Styrofoam On A Platform--Not Plywood On 2x4's

Pretty clever and ingenious, there are a lot of ways to build a layout , that is for sure. My only comment if you aren't using styrofoam (that is the crap they use in coolers and such), you are using closed cell insulating foam aka blue/pink/green stuff. Only reason I mention that is in case someone reads this and thinks they can use styrofoam, which is not suitable for this kind of use.

I build an open framed platform with the 1" stuff and it's like a drum head, really noisy. Probably should have gone with 2".

I didn't use extensive 2" foam, but I found a spot that it was useful in, some of the supports for my ramp to the second level.

I use thin sheets of pink foam to provide contours in otherwise "flat" areas--usually over Homasote. I do this primarily to let me carve areas that let me recess the ridiculously unrealistic bases of postwar accessories. I also use it to create subtle grades to break up the flat-tabletop look.

If it is structurally solid, and it looks to be with that Gorilla Glue, keep at it!  I love working with construction foam more than wood if I can.    Foam carving tools change the game as far a fun, in my opinion.  Not sure if you have any of those foam burning tools, but they work great.  Hot Wire Foam Factory's 6 inch "samurai" is my favorite tool.  Cuts like butter in pro mode.  Just have to make sure you have a mask and/or ventilation. 

I use the Hot Wire Foam Factory Scroll Table to make all sorts of small pieces.

@IRON HORSE posted:

If it is structurally solid, and it looks to be with that Gorilla Glue, keep at it!  I love working with construction foam more than wood if I can.    Foam carving tools change the game as far a fun, in my opinion.  Not sure if you have any of those foam burning tools, but they work great.  Hot Wire Foam Factory's 6 inch "samurai" is my favorite tool.  Cuts like butter in pro mode.  Just have to make sure you have a mask and/or ventilation.

What do you use for a power supply?  The tool is cheap, they want $100 for the power supply!

I use my transformer for the Scroll Table, works fine.

I bought the Pro Kit several years ago.   The transformer allows you to use all of the tools.  The tools that plug into the "pro" socket work much faster.  I labeled the tools so I remember what they are.  I also labeled the transformer because there is no arrow to tell you where you are when you turn the dial for different temperatures.  I have the scroll, too, but have not used it yet -- I have ideas for it though.  Glad to hear it's useful.

I used foam for my risers on the current layout.  My reusable Christmas layout is all foam.  I considered it for my permanent layout, but chickened out and used the old tried and true 'wood.'  I had almost enough wood on hand to build the layout, but I agree I like working with foam more than I like working with wood.  I think I will be using a lot more foam in the future.

I was supporting several lines of track on Sheet Styrofoam. I thought it would be easy to use, too.

But I found that the sheet foam has very little structural strength. All you need is a little bit of pressure and it cracks.

I replaced ALL of the sheet foam I used for track support with Masonite. I still use it for scenic spaces without track.

I feel safe with 1/2" Baltic Birch multi-ply and 1/2" Homasote, no cracking here!   I would not be at easy standing on foam, even 2" construction foam!

I'd be willing to bet that you could build a raft of 2" insulation foam and float your whole layout in a pool.

I Built a 6X12 modular frame and use 2" foam.  The foam just floats. 

I used the Pink Sill Frame foam to fill the Fastrack cavities.

Once everything is ballasted it is fairly quiet.  I also used the black skirt wrapping which keeps the noise down.

Matt

Foam shrinks that much?  I haven't seen that with our modular club, that's the first time I heard of that!

It appears that properly manufactured Polystyrene foam shouldn't shrink much once it is shipped from the factory.

Shrinkage Behavior of Polystyrene-based Foam Molded Parts Depending on Volatile Matter Content and Other Factors

Some two rail builders have used 2" foam set into horizontally mounted steel stud frames for around the wall layout.  Article in 48/' awhile ago.

Code does not allow for foam to be use in residential application unless it is covered with a minimum of 1/2" drywall.  This code is not well known nor enforced except in medical environments.

How loud (relative to other construction methods) would a 2" foam base be for a layout which will not be using ballast? I'm going to use Atlas 3 rail exclusively. This seems like a reasonable solution for a 3 month layout which can be broken down quickly and without tools. If I used a very thin 1/4" plywood under the foam, would that help reduce the noise? Is two inches better than one with the thin plywood on a thin frame? The other thought I had was to use 3/4" iron pipe as legs attached directly to the foam as I have no section bigger than 4x4 to worry about sagging or shifting. I can fasten the table to the wall too. Goal being fast in and fast out with little mess so I can focus on the actual layout, not on the structures.

I just moved, and now have room to build a nice layout for our Christmas village. The room itself will absorb some noise due to thick carpet and lots of furniture. But it has to be temporary. However, from a comment above, it feels like foam might turn into a snare drum. Benefits may outweigh the noise deficiencies though.

My one experience with 2" foam with track directly on it was fairly loud.  The foam is quite rigid and performs like a drumhead.  I have to say, my plywood and Homasote deck is very quiet.

The two things that kill noise are (a) isolation and (b) density. Contrary to what you might think, lightweight materials like rigid foam are very poor choices for this purpose, because they accomplish neither.  The reason Homasote works so well is because it is quite dense.

2 inches!  That is a lot of shrinkage ( wait let me find my engineering hat; no not the red one!)

Shrinkage/expansion  equals  alpha delta T; s=a Dt  where a is coeff of thermal expansion for Styrofoam and Dt is the change in temperature the foam experiences.

For Foam a=0.000035in./(in.)(F); so for 2" of shrinkage the Dt is 2/.000035 = 57,142 degrees F.   

The temperature on the surface of the sun 10,000 F; so for a 2" shrinkage the change in temperature of the Foam was almost 6 times the surface of the sun.

OK someone else have an engineering hat??

Menards has homasote so I may just do the 1" foam and homasote on top of a temporary set of legs. I'll be doing some prototype work shortly to figure out what works best I suppose.

Thanks

@PeteB posted:

Menards has homasote so I may just do the 1" foam and homasote on top of a temporary set of legs. I'll be doing some prototype work shortly to figure out what works best I suppose.

Thanks

Sounds like a good plan. If you add a framework of 1x4 joists 18" (or less) on centers, I think you will find it a fine permanent solution--it will easily support your weight if needed.

Yeah, I'm trying to avoid a permanent solution though. I'd prefer something that can be put together in sections and stored, but if not, something cheap so when I disassemble, I'm not paying hundreds to put it back together next year. Hence the foam on simple legs. Easy up, easy down, and replaceable.

I have a new shed as part of my new house though, so I may have a way to store a homasote and frame concoction if I can make it light enough I suppose.

@PeteB posted:

Menards has homasote so I may just do the 1" foam and homasote on top of a temporary set of legs. I'll be doing some prototype work shortly to figure out what works best I suppose.

Why are you hung up on foam?  1/2" plywood and 1/2" Homasote is a far better solution.

@Dillonm posted:

I Built a 6X12 modular frame and use 2" foam.  The foam just floats.

I used the Pink Sill Frame foam to fill the Fastrack cavities.

Once everything is ballasted it is fairly quiet.  I also used the black skirt wrapping which keeps the noise down.

Matt

This seems to make sense because sheet foam might reflect sound and can make things more noisy because of this.  However, by covering it with ballast and scenic material you are reducing the reflective sound.  The same thing seems to occur when you add scenic material to plywood, except plywood is noisier because its hard surface reflects a lot more sound; whereas foam is softer and it absorbs sound.  Skirting below muffles any noise that goes through the surface and is under the table.  I suspect that is why it is fairly quiet as you say.

@PeteB posted:

How loud (relative to other construction methods) would a 2" foam base be for a layout which will not be using ballast? I'm going to use Atlas 3 rail exclusively. This seems like a reasonable solution for a 3 month layout which can be broken down quickly and without tools. If I used a very thin 1/4" plywood under the foam, would that help reduce the noise? Is two inches better than one with the thin plywood on a thin frame? The other thought I had was to use 3/4" iron pipe as legs attached directly to the foam as I have no section bigger than 4x4 to worry about sagging or shifting. I can fasten the table to the wall too. Goal being fast in and fast out with little mess so I can focus on the actual layout, not on the structures.

I just moved, and now have room to build a nice layout for our Christmas village. The room itself will absorb some noise due to thick carpet and lots of furniture. But it has to be temporary. However, from a comment above, it feels like foam might turn into a snare drum. Benefits may outweigh the noise deficiencies though.

My friend has a 4&16 layout of 2" foam boards on which the track is laid on top of cork roadbed.  The foam boards are glued with Elmers Wood glue directly to his Mianne benchwork.  He used the green foam and it's been up for several years with no shrinkage.  To my ears it's essentially the same volume to run trains as running them on plywood.  Of course, I'm used to the noise of running trains on a 135'x30' layout and my favorite music genre is metal so I may be biased.   Your mileage may vary.

Personally, I just finished the framework for my new layout which is essentially 4'x20' on 3 of 4 sides going around the room (the 4th is mostly 1' wide).   It will be covered by 2" thick foam boards with the track mounted on cork roadbed.   At $24 per 4'x8' sheet for foam vs $56 for a 4'x8' sheet of plywood it was a no-brainer considering how much easier scenery will be with foam instead of plywood along with the fact I will never need to put my weight on it.   In my case foam is better than plywood but if my layout was of a different design I wouldn't use it.  It all depends on the individual and the situation.

-Greg

A further advantage of a plywood base is being able, anywhere under the table, to screw in terminal strips needed for accessories or transitions between bus and feeders. Most often, the terminal strips are located on the side of the 2 x 4's but sometimes that is not always possible. For example, my switch light-stands, track signals, and street lamps use short, thin wires that I terminate on strips screwed into the plywood.

@PeteB posted:

Yeah, I'm trying to avoid a permanent solution though. I'd prefer something that can be put together in sections and stored, but if not, something cheap so when I disassemble, I'm not paying hundreds to put it back together next year. Hence the foam on simple legs. Easy up, easy down, and replaceable.

I have a new shed as part of my new house though, so I may have a way to store a homasote and frame concoction if I can make it light enough I suppose.

I understand what you're after but also consider what handling and storage will do to the foam. It doesn't take much at all to dent, scratch, tear, etc. You'd probably need some kind of crate to keep it nice between setups. Even homosote may get damaged moving things around. (It isn't that hard to patch homosote if it hasn't been glued down. And homosote isn't that light. Anyway, you don't want to be repairing things each time you setup. I'll suggest 1/4" plywood or hardboard over a 1x2 frame. It could be built in sections that lock together. If you attach handles in the middle to the underside of the frame they could be carried easily by one person.

Plywood usually comes in large, cumbersome sheets that are difficult to deal with but there are tricks to it. I handle plywood by myself all the time. Well, except for the guys who help load my truck at the lumber store. It's all about leverage and balance. I can't always back my truck down to my basement shop doors but still need to move sheets from the driveway to the shop. My days of carrying a sheet on my arm by myself are long gone so I picked up a simple thing drywall hangers use but also works great for plywood sheets. This one has pneumatic tires to handle going through the yard. Probably not difficult to make something like it. Lay the panel on it's side, relatively balanced, and walk away with it.

I like the discussion, thank you. I think after all of this, I plan to simply build a very thin and light bench using 1/4" or thinner plywood and pine 1x2's to frame it with a thin cork overlay on top (painted white, decent snow effect actually). Legs will be made out of cast iron pipe with fittings so I can attach and detach them easily. Atlas 3 rail simply screwed to the plywood over the cork. I'm going through my shed now to clean it out and build a place to put the bench sections when not in use. None of the sections will be more than 4x4, which helps this effort.

I think the tradeoff for easy deconstruction is it's not going to deaden a lot of noise. Honestly, the train itself doesn't run a LOT when up. However, in the past, this Christmas layout has been MUCH smaller and more done to match the village around it, it wasn't as much fun. This layout will be much bigger, and the curves better able to handle the engines. So I know I will want to run it more unless I get noise complaints from the SO. Whatever happens with this build will feedback any improvements I want to make for the next iteration.

If it turns out noisy, you can attach homosote on top or underneath between the framing. Also, the auto parts stores usually have some self-sticking damping mats that could be stuck underneath.

You might want to consider 1/2" plywood instead of 1/4".  1/4" is very thin and will not span very far without reinforcement.  Also, you might also want to consider cutting Homasote for your road bed.  This will help a lot with sound.  That's what I use and it has serve me well.

There has been a lot written about sound on this forum.  You can search it.  A lof it is anecdotal based on personal perceptions.  I'm in the building materials business and I've learned, unless material is tested for sound, we can't say conclusively.  Homasote is sound tested because that is it's main purpose,  just as rock wool insulation is used and tested for sound for wall insulation.

I contacted Owens Corning last year and asked them the question regarding using foam for model railroad layouts for sound and this was their response:

"Unfortunately, the Foamular products are not tested for sound absorption. While it will assist with some sound transmission, it may not be the ideal product for this."

I use it because you can carve it and it seems to assist with sound, but I have 1/2" plywood as my base and Homasote as my roadbed on top of it.

Mike

Wow, truly amazing.

I used 1.5 inch thick foam core (the kind that is foiled on both sides - can't seem to find the pink or blue foam here (SF bay area) anymore) on my "temporary" layout, where the biggest span is a roughly 2' x 4' rectangle.  I run S-gauge (Flyer, etc.) so I suppose the engines are a bit lighter in weight.  I have NO sound issues.  Since this is a "temporary" layout (lessee, its been up about 5 years...), I haven't done anything fancy, though the top of the foam core is covered with a brown felt-like fabric (mostly so the shiny Al foil covering is covered up).  Why foam?  First, its a hellavalot easier to handle and to cut, which can be done in situ without filling the room with sawdust (I sharpened the edge of a 3" putty knife - drawn along a metal straight edge, works like a champ).  Second, its very easy to run wires, etc. through (sharp nail, drill bit, etc.  Since the foam table is butted up against two walls in a room in my house, I'm not concerned about the foam damaging the wall (unlike plywood).  And fourth, it will be 'easy' to take apart when I get to move it to a bigger room (da boss and I are still in the negotiating stage...).

Avanti (Pete), boy those recessed Lionel accessory bases look great! I might steal that idea.

Don

One thing I should come clean about is that the platform top is not just 2 inch foam. I made a "layer cake" of 3/8 inch plywood, 2 inch foam, another 3/8 inch plywood and another 2 inch foam. See pic. So my platform is very dense and pretty sound dead. I have no noise problem.

The last pic shows a removable foam base and future mountain side where my Sierrawest sawmill will eventually reside. This base covers some track and has to be removable for access.

Don

I hate going up against the gun runner...but foam vs plywood and homasote is a done deal. Foam costs less, is FAR easier to handle and is insanely easier to make changes to. If I was building a MUSEUM layout to be up for the next 25 years, I'd use plywood and homasote. But since this is in my basement and will probably not be up longer than 10 years, I think I'll go with the foam solution--less expensive, with much faster build time and far easier handling.

I built my last layout on plywood and homasote. To this day I blame my respiratory allergies on the dust I inhaled from cutting and working with that **** homasote. Never again.

Don

You can cut Homasote indoors essentially dust free or you can cut Homasote indoors in a cloud of dust.   Your choice.

I have been cutting Homasote indoors for clients for a very long time.  It can be done safely and cleanly.

@Don Merz 070317 posted:

Avanti (Pete), boy those recessed Lionel accessory bases look great! I might steal that idea.

Don

I have 1" green/blue foam sheets over 1/2" plywood with Fastrack laid on top of the foam.

Foam makes it easy to recess the bases of whatever you want - as an example, here is a Z-Stuff crossing gate with the base recessed, but the pole and cabinet at ground level.

Since I was a beneficiary of Tom's expertise at cutting Homasote indoors, I can attest to the fact there was very little dust that escaped the vacuum, no mess at all.  I'm not sure I see how foam is "insanely easier" to make changes to, it seems to me it would be a similar process of cutting and fitting. Any straight cuts in Homasote can be done with a utility knife, no mess at all.  I was sure that routing the edges of all my curves would be super messy with the Homasote, but again having a vacuum right there sucking up most of the dust really made a huge difference.

FWIW, I've worked with 2" foam, and cutting that with a jigsaw creates a lot of mess, so it's not like it's not going to require cleanup.

The main reasons for going with Homasote was it's sound deadening qualities, in that regard it far exceeds the construction foam.  Since that was the primary reason for putting a layer on the plywood in the first place, the decision was an easy one for me.

Tom,

How do you cut Homasote with minimum mess?  Vacuum?  Knife?  Do you use Homasote as a complete table top on top of plywood instead of road bed?

Cutting straits for me has been a minimal mess using a circular saw.  However, when I've cut my 0-42 curves I've used a jig I made and a router in order to get a consistent 15 degree beveled edge.  This creates a mess, but I like my clean curves using this method.  I'm also able to use 1/2" foam as filler for road bed below Ross switches or non-42 curve sections.

Mike