Replacing Aluminum Gray Wrap

[Re-Pete]

Can anyone help me with some information on the guage of the plate aluminum that is used to stiffen the beds (bottoms) of the street side sections of Gray wrap that run under the electric cord locker and the section under the 3" dump spout?

I've including pictures.

The aluminum plates seem to be about 18 guage, but in my case they are laminated to inside of the gray wrap with vulkem caulk and the edges are mostly corroded.

[jerunamuck]

My 90' Excella has different material.
The flat area of the under chassis is an 18 gauge galvanized with a plastic coating on the inside. probably for electrical isolation to prevent electrolysis corrosion between it the the frame. Part of my seasonal maintenance is inspecting and replacing rivets as needed since they are corroding. Last year I tried some 3/16 HDPE rivets (left over from a canoe repair project) where the rivet hole corroded too much to allow replacing with a 1/8 rivet. Those still look good a season later so I'll probably get some more of them. The curve portions are Al like the exterior walls and there appears to be something between the All and Galv all along the seam. My guess is it's there to provide electrical isolation to cut down on corrosion. The corner bits are all custom formed HDPE. Where your sheeting behind the tires appears to be stiffened by another sheet of metal on the inside, mine had a sheet of Nylon bonded to the exterior behind the tires. I presume this is rock protection. I've had to replace those since the glue failed a few seasons ago and the Nylon sheet was flapping in the wind. I ended up replacing that ~1/16 Nylon with several much thinner sheets of HDPE laminated. Doing it this way allowed a better bond area since I could use a small roller to work the bubbles out of the epoxy for each layer. So far, no delamination.

[Re-Pete]

Originally Posted by jerunamuck

My 90' Excella has different material.
The flat area of the under chassis is an 18 gauge galvanized with a plastic coating on the inside. probably for electrical isolation to prevent electrolysis corrosion between it the the frame. Part of my seasonal maintenance is inspecting and replacing rivets as needed since they are corroding. Last year I tried some 3/16 HDPE rivets (left over from a canoe repair project) where the rivet hole corroded too much to allow replacing with a 1/8 rivet. Those still look good a season later so I'll probably get some more of them. The curve portions are Al like the exterior walls and there appears to be something between the All and Galv all along the seam. My guess is it's there to provide electrical isolation to cut down on corrosion. The corner bits are all custom formed HDPE. Where your sheeting behind the tires appears to be stiffened by another sheet of metal on the inside, mine had a sheet of Nylon bonded to the exterior behind the tires. I presume this is rock protection. I've had to replace those since the glue failed a few seasons ago and the Nylon sheet was flapping in the wind. I ended up replacing that ~1/16 Nylon with several much thinner sheets of HDPE laminated. Doing it this way allowed a better bond area since I could use a small roller to work the bubbles out of the epoxy for each layer. So far, no delamination.

That's very interesting. I was able to cut the the vulkem that laminates the outer and inner Al on mine enough to use a welders gauge to measure the inner Al thickness. Somewhere about 19ga. I've ordered some 18ga 5052 this morning and will be able to pick it up after lunch.