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FOAM

Posted: Mon Mar 15, 2021 12:45 pm
by SEMI
i have noticed a lot of pepole put down foam on top of the plywood platform...i have 2 questions...why put the 1 inch foam down to begin with, and if so how is the track secured so it doesn't move?

Re: FOAM

Posted: Wed Mar 17, 2021 6:37 am
by scenicsRme
1. Plywood over an open structure makes an excellent acoustic amplifier, so running several trains with track mounted directly to the plywood can get surprisingly loud even without sound effects. The foam acts as a sound barrier quieting the layout down to the sounds you want to hear.
2. Even a large yard in not perfectly flat! There are drainage ditches cut in between the tracks so the tracks and ties do not sit in water. The 1" foam allows you to use an inexpensive hot foam cutter to cut in similar drainage troughs between your tracks for a more prototypical look. Try using scale size ballast for the track, and a thinner layer of finer grind ballast stone and/or even of a slightly different shade for the area between the tracks where sand and silt would tend to accumulate. 3. the foam give you the option to mount your track directly to it or to add roadbed between the track and foam, Again for a prototypical look I would suggest using roadbed for the mainline and direct to foam for yards. You can use a thin layer of inexpensive latex caulk to glue down the foam to the plywood, use the same to glue your favorite roadbed to the foam and finally another thin layer of the caulk to glue the track to the roadbed or to the foam. No more bashing the track with a hammeror putting in humps and bumps trying to nail down the track, A few strategically placed push pins between the ties fto temporarily hold the track in place, a few boards and weights (full water bottles laid on their side are ideal!) left overnight to dry completely and you are done.
3. The foam makes an ideal base for scenery work. It takes inexpensive latex interior paint very well. Hint: check out the miss-mixed paints available for a significant savings at your local paint or big box DIY store paint department. One thing to remember, mixing several different colors together, the more different they are the better, will invariably produce some sort of shade of brown! You can always darken it by add a small can or two of black, dark grey or dark brown (or blue if too reddish, red if too bluish or greenish). Many stores give away small cans meant for testing a color at home you can add to your brew. The base color doesn't even need to be the same throughout, just blend the changes wet into wet to avoid a hard edge. You can also layer additional foam to build up areas then carve into the foam directly or cover with a plaster or sculptamold layer to blend. Want trees? Just poke a hole with a rod or skewer into the foam, add a drop of tacky glue and plant away. Grass and ground cover is just as easy, since the foam does not absorb moisture, just brush or dab on some wood glue diluted 50-50 with water where you want it and sprinkle on ground cover and/or use a static grass applicator. 2mm green static grass applied evenly will give a lush front lawn. A mix of several lengths and shades (throw in small amounts of yellow and brown longer lengths for a natural look) applied unevenly will give a wild meadow look.
4. Even a 1" deep river or creek channel cut into the foam can be made to look like a shallow swamp, a meandering creek, a raging river, or a deep lake, There are dozens of videos out there than show you how, and water always adds visual interest to a layout.
5, If you are modelling in HO, N or Z scale, you can use a 2" thick layer of foam on top of a 4' apart wood support grid and leave out the plywood all together!

I'm sure others will add their reasons for using a layer of foam.

Re: FOAM

Posted: Thu Mar 18, 2021 2:30 am
by SEMI
well, i guess i'm old school, because all i put on the plywood is grass paper...i love the sound my 2 sets make running on the platform...ans second,...i would "never" glue down my track...how could i re-use it?...it's too expensive to just glue down and forget ever using it again...but i guess everyone has their own preferences...

Re: FOAM

Posted: Sun Jul 18, 2021 3:10 am
by scenicsRme
That's the beauty of using the latex caulk as an adhesive for track laying to foam or roadbed. You only need a thin layer of the caulk, run a small bead down the track centerline and spread it by dragging an appropriate size putty knife or plastic scraper (hint: old credit cards make good scrapers and can be trimmed for width) until there is only a thin layer left, you should be able to see the surface beneath and it doesn't need to be a perfect width of caulk. Press down the track, the caulk should NOT be thick enough to ooze around the ties and weight and/or pin until dry (overnight). Now should you need to lift a section of track, just slip a thin putty knife under and pry slightly. The track will pop loose, ready for reuse, leaving almost no residue on the track. If you use roadbed on the foam the same application and removal technique will leave most reusable as well (cork will dry as it ages and become brittle, but that is a characteristic of the material not of using caulk as an adhesive.