did that, good idea.
I built a wood flatbed for my '65 dodge (300 or 500) truck.
It was a long time ago, and I don't remember if there even existed treated lumber, but I painted all the wood with some kind of penetrating protector, IIRC, to waterproof and prevent mold and bug infestation, all well dried before I started work.
To do it today, I'd use all pressure treated wood, stainless fasteners, diamond plate on top, and (most notably) full fenders on the rears. Over the years, the bed top wore as to be expected, but the bottom of the bed suffered over the tires. I'd use fenders to look like the full fenders on old peterbilts rear duals. I had made the perimeter as strong as the frame rails to hold the side rails. I sold it to my brother-in-law to use on his ranch, and he sold it to another rancher down south. I saw it around 10 years ago with a water tank sitting on my old frame rails. The cab was well perforated with rust, but those rails were fine.
The stuff I used on the wood is probable illegal now, as too toxic, like DDT...
I think you weren't supposed to ever breathe the fumes, or even smell the smoke if you burned the wood that had been treated.
Thinking more about it, I asked wifey. She said I swore I'd never do it again, and should have bought a metal bed. I didn't remember that, but it sure looked good.
