[jrmunn]

Adam - Since you mentioned it, this is a chance for me to let people know that using plywood is one of those seemingly good ideas that brings on a whole set of new problems, even if one keeps the bed straight, that make the use of planks a much better option. I know because I did it.

When I removed my old, falling apart original bed, I could see that there is a long, unsupported stretch at about the middle of the bed. Since plywood is strong in all directions and would sit on the high points of the frame at each side of the bed next to the unsupported center, I figured it would provide a stronger end product. And I think it has.

But using plywood while keeping the look of the original bed requires cutting it to fit (plus remembering that it needs to go far enough under the bed sides and tubs to provide support and bolt holes), cutting grooves in all the right places for the rails, and drilling holes of the correct size in all the right spots ahead of time. I can testify that this is a measurement nightmare (especially at the edges). Also, an 8 foot long sheet of plywood is shorter than the pickup bed, so an end spacer is needed. And, worse yet, I am not much of carpenter.

Then one has to worry more about water getting into the plywood because of both delamination and swelling. This requires much attention to painting top, bottom, sides, and holes - and then re-painting the bed to prevent leaks. Planks do not delaminate, sideways swelling is handled by the space between planks, and planks do not have much lengthwise swelling.

So the bottom line is that using plywood in a 6066 bed is not worth the trouble, or the maintenance, that comes with it.

If I had it to do over, I would have a new cross-member welded between the frame high points for planks to sit on and that could be used to install a center ball for pulling goose-necked trailers. This would probably get in the way of putting mufflers in the stock location, but mine was already moved forward years ago by a long forgotten muffler shop and seems to work fine under the front part of the bed as long as it isn't hitting the emergency brake cables.

There are other things to think about that go along with a bed replacement, like rust treatment and control, or if one wants to use the pickup for pulling trailers. But these are for a different thread, and this post is already too long.

jrmunn