I recently bought a horse van box on Craig's List, then, found  (also on Craig's List) a chassis cab to put it on. 

The box is anywhere from 20-30 years old, and, thankfully, aluminum so it is in pretty decent shape.  It's had a few casualties where it looks like something backed into it.  One panel in particular has one large hole that has been patched via a welded aluminum patch.  It also has a hole that allowed you to get to the old fuel tank and another hole that was patched pretty haphazardly with screws.  Very 'Frakenstein-like'. 

Has anyone ever replaced aluminum skin?  If so, where did you get the panels?  I realize much of this would be custom-work but I'm trying to get edu-ma-cated.

Thanks

Over the years I've replaced numerous aluminum panels, extrusions and parts; not by welding, but riveting. A search on google for aluminum suppliers will result in many choices. Locally, depending on where you live, a fabricator may be able to supply what you need. The difficulty arises when the panel you need has a particular shape that is not readily available. Custom fabrication work can become expensive, where as sheet work is sold by the sq ft.

6061 T-3 works well for panels, if you need structural repairs 6061 T-6 is often preferred. If you need to bend any of the panels, you might try some 5xxx series aluminum. Many panel repairs can be made using doublers and an insert. Any welding will take particular skills, and unless the repair is painted, it will always be scarred, regardless of how well it was ground, faired and polished.

You might consider involving a body shop or truck stop that knows aluminum repairs. A local FBO (fixed base operator) can direct you to an aircraft repair person. Better marinas also repair aluminum structures. Many RV dealers also conduct repairs.

A little research should get you the info you need. BOL

Excellent information.  All of my aluminum is flat - no turns.  The curved parts on the box are either aluminum posts or corner caps  (I've since found replacements for these online).  Everything is riveted.

Thinking this will be an easy (albeit expensive) fix.