# What type of foam to use.



## Geno the Viking

What is the best type or brand of insulation foam sheet to use as a base or for scenery. There is some variety out there but I haven't heard this discussed. Ready to buy. Thanks


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## flyboy2610

Do NOT use white Styrofoam! Those little balls will get all over everywhere and you will never get them all cleaned up!
As for extruded foam, there really isn't much difference in brands. Whatever your local home center or hardware store sells should work just fine. I use Owens-Corning from Home Depot, but whatever brand your local store sells will work fine.
For gluing foam to foam (not roadbed to foam or track to foam, but foam to foam only) the best thing I've ever used is Glidden Gripper primer paint. A very thin layer between two layers of foam will ensure that they never come apart again!


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## Fire21

You want polystyrene foam board. One brand is as good as any other, they just come in various colors depending on the manufacturer. They come in different thicknesses...1/2", 1", and 2" are the ones I know of. Some places only sell 1", such as warmer areas needing less insulation, but you can glue sheets together to get any thickness you want. If gluing, but sure to use proper adhesive, as some will melt the foam. I've used PyroLine 300 foamboard adhesive.

Good Luck! :smilie_daumenpos:


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## traction fan

*Extruded foam*



Geno the Viking said:


> What is the best type or brand of insulation foam sheet to use as a base or for scenery. There is some variety out there but I haven't heard this discussed. Ready to buy. Thanks


Geno;

The foam of choice is called "Extruded foam insulation board."
As the other have said, it comes in several brands, and the brands are equal in quality. Dow Chemical makes their foam in blue. Owens Corning sells pink foam, and I've heard of a third color green, but I don't know which company makes it.
Home Depot or Lowes should have this type of foam. They also sell white "beadboard" Styrofoam. This is much softer and when cut with a saw, emits clouds of super light beads all over. A shop vac will clean them up, but they are a major pain to catch if there is any airflow, let alone a wind. This white foam is not recommended as a scenery base. Use the blue, pink, or green types.

good luck;

Traction Fan:smilie_daumenpos:


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## Geno the Viking

Ok guys thanks so much for the fast answers. I bought some white foam board as that was all they had in stock. I'm taking it back for the good stuff.


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## CTValleyRR

Geno the Viking said:


> Ok guys thanks so much for the fast answers. I bought some white foam board as that was all they had in stock. I'm taking it back for the good stuff.


Just have a look at the foam. If it looks like a bunch of spheres smushed together, that's not what you want. If it has a smooth surface, and the cut edge looks solid, with only very small pores in it, that's the stuff you want. Pink, blue, and green are the normal colors. My local lumberyard calls them "Dow board" (even if it's really another brand).


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## Chiefmcfuz

https://www.rubberflooringinc....e/foam/58-soft-turf-tiles.html

A little expensive but really keeps the noise down and comes in different colors.


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## CTValleyRR

Chiefmcfuz said:


> https://www.rubberflooringinc....e/foam/58-soft-turf-tiles.html
> 
> A little expensive but really keeps the noise down and comes in different colors.


For roadbed, perhaps, but we're talking about the actual layout surface itself, using extruded foam insulating boards.


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## Chiefmcfuz

Ah ok.


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## ErnestHouse

This was a concise and valuable thread when researching an approach for my new layout but the terminology on foam left me unclear. Here is the deal, there are two types of polystyrene commonly found at your home improvement store. One is good. One is bad.

Good: Extruded Polystyrene aka *XPS* 
Bad: Expanded Polystyrene aka *EPS*. You might be fooled into thinking the "E" in EPS is "Extruded" but you would be wrong. EPS is what some call styrofoam or bead board. This is the stuff that breaks up into thousands of white static filled crumbs of styrofoam.

To recap, for a layout substrate, you want Extruded Polystyrene (Pink, Green, Blue).

As far as South Florida goes, you will only find 1" or less in the big box stores. But once I knew what to search on, I found a Supply house that had thicker. Forget about finding Homosote. YMMV


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## Riggzie

wow so now im not only using this stuff for Halloween decorations next year, I am going to use it for my train... eventually...


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## cole226

*foam board*

here's what I use from Lowes


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## Riggzie

cole226 said:


> here's what I use from Lowes
> 
> View attachment 520722



can this be used on the entire layout, even under the tracks? I saw the thread about the track noise and how to lower.. so will need to look at that again...


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## ErnestHouse

Riggzie said:


> can this be used on the entire layout, even under the tracks? I saw the thread about the track noise and how to lower.. so will need to look at that again...


The layers from top to bottom are:

Track
Trackbed (cork or squishy foam)
Extruded Polystyrene
Plywood
Benchwork

Rubberized adhesive between plywood and benchwork optional. The key to lowering noise from XPS layer is the trackbed. I found the attached article in another thread. If you use track that has the ballast on it, you still need to separate it from the XPS with a layer of cork or something to stop the noise from being transmitted to the XPS.


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## CTValleyRR

ErnestHouse said:


> The layers from top to bottom are:
> 
> Track
> Trackbed (cork or squishy foam)
> Extruded Polystyrene
> Plywood
> Benchwork
> 
> Rubberized adhesive between plywood and benchwork optional. The key to lowering noise from XPS layer is the trackbed. I found the attached article in another thread. If you use track that has the ballast on it, you still need to separate it from the XPS with a layer of cork or something to stop the noise from being transmitted to the XPS.


You don't even need the plywood. If your foam is supported on 2' centers, it will be plenty sturdy.


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## Gramps

I'm jumping in with additional questions: What is the minimum thickness foamboard to use? Do you need a special tool to cut it?


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## ErnestHouse

@Gramps, I am building a new layout and researched all this more than person should.

IMHO, the thickness of the foamboard depends on your goals for using foamboard. One reason to use 2" because it is strong enough that you don't need plywood. Another is because you want that depth to carve below surface features such as canyons or rivers in your layout.

It's a misconception that Extruded Polystyrene Foamboard is a sound deadening layer. It is not. Actually it's the opposite. So in using XPS of any thickness, it's key to factor in a roadbed of some kind if you want to address track sound issues.

I chose 1/4" luan plywood over my benchwook glued and screwed with silicone adhesive and sheetrock screws. I'm then using 1" XPS for the table top. Then cork for the roadbed.

Two tips if you don't have a truck to buy the XPS:
1) The 4x8 at your supply yard or big box store is scored in the 8' dimension. So you can bend it to snap it off into two pieces that are 2x8 which may fit in your vehicle.
2) HD has 1" in 2'x2' pieces.

As for cutting it, a rough cut can be done with a drywall saw, jig saw, sawzall, circular saw or whatever. But with a straight edge and utility knife, you can score it halfway through and snap it off.


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## CTValleyRR

I cut mine using an aluminum circular saw guide and a mini-hacksaw. Score and snap also works, but sometimes it's tricky to put even pressure along the whole piece so it snaps only where you scored it.

I love the 2x2 pieces for scenery construction, but I'm less fond of them as a base because there are so many joints to deal with.


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## ErnestHouse

QUESTION:
What do you use to fill in the gap for butt joints in the foam?

CUTTING:
For a dust free trimming of excess 1" XPS, I had good results from this Milwaukee 12" knife:
https://www.zoro.com/milwaukee-smooth-insulation-knife-12-in-l-red-48-22-1921/i/G3104389/

It was more difficult cutting the middle of the foam because the foam doesn't fall away like when trimming excess/edges. So it took a couple passes. I'm biting the bullet and getting a pistol hot knife.


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## CTValleyRR

ErnestHouse said:


> QUESTION:
> What do you use to fill in the gap for butt joints in the foam?


Generally, I don't worry about small gaps. The foam rubber roadbed bridges them under the track, and the Sculptamold I use for landscaping fills the others (I always spread ar least a thin layer of Sculptamold over the foam base).

Woodland Scenics foam putty works well, though.


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