03-14-2012, 07:46 PM
Depending on how you design your support, your plywood thickness may not be critical. Galen (Ocaliecreek) here at Big Blue, built a small time saver layout and brought it to one of the modular club meetings with a power pack and a Bachmann GE 44 ton switcher and a few freight cars for some of us to play with after one of the meetings. He used 1/8 inch luan ply for a top with no foam, and it was plenty strong enough for HO scale. The secret was that he had cross members supporting the top on 12 inch centers. Depending on what you are building and how you are building it, you might find a thinner ply better for a particular application, or you might want something heavier. You might even find a combination better, with lighter construction for say a lift out section of lift bridge and heavier construction for permanent bench work. The secret is to support it appropriately for the thickness of the top material.