I am using L girder and open grid bench work. I can use plywood or OSB for the sub road bed, or make spline roadbeds. Spline is time consuming and once made, hard to adjust (I imagine). It would be the least likely to warp in our beautiful Georgia humidity. I am just not sure which way to go. OSB or particle board might be hard to attach things to that have to be nailed or screwed. Plywood has a nasty habit of expanding and contracting with the seasons. Got any suggestions???
Hi, Of your three choices I would go with Plywood. I personally would like to have a spline road bed but as you stated it is time consuming and hard to make changes to. Jamie AKA [FONT=Trebuchet MS, Georgia, Verdana]CSXDixieLine[/FONT] can provide more info on spline roadbed since he is using it on his new layout. I believe that the OSB will wrap more then plywood and particle board has a problem with being hard to nail into and does not like getting wet. This is just my two cents worth and if you want you can give me change. Gary
Launa plywood I use a good grade of Launa plywood (5 to 7 plys) for my roadbed. I prime it on all sides before I install it. The primer will help keep it from warping.
Continuing material science advances in OSB manufacture give OSB better flatness, stability, and stiffness than equivalent thickness of structural grade plywood panels. You can see it readily at the lumber yard. There is no such thing as a warped new OSB panel, but new plywood can be pretty wavy. The plys in exterior grade plywood are spiral cut and pressed flat. As moisture content changes, the uncurled wood plys develop internal stresses that deform the whole panel. The wood wafers in OSB are small enough that internal stresses in each individual wafer are insignificant. Similar to the crossed grain of adjacent plys in plywood, the wafers are oriented in layers with their grains crossed. OSB generally doesn't contain weak wood fibers or structural defects; those materials don't typically make it through the manufacturing process. However, plywood can contain voids and knots. The wood grain around knots can be especially prone to internal stress, as you may have seen if you've ever ripped lumber on a table saw. If you purchase cabinet grade plywood, you can get some very nice, very flat, high quality panels. However, the premium price is hard to justify for holding up a few ounces of N scale trains. I suggest you build a sub-roadbed using masonite splines or OSB, then place pink or blue styrofoam insulation atop the wood roadbed. The styrofoam won't expand and contract near so quickly as the wood will. Let the interface between the foam and the wood sub-roadbed accommodate the expansion and contraction; don't glue the foam to the wood - use drywall screws instead. Glue your track (with or without cork roadbed) to the foam for a dimensionally stable result. And, of course, provide sufficient expansion joints in your rails to prevent buckling during high heat.
CeramicTile At my wife's insistence I just finished laying 13x13 porcelain tiles in the train room. She said that it would be much easier to keep swept, moped and cleaned up with tile. Jeeze, I hadn't planned on cleaning!!! Going to have to make sure I don't have any derails that hit the floor. It will make finding that coupler spring that went sproing a little easier.
I will admit I have little or no use for plywood of any grade. I prefer the particle board 3/4" thick. In all fairness I must warn you that untreated particle board will absorb moisture. If you live in an area with high humidity you will most likely want to steer away from particle board and look seriously at plywood, a high grade plywood. I discuss this in one of my construction albums on RailImages. You can follow the invite below and see what I did. There is no such thing as a right way or wrong way. It's simply what works best for you in your environment. Here in Big Bear Lake, CA the plywood tends to warp badly and that doesn't make any sense at all considering the lack of humidity. I'm beginning to think plywood needs a little moisture in the air to remain flexible.
If you painted all exposed wood surfaces with a flat latex paint, you won't have any problems with warping.
