Step 1: Description:
I made it out of 3/4" exterior grade plywood that I purchased from Lowe's.
(1) 4x8 3/4" exterior grade plywood or Marine Grade if you can find it (not at Lowe's or Home Depot) $33
(2) C-shape wall brackets for adjustable shelving. $10 each
(12) #10 x 3/4" metal screws, flush mount ( I only used needed 8 screws total, depends on length of rail)
1 quart of rust-o-leum truck bedliner coating, $21 walmart
Step 2: Measure Three Times, Cut Once
I decided to create two panels, each measuring 62" x 22 3/4".
I had Lowe's cut my 4x8 (easier than hauling and then setting up my tablesaw).
First Cut: Cut the 4x8 to a length of 62". Save the smaller piece for a future project.
Second Cut: Cut the 62" to a 22 3/4" width
Third Cut: Cut the remaining 62" piece to 22 3/4" width.
Fourth: Save the remaining 3" x 62" piece for use to support the seam between the panels.
Step 3: Install
Attach the C-shape brackets to the bedrail with the metal screws. The brackets have screw holes every 10 or so inches. Use clamps to hold them in Place while you install the screws at each end. I installed the brackets to be flush with the top of the bedrail.
Cut the 3" x 62" board in 7 equal lengths. And screw them to the underside of the each panel. Stager the boards on each panel in this way the seam is supported.
Step 4: Paint
Use a small 3" whinnie roller with a short nap so that the roller doesn't absorb much coating.