Unidentified corrosion

[awatson1000]

Hi! We have a 2020 Palomino BackPack Edition HS-2910 that we bought very gently used last year. We started noticing these corrosion spots under the section that hangs over the cab of the truck (where the bed is). The previous owner kept it in an airplane hangar, we keep it in the driveway. Any idea what this could be? It started with only two spots and is now growing. Can't figure it out as it is coming from the inside out but there is no water leaks or anything we can see. Thanks!

[MR.M]

Originally Posted by awatson1000

Hi! We have a 2020 Palomino BackPack Edition HS-2910 that we bought very gently used last year. We started noticing these corrosion spots under the section that hangs over the cab of the truck (where the bed is). The previous owner kept it in an airplane hangar, we keep it in the driveway. Any idea what this could be? It started with only two spots and is now growing. Can't figure it out as it is coming from the inside out but there is no water leaks or anything we can see. Thanks!

I have seen this before . I do not think it's a water intrusion issue but an adhesive issue , is the material under there powdery? Not sure the cause or solution . I had this on one of my slides same look never could figure out what caused it . i ended up filling with auto body filler and painting . kept it small and just addressed the bubbled areas . seems to have worked but still in the dark as to the why it happened

[awatson1000]

I agree, not water intrusion. It is powdery in the spots that have opened up. It's some kind of corrosion/chemical reaction that is occurring. Just sucks with it being such a new unit. We will have to figure out a way to repair it.

Thanks for your input!

[dward51]

Is that some sort of vinyl sheet over a substrate? That's what it looks like. If so, you might be able to pull the thin sheet off along with the trim and replace it with something more durable like a cut and painted FRP panel epoxied to the substrate. That would likely stop the powering as well. If you find the powdering is extensive, then replace with some pressure treated plywood. Then reinstall and reseal trim.

[Reverse_snowbird]

Have you checked for powder post beetles or other wood eating insects?
Could a caustic liquid have been splashed on it? It looks a bit like the bubbling that occurs when someone leaves a glass of liquid on a laminated table too long and it penetrates the laminate and causes bubbling.
You're storing it outside. Does the sun hit that area with enough heat that it could be causing the glue to fail?

Welcome to the forum.

[MR.M]

Originally Posted by dward51

Is that some sort of vinyl sheet over a substrate? That's what it looks like. If so, you might be able to pull the thin sheet off along with the trim and replace it with something more durable like a cut and painted FRP panel epoxied to the substrate. That would likely stop the powering as well. If you find the powdering is extensive, then replace with some pressure treated plywood. Then reinstall and reseal trim.

it's paper thin aluminum . and the material underneath seems more like Styrofoam rather then wood / at least that's how it was on my slide out side wall . looks the same as op's