# Layout substrate



## G1-L Tech (Dec 7, 2016)

So, here I am again, I have built my layout table, it has 3/4 inch plywood on 2X4 framing, now, my question to you all is should I, or could I not use the foam(of any kind, or size), but just lay the plaster cloth down and build up from that, using foam,...etc, having said that, I would use the n scale cork road bed, then lay my track, has anyone done this? Do you think it's a good idea?
Thanks in advance.
Trev:smilie_daumenpos:


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## traction fan (Oct 5, 2014)

*Foam or no foam*



G1-L Tech said:


> So, here I am again, I have built my layout table, it has 3/4 inch plywood on 2X4 framing, now, my question to you all is should I, or could I not use the foam(of any kind, or size), but just lay the plaster cloth down and build up from that, using foam,...etc, having said that, I would use the n scale cork road bed, then lay my track, has anyone done this? Do you think it's a good idea?
> Thanks in advance.
> Trev:smilie_daumenpos:


G1-Tech;

No you don't need to use foam if you don't want to. Model railroads have been built without foam for decades. In fact, the use of extruded foam insulation as a scenery material is a relatively recent innovation. 
I'm not sure I understand all that you're asking. If you want to use plaster cloth to form hills you will need to give it some temporary support. Then you mention building up with foam. What's that about? (or a boot since you're Canadian )
Your train table sounds formidably solid, and heavy. Nothing wrong with that, but it may make it a little bit harder to create rivers, valleys, road underpasses, or any other below-track-level features. It can still be done, but you'll need to cut through that 3/4" plywood with a saber saw to do it. I don't know whether your table's frame is just around the edges of the plywood, or if there are 2x4 intermediate joists across it. If such joists exist, then Murphy's law dictates that they will be right in the way of that riverbed you want to cut! 
Old school layouts were constructed with "L-Girders" made of a 1"x2"glued edgewise to a 1"x4" these pieces formed an L shape, hence the name. Two of these girders, turned upside down, (to form inverted 'L's) were used as the structural supports; and tied together with 1"x3" joists every foot or so. The legs were2"x2"s and they were set in 1/5th of the L-girders length from each end and cross braced. The advantage was that all screw heads were accessible from below, even after the layout was completed. This made moving a joist, to clear a path for that riverbed, or whatever, was quite easy. 
The terrain was formed using a technique called "hard shell scenery." Masking tape and wads of newspaper formed the shapes of the main land-forms; both above, and below, track level. These were draped with paper towels dipped in wet plaster. (These were an earlier, and much messier, version of plaster cloth.) when the plaster had hardened, the towels and tape were removed leaving the "hard shell" of plaster behind. No foam was used.
You mentioned laying plaster cloth on the plywood, or other support, and then adding cork roadbed, and then track. The plaster cloth alone would not support the cork & track properly. The old school system used plywood "sub roadbed" cut to the desired track shape. This was supported on wooden "risers";(vertical 1x4s with a 1x2 across the top) that were screwed to the joists and to the sub-roadbed. If you want to have track above plywood level, you will need some similar sort of wood, or strong foam, support system. Plaster cloth and cork won't be either strong, or flat & level, enough to support track.

Using thick extruded foam eliminates all of the above! You can glue it to your plywood table top and glue the cork to the foam, and the track to the cork. Rivers can be simply cut down into the foam. Other, smaller pieces of foam can be glued in stacks and carved into hills. Personally I think that's a much simpler system.

Traction Fan:smilie_daumenpos:


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## DonR (Oct 18, 2012)

There is no real right or wrong about the
use of foam on your layout.

The surface of the plywood is not really suitable
for scenic effects. If you plan to have roads,
streets, lawns, fields and the like you will need
a smooth flat surface. Any thickness of foam will
do that, but unless you intend to create a river,
pond or other low point on your layout you don't
actually 'need' a thick foam.

I used the 1/4" thick paper covered foam from
Walmart's crafts dept. It comes in poster size sheets,
in black, white and other colors. I found the white better
for painting the base for grass or field areas, and the
black ideal to place under yard tracks and spurs.
It makes a nice smooth base for buildings. If you
plan hills, mountains or tunnels your plaster cloth
will meld into the foam easily.

You might check on it before you make your
final decision.

Don


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## Tony35 (Mar 18, 2016)

No you dont have to use it but as others have said creating a lower feature will be a lot tougher

Here is the cookie cutter method I used on my old layout
Need to plan way ahead for scenery 



Used the foam on the current layout
Much easier to carve and shape in features



HTH


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## G1-L Tech (Dec 7, 2016)

Thank You to everyone.Your explanations are VERY helpful, I now know exactly what I am going to do.


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