I'm planning on building a N scale railroad on a sheet of 4x8 plywood. I
keep reading about the blue foam sheets but don't understand the advantages.
Could someone enlighten me on the pros and cons of using the foam?
some guy wrote in news:ORG2k.13909$gc5.2079@pd7urf2no:
Here's some cons:
-Doesn't hold track nails well, so glue is required.
-Cutting can be messy, or very smelly. (Depending on the method used.)
-Easily broken, so portable layouts require additional supports.
-Plaster doesn't stick as well to foam as it does wood. (I get around
this by gluing cheese cloth to the foam and then adding my plaster.)
-Sensitive to glues and paints.
-Takes acrylic paints well (especially the Apple Barrel colors that are
available for around $0.44 a 4 oz bottle.
A couple other thoughts, not Pros or Cons:
-A hot wire foam cutter helps cut through the material, and you can make
one for next to nothing. (See the directions posted at:
-You don't have to use foam for your track bed. If you do this, you can
use pine boards to spike your track down and still have the foam for
There's been debates on rec.models.railroad in the past regarding
flammability and noxious fumes if it catches on fire. The spirited debates
on the topic was an indication that the jury is still out on how serious
that con might or might not be. But the individual modeler should at least
consider that aspect. You can read more by searching the
rec.models.railroad archives at
Joe Ellis wrote in news:synthfilker-
email@example.com: *trim and snip*
What I meant by that is that replacing the plywood with foam is generally
a bad idea for a portable layout. It might work with a permanent one,
but portable ones need that extra support. (It's not easy to say
everything you want to say when doing a "cons" list.) *snip and trim*
Agreed. I'd also like to recommend using a CAD program like XtrakCad
that allows you to run virtual trains before you start building, to get a
feel for how your layout will operate.
Seconded. It's a wonderful material! It's very quick, too -- see last
paragraph below. BTW, there's also pink foam, which is softer and easier
to work with, and black, with is denser and breaks in patterns that are
very rock like. Do not use white bead-board!
I've found the easiest way to cut the foam is with a paring knife, or a
bread knife for thicker sheets. Mark the desired contour, insert the
knife at an angle, working your way along the contour two or three times
until the piece falls apart. To make rock faces, slopes, etc, insert the
knife at an angle and twist. Keep the knife sharp. Don't use a saw, they
make too much dust, and don't use heated wire cutters, the fumes are
toxic. There is very little waste - all the scraps you cut off can be
used to build up scenery.
For track, mark out the centre lines, and glue cork in place. Use
water-based latex glue, the thin kind that comes in pint cans. You can
pin the track to the cork temporarily until you've ballasted it - the
glued ballast will hold the track in place, and then some.
For scenic cover, begin by using plaster impregnated cloth. Buy the
cheapest available (usually at art supply stores.) Cut into
approximately 4x6 rectangles, dip into water, and apply. Very clean and
fast. Add rock castings etc as desired. After the plaster has dried,
paint all over with cheap latex paint in a sandy or rock coloured shade,
paint with washes of acrylic craft paints to get variety in rock colours
and earth colour under "grass", and apply ground cover etc as usual.
If the layout is to be portable, make a frame of 1x2 with crosspieces at
about 12-16" centres, glue a sheet of 1/4" ply onto it (the cheapest
floor underlay is more than adequate), and glue a 1" foam sheet onto it.
Use a water-based latex glue. I've used construction glue in tubes, but
find it's too thick, and have looked for and found thin latex adhesive
in cans. I apply this with Popsicle sticks, or spatulas made of scrap
wood. Apply to both surfaces, wait about 5 minutes, and place foam
sheet. At 5 minutes, the glue is still workable, so you can make minor
adjustments, but locate the sheet as accurately as possible. Place
weights on top, and let set overnight. this will be the base or zero
level for the layout.
To glue pieces of foam to build up scenery, use the latex glue as a
contact cement. Apply, wait 15-30 minutes, and stick together. The bond
is instant, so test fit the pieces before you glue them. I also add a
couple of register marks when test fitting. to ensure the pieces go in
place as planned.
I built a 32"x48" N scale demo layout for a trade show in 7 days,
including one day waiting for the plaster cloth to dry, and working less
than fours a day! It was incomplete, which was actually an advantage, as
it showed visitors the stages of building. Adapted from "Oyster Bay" in
_101 Track Plans_, it has a tunnel, a bridge, a bay, a passing track,
and two spurs. I'm puttering away at it.
Like anything else in life, there are plenty of exceptions.
I agree that 3 feet is a practical limit for any layout up
against a wall. In this case though, foam construction
makes it a lot easier to pick up the layout and move it to
the center of a room so that you can work on all sides.
One *minor* nit: the foam comes in (at least) two colors:
Blue is made by Dow (and others).
Pink is made by Owens Corning -- all of Owens Corning's insulation
products are colored pink -- their trademark / mascot / spokes cartoon
(?) is the Pink Panther.
The Pink and Blue foam is the same material: building insulation foam,
commonly used to insulate foundations and/or poured concrete building
walls. Getting the stuff can be problematical in warmer climate areas
(eg Southern United States, etc.). It is commonly available at
building supply places (Home Depot, Lowes, local lumber yards, etc.) in
colder climate areas (eg New England).
One thing I've never understood is that people think you need insulation
only to keep heat _in_. It's just as good at keeping heat _out_.
Air-conditioned buildings need insulation just as much as heated ones,
if not more. I know the first thing I'd do if I ever move to southern
Texas (where one of my daughters lives) is insulate whatever house I
buy, add a heat exchanger / ventilator, and a ground effect heat pump.
HTH those of you who live in those hot places. ;-)
Better yet, add a double layer roof, use white or light colored standing
seam roof panels over a continuous air gap from soffit to ridge, with a
continuous venting ridge cap. Inside the inner sheathing put foil-faced
rigid foam for radiant as well as conductive insulation.
I sometimes think I'd like to have a heat pump, but know a lot of folks
around here who've had less than satisfactory experience. We just had to
replace our furnace (cracked heat exchanger), and while we were at it
replaced the twenty year old A/C, originally a nominal SEER 10, surely less
now and prone to problems as well as noisy. The new one is 19.5 SEER, has
dual compressors (large and small) and is much quieter. The furnace is 95%
efficient, and with a max exhaust temp of 114 F, they have to use poly pipe
for the "chimney" - metal would rust out.
this is not in the spirit of "foam", but works quite well for me:
I built the usual wooden frame with plywood on top. In the hilly areas I
used packaging carton and plywood leftovers to model the terrain
contour. The track bed is assembled from a thin cork plate, cut into 7mm
stripes and glued down three stripes for each track. The terrain itself
is made from old newspapers, cut into small strips and glued down using
the glue offered for wall-paper (don't know the name). After a few
layers this gets real stiff and can be finished using (a small amount)
of plaster (or anything like plaster, probably plaster with sawdust?).
The whole thing is quite easy to work with (drill, sand, saw...) and you
can simply cut the paper if you don't like the form (before the plaster ;-)
Actually my layout consits of two parts, the back part is placed in an
open cupboard and the front part hinged and removable ;-)
As to fire-safety, I don't think plaster burns that well ;-) Thanks to
the stiff paper the thing stays reasonably light and is stable for
movin' around a bit.
Total cost (for my 150x80cm - that's about 5'x3' - layout):
- wood: ~20$
- packaging carton: free
- old newspaper: free
- 1 or 2 pack of glue: 1-3$ each
- 5kg plaster: ~8$
- cork: ~5$
- colors, scenery, whatever ;-)
The only thing I'm still worrying about is the mountain-range in the
back. It has to be removable as to facilitate access to the hidden yard.
So I have to do a construction of some kind as a base for the removable
sections... At the moment I'm fitting infrared light detectors to the
hidden yard, so I'll know when a train is blocking a switch once it's
closed ;-) Signalling at it's best ;-)
Just to add my ideas ;-)
PS: Yesterday I did run my first train with the self-made control pult:
a "touch screen" for the switches and on-off-on switches for train power
combined with two throttles ;-) Nice thing... I had to short the "safety
circuit", though - it's not yet connected properly... It will only allow
train power, once both the front and back parts are connected properly.
Yes, I've thought of that type of cooling arrangement, too, I'd like to
know how effective it is.
Air-to=-air heat pumps have a relatively low gain factor, on the order
of 1:1.5 to 1:2. Ground effect heat pumps have gain factors of 1:3 and
up. Well worth while. Main cost is drilling what amounts to a well,
which will have to be 100ft or even deeper, depending on local geology
(water table, type of rock, etc.)
BTW, an air-conditioner is a heat pump. So's a fridge.
I have used this in the past for small layouts. The flammability of foam
is a concern, made more obvious to me when we built our home a few years
ago and used ICF (Insulated Concrete Forms) for the foundation. Our
building code (and probably most others) require that ALL foam insulation
be covered. Outside, that meant that the stucco finish on the house had to
go down to the grade line. Inside, that meant that ALL outside basement
walls had to be drywalled.
With that in mind, how many model railroaders plan for a field of blue
or pink? By the time scenery is finished, most of it is covered by plaster
or a similar coating. Even on flat areas, I usually used a thin "icing" of
plaster (rough up the foam surface a bit, and it holds quite well). The
underside is another issue, though. In my case, I was building a small
portable layout, so I laminated the foam to a half-inch sheet of particle
board, and the edges had counter laminate applied as a finish.
Here's a pro that I rarely see others mention:
Running wiring can be done on the surface: just score a cut where you want
it to go and use a small slotted screwdriver to stuff the wire(s) into
Check out Ice Energy's Ice Bear.
Excuse me, I'll be right back. I have to log onto a server in Romania
and verify all of my EBay, PayPal, bank and Social Security information
before they suspend my accounts.
Working the rockie road of the G&PX
On mine, I make all mountains removable. The mountains area a seperate
structure, and I place a couple of wooden dowels (to insert into a
corresponding hole in the base) in the bottom of each mountain to hold
them in place. In fact many of the mountains are made of multiple
sections for easy access to tunnels, etc.
Just place trees, etc. to cover any seam in the hills.
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