MemphisMooney

Are you willing to offer any money back guarantee on the units working?

Thanks Matt. The plastic is riveted to the lid, so it's possible to remove if I want to re-rivet. Still thinking on that. The plastic is actually bowed out from the corrosion that was behind it so I'm guessing worse case is that I spray primer and acid paint behind it. Since there was corrosion I'm inclined to do it right and remove the plastic to fully treat the metal behind it. Pay now or pay later right?

Thanks again everyone. Any advice on stripping the old paint from the plastic? Should I just flake off what's loose and paint over the old (not my preference)? I've got some Randolph on order.

Thanks everyone for the responses! I'm guessing it is the Randolph paint based on the description on Aircraft Spruce website - it looks like an asphalt coating.

Hello everyone, I've got a 66 M20C on which we are replacing the alternator. Upon opening the battery box, I noticed severe corrosion on the box lid. All of the corrosion was behind a plastic cover that's riveted to the metal and sprayed or coated with some kind of black material. I took the top home covered it with baking soda and water and watched it fizz for a solid thirty minutes. Believe all the corrosion is now gone, but the black coating is shot which I believe protected the lid from getting corrosion between the plastic panel riveted to the aluminum. Anyone know what this black stuff is? Photos were AFTER baking soda and nylon brush treatment.