using blind rivets with filler over them. They sanded all the plating off the rivets and they rusted and caused the bondo to fall off.

[GeeBee]

Looks like maybe somebody used steel shanked pull rivets.

 

[carusoam]

That’s some pretty wavy sheet metal in that area?
 

Something is causing paint to bubble in a few locations….

Surface corrosion can cause this as well…

taking care of surface corrosion can be quick and easy….

Better to get to it sooner than later… it has a tendency to spread… quickly.

it’s possible that the repair broke the paint seal, and is where the corrosion probably started…

 

Are you familiar with Alclad’s thin surface layer for anti-corrosion?

Great ownership style lesson coming for the Dart Flyer…. 

Best regards,

-a-

[RH Galyen]

23 hours ago, Fly Boomer said:

I'm anxious to hear the answer to this.  Are the tiny dark spots in the center of the blemishes actually holes through the aluminum?

They appear to be corrosion holes, and it looks there are more. I worked on one many years ago, it was a massive piece of corrosion. While you have it opened up, check the wing attach brackets.

 

[KB4]

Looks like someone painted over corrosion, can see bubbles forming all over.