My work bench is a sheet of plywood. When it gets cruddy, I flip it over, then new sheet. This is more of an assembly table. If you plan on doing more hand work, something more substantial would be better.
I'd go with 1/4" as long as it is good and flat. The heavier it is, the flatter it will lay under it's own weight.Thanks, everyone.
From the several replies, it appears that the cheapest and easiest route for me will be to belt sand the high spots of the old 2×10 boards and attach a sheet of tempered hardboard (Masonite?) which when waxed will resist glue and paint sticking but still not be so slick that work pieces slide around too easily.
Would it matter whether 1/4" or 1/8" hardboard?
So how big of a planer do you have access too?Some great advice here. I'm leaning toward a 2×4 flat or stacked on end, glued and screwed or dowels. Then bringing it to my friend who sands floors and having him sand it smooth. The 42" is far too wide for a planer and Way to much work hand sanding the edges.