Plywood is a simple material, very versatile and great material for a model railway baseboard top. Here’s what you need to know before buying.
What is Plywood?
Essentially, it’s a manufactured by gluing together thin slices of wood with each layer rotated so adjacent grains in the layers don’t run in the same direction.
The rotation of the sheets, known as cross-banding, is key to its benefits for a model railway baseboard.
By rotating each sheet so its grain runs in a different direction to the adjacent sheets plywood is less prone to expansion and shrinkage than other boards and helps ensure the track mounted on it stays flat and level.
This reduced tendency to shrink and expand is why I use it over other types of manufactured board such as MDF and chipboard.
The rotated grain also gives it great dimensional stability making the board strong in all directions.
What thickness should you use?
Plywood is available in different thicknesses from 3mm to 24mm, I’ve even seen it sold up to 32mm.
The thicker the plywood the stronger so why not just get the thickest you can?
For model railways there is one key reason.
The point motors that sit under the baseboard and operate the points have a metal pin that passes from the motor through the board and into the tie on the point.
Typically, these pins will only reach through 9mm or 12mm boards.
And while you can extend them, which I did using Piano wire for my Tortoise motors, but why bother if you don’t have to?
Thicker boards also cost more and weigh more so need heavier grade in the legs and cross supports.
Before using: things to check and do
Once you’ve got your Plywood there are few things to check before jumping in and building your layout baseboard.
- Inspect the edges and sides. Watch for edges that don’t have uniform thickness or gaps between the layers.
- Paint the surface and underside. Not strictly necessary but painting the top surface and underside can help later. See making wiring easier with a splash of paint and should you paint a baseboard.
- Seal the edges. To prolong the life of the plywood, seal the edges with a wood treatment. Some people suggest PVA but this is one of the few occasions I don’t advise PVA. You want to prevent damp getting into the wood and PVA softens when it gets damp which invalidates the whole point of using it. Instead use something like this wood treatment.
CE Marked 9mm hardwood Plywood with home delivery or click and collect is available from B&Q here.
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