Hold the foam???

Discussion in 'HO Scale Model Trains' started by Doug, Oct 18, 2006.

  1. Doug

    Doug New Member

    I am starting my first layout and was planning on putting 2" of foam onto the plywood before laying the track. PPl at the LHS tell me not to use foam under the track but how else to you make the substrate have different elevations. Do any of you put foam under your layouts? If so; do you expanded or extruded polystyrene?

  2. MasonJar

    MasonJar It's not rocket surgery

    Use extruded (pink or blue), not the expanded white "beadboard" type. The extruded stuff is much stronger and cleaner to work with*.

    * Unless you sand it - then you're on your own...! ;)

    At the modular club (www.hotrak.ca) we use 2" foam set in a 1x5 pine frame, usually with a crossbrace every 24 inches or so.

    MR had an interesting article a while back about using a hot wire cutter to carve the roadbed profile right into the foam - no cork required!

    Did the LHS staffers say why they would not use it??

  3. LoudMusic

    LoudMusic Member

    Whoa, double the Andrew, double your pleasure. Double Mint Gum!

    I like this idea of making the roadbed out of the foam. Save a bit of cost there for sure! Any help on narrowing down where that MR article is? If not I can probably scour their site for it.
  4. MasonJar

    MasonJar It's not rocket surgery

    What? Me? I never make mistakes. See above... just ignore that "Last edited by..." stuff.

    I can narrow it down - it's in my basement somewhere... That's accurate to plus or minus about 10 metres...! hamr

    Basically the guy made a custom cutter in the profile he wanted, and used an old powerpack to heat up the wire to the point it would melt through the foam. Definitely an activity for outside, and you'd probably want a respirator anyway...

    I've drawn a sketch from memory (MS Paint, not SketchUp :(). I think he used something like piano wire that was bendable, but strong enough not to flex too much when cutting. The red wires run to the variable out on the power pack. The green dot indicates where he put a short piece of wire sticking out perpendicular to the wooden handle (grey box) to use as a guide to follow the track centreline. The blue edge rides on the surface of the foam, and becomes the top of the ballasted profile.

    You can shape it anyway you like - I've tried to draw a shape that shows the ballast profile, and a drainage ditch on either side. I also make no claims about how to wire this up - I have no clue. I did build a hot wire cutter with nichrome wire, but it has enough resistance to heat up and/or not cause a short. I don't know about piano wire.


    Attached Files:

  5. LoudMusic

    LoudMusic Member

    Ah, good stuff. MS Paint works just fine for this representation ;)

    I guess similar jigs could be made for sculpting cliff facings and such. I'll have to find more info on the hot wire hardware. Like you say, the wire needs to be able to heat up and also not bend. I'd bet there's a custom tool for this, but surely one can be made on the cheap.
  6. Doc Holliday

    Doc Holliday Member

    Doug, I did exactly what you're talking about. I put 2" of white foam (I can't find the blue/pink syuff in my area) over 1/2" plywood. I then added WS inclines and home made risers to provide different levels. I've also cut away th ebottom 2" foam in some sections (down to the plywood) to great the appearance of more elevation change.
  7. TrainNut

    TrainNut Ditat Deus

    You know I used to be a die hard, cookie cutter, if it ain't nailed to plywood, it's gonna fall apart. Then, I did a couple coffee table layouts using foam and glue and I joined a club that used benchwork topped with foam. It's kinda cool and a whole lot easier. Now, for the first time ever, I have decided to build my current layout via the benchwork/foam method. I only put one layer of foam on the bottom but my supports are every 12 inches and I've got a canyon that dives down 10 inches below the main level of the benchwork as well as two levels that are going to be separated by 6 inches - plenty of elevation differences for me. Check it out in this thread...
  8. ocalicreek

    ocalicreek Member

    I second the question...what did the guys at your LHS have against foam?

  9. Jim Krause

    Jim Krause Active Member

    I haven't used anything but pink and blue foam since the 1970's when I built a 4X8 toy train layout for my son. Our club layout is all foam except the mainlines which run on a high density particleboard base. My logging line is entirely pink and blue foam with the grades cut into the foam and cork roadbed over the foam. It does take a bit of work to get a constant grade in the roadbed.
  10. Doug

    Doug New Member

    At the LHS the objection to the Foam was that you have to glue everything down. Nevertheless, I have decided to go with the opinion of the Gauge and use foam. I have built the bench with 1X4 and put joists 1 1/2" down, then inlayed 1 1/2" SM to bring it back to level to start. Now I have the option of going up or down.

    One other reason I decided to use foam is because I have a shope that sells foam board, adhesives and spray foam. :D
  11. ocalicreek

    ocalicreek Member

    That had been my fear as well. When I used foam, it was the white bead stuff from dumpster diving expeditions. My layout was basically a tabletop (ply over butt joint framing) with foam risers and 1/4" paneling from a room remodel on that. There's a caulkgun-style adhesive specifically for adhering foam to paneling and it works great.

    But I wasn't ready to glue roadbed and track down. I bought cork in sheets, cut it and beveled it with a carpet knife, then nailed down both the cork and flex track. With nails I knew I could go back and realign the track if need be without much fuss. With glue you're stuck, so it better be right the first time. Although, I have heard that some adhesives will move when gentle heat is applied, like from a hair dryer. Guess it depends on what sort of glue you use.

    I've also heard great things about the Woodland Scenics risers. Talk to Steve (Nazgul) about that.

    What sort of adhesive will you be using?

  12. scubadude

    scubadude Member

    I have been looking at The Gauge for a while, and this is my first response to a thread. I am currently working on my first "real" layout in N and have tried the Woodland Scenics foam risers and 2% grades risers and it is super simple and effective. Just don't go crazy with the hot glue gun. If you put only a minimum amount of glue on the foam risers, you can scrape off any mistakes with a 6" tape and bed knife. I will try to visit you all more soon.
  13. Doug

    Doug New Member

    I am using PL300
  14. fsm1000

    fsm1000 Member

    I have a tutorial on putting foam on plywood, how to glue it, cut it etc etc. Hope it helps you out . :)
  15. Nazgul

    Nazgul Active Member

    first of all, welcome to The Gauge:wave:
    I'm not sure I can add anything that hasn't been said before...but that never stopped me before!:D
    I used the 2" foam on top of my plywood. I glued it down with "Liquid Nails for projects" worked good...little odor...definitely a big plus. I just read the the tech data sheet for PL300 and it looks like it will do the job perfectly:thumb: Might want to see about any fumes it will or will not create...just a thought.
    I've used the WS inclines and risers and couldn't be happier:) I drew the track plan on the blue foam and pinned the inclines and risers in place and glued the edges with a low temp glue gun. I used white glue to attach cork on top and used track nails to keep the track in place. Ballasting will eventually glue the track down permanently. You can see pics on this page of my thread: (if you look close :eek: you can see the pins and hot glue)


    I'm sure this is more info than you were looking for...if it is, then.......never mindsign1 good luck and post your progress:wave:
  16. jbaakko

    jbaakko Active Member

    I love the WS risers, BUT I found they're not very consistant on thickness, 1/3 of mine were 1/16" taller then the 2" they were supposed to be. Thats a BIG difference when butted between 2" risers...
  17. jcoop

    jcoop New Member

    I have used foam in the past and it has it's good points for sure. It is light weight, easy to work, and you can do almost anything with it.

    The downpoints I see are: Can be dented up and the cost. Here in Northern California a 2'x8'x4" is $2.15 a square foot (ouch). I used it on my last layout and I thougth it was noisy.

    Home Depot has a soundproofing board that is under $10.00 for a 4'x8' sheet. I am thinking about a cookie cutter set up with this sound board over 1/4 plywood. I am thinking about doing a test section in the next week or two. (I hope)

    just my .02

  18. pgandw

    pgandw Active Member

    I would be suspicious of the sound board over the 1/4" plywood not being rigid enough without closely spaced supports. The foam is quite rigid on its own; when combined with plywood it does very well. But 1/4" plywood on its own will sag between supports at 16" spacing, and so will the sound board. I don't think laminating the 2 will gain enough to make a difference. 1/2" plywood would do a lot better.

    my thoughts, your choices
  19. jasonboche

    jasonboche Member

    I did the same as Nazgul. 2" pink extruded foam on plywood. Secure with liquid nails caulk.

    A 4x8 sheet of 2" thickness here in Minnesota is around $17.75/ea. Not cheap but if you want cheap, you're in the wrong hobby.
  20. Gil Finn

    Gil Finn Active Member

    I suggest getting a tape or book such as woodland Scenics sells the first time out.

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