[wglord]

I make mine out of plywood (1/2 - 3/4)with 3/4 inch cleats and then cover with aluminum flashing. Form the flashing to the cover and staple to the side and cleats. I get 10 years out of them and they are cheap and impervious. You will need some practice to form the flashing corners - it is like gift wrapping - and cut the flashing with a utility knife once you figure out exactly what size you need. If I get a hole in one I staple the hole down and apply a glob of caulking. Simple, cheap, and impervious.

 

[Birdman]

I use the cedar fence boards for my telescopic covers. Migiary covers might be a little diffrent. cedar likes to split bad. If you are putting metal on them it will not matter

 

[hemichuck]

I've been making my covers out of 3/4 plywood shelves I had laying around.I can cut them in half and make 2 covers.On some I glued and stapled door shims on the bottom to make top entrances(Michael Bush Style)and I took scraps from other projects and stapled a 3/4 by 2 board down each side to keep them from moving side to side.The others(telescoping covers) I just used scrap 1 by lumber to make my 4 sides and glued and stapled them on.On all of them I have been taking old political signs(usually free in May and November) and glueing them to the top with spray on contact adhesive(for car headliners) and then I paint the plastic signs whatever color I have handy.The signs seal the top from water and since they are corrugated a little air moves through them to keep them from sweating.

 

[MapMan]

I make 'em out of used concrete form plywood (marine ply). No metal, no paint. Costs me less than $1 a cover, have lasted so far 5-6 years. Easy and cheap.

MM