MDF Baseboard

"RJR" wrote in news:TB6Hi.44688$ snipped-for-privacy@newsfe5-win.ntli.net:

I've used MDF on my last two layouts - first not finished and second is still being built! The second layout's in an un-insulated, draughty garage and has been there for about 3 years now, properly supported with 2x1 I've noticed no sagging throughout this time.

I've been very pleased with it. Doesn't warp or sag with normal support. Only cons are the same as chipboard: it's quite heavy and it's too hard to push track pins in. So I glue cork sheet to the MDF and glue the track to the cork, both with diluted PVA.

The question is really dependent on a number of factors including how resilient you want the layout, whether it has to be as cheap as possible, Whether you want the layout to be very light/portable and what sort of scenery you will use.

The lightest wooden technique is probably very thin plywood over a thin playwood box frame. I built one once with about 4 inch verticals and braces every 12 inches or so, the trick was then to use fibre-glass and resin to make the internal corners of the structure very rigid. This was very light but require some good clean cutting of the plywood and some mess with glue guns and resin.

MDF is cheap and solid and as long as it is kept reasonably dry then it tends to last ok. One problem as I found on some boards I had made was that it is very heavy and will be annoying if I take the layouts to shows, especially since they live in the loft and have to get out the hatch. This is probably the easiest to to build with some 2 x 1. As already pointed out, yu will have problems getting pins in but could glue the track down.

Some people use insulation board which is like pin board and accepts pins very easily but is also easy to break and doesn't leave clean edges when cut.

I have some other ideas like polycarbonate on aluminium frames but these are related to what you know, what you can get and what tools you have to cut such beasts.

If your scenery is very hilly then some people advocate the L-girder system which means you don't have a base board as such but an open frame. Onto this frame you then attach vertical supports and then thin strips of plywood to form the trackbed. This makes the layout very light and makes it easy to get gradients built. Obviously this is more involved and requires much more woodwork and cutting.

Luke

Any sheet material will sag when laid flat. Stand the MDF on edge and there will be no measurable sag! IOW MDF like ply etc etc will need a frame. MDF is a little heavier and not as strong as ply for any given thickness. OTOH weight is very little disadvantage and has the postives of reduced vibration, reduced sounding and more stability. The amount of framing/support is going to depend on the thickness of the MDF you use. For 6' x 1'6" (1800x450mm) I would use 12mm thick MDF on 70mm x 24mm pine perimeter frame with a cross piece at the 900mm midpoint. I would also add a 12mm thick "Pinex" top surface to give further sound-deadening and to enable ditches and low lying areas to be cut out later. I glue and screw everything.

(Pinex is a softboard, like your Sundella but softer)

Greg.P. NZ.

IMO MDF is too heavy. 6mm and 12mm ply used in an egg-crate style of frame will be both stronger and lighter than MDF over 1x2 or 1x3 strip lumber.

Actually, a used hollow-core door would be ideal for your purpose, if you can find one. It will be both stronger and lighter than a piece of MDF the same size. Folding wardrobe doors come in the size you want - two of them fit a 3-ft wardrobe opening.