At first, I was kinda incredulous ... but now I'm not so sure?
Now, if you're using 0.063 magnesium sheets you won't be saving much in weight compared to standard 0.032 or 0.040 aluminum. And besides, a 0.032 sheet of 4x12 aluminum weighs - what - 25 or 30 pounds? Magnesium is just 33% lighter than aluminum.
Preventing galvanic corrosion between the magnesium siding, the trailer frame, any aluminum trim, fasteners and brackets might be a hassle. ..
But if you can figure out a way to prevent galvanic and atmospheric corrosion (metal polish or paint), then for $30 for a 4x12, I don't know if I'd pass it up for a one-time build.
You should do it and tell us how it fares in 5 years
