# Question on foam baseboard and installing tortoise switches



## Burbs (Mar 28, 2014)

I’m in the planning stages for my benchwork for my HO layout and I’m leaning towards using 2” thick foam insulation board instead of plywood. The issue I’m seeing here locally that finding 2” foam board is hard but finding 1.5” seems a bit easier. My benchwork will have center supports so I’m not worried about the baseboard not being supported enough.

I do have two questions however:

If I can‘t find 2” XPS boards would it be ok to use 1.5” with .5” on top to equate 2”? _(I realize I’ll have to glue the .5” on top but that’s not an issue)_
I did Google “installing a tortoise switch to foam board“ and it appears they recommend either glueing a 4” piece of 1/2” plywood to the bottom of the foam and then installing the switch to that. Or I saw someone installing it flush from the bottom on piece of perfboard. What have some of you done? What would be the recommended way of doing it? 
Thanks,

Burbs


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## Lemonhawk (Sep 24, 2013)

We are talking about extruded foam board, not the Styrofoam stuff made of little pebbles of foam, right? You might check actual lumber companies, here in Florida Lowes and HD do not carry anything thicker than 1".

As far as mounting stuff on the bottom like stall motors for the turnouts, its probably easiest to use some sort of wood pad, not sure you wound need 1/2" I thick, 1/4" would be fine, You can always use a plastic expanding fastener, or use a blind nut that you tap into the other side of the ply and the use machine screws.


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## Stumpy (Mar 19, 2013)

1. Unless you need to dig into the base board more than 1.5", then just use the 1.5".
2. This is what I'll be doing on the next layout. Gluing a 1/4" thick wood pad wherever I need to mount something to the bottom that requires screws.


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## cv_acr (Oct 28, 2011)

Burbs said:


> I’m in the planning stages for my benchwork for my HO layout and I’m leaning towards using 2” thick foam insulation board instead of plywood. The issue I’m seeing here locally that finding 2” foam board is hard but finding 1.5” seems a bit easier. My benchwork will have center supports so I’m not worried about the baseboard not being supported enough.
> 
> I do have two questions however:
> 
> ...


1. Just use the 1.5". Should work just fine. Stack and glue more layers only if you need it for scenery formation depth/height in a particular area.

2. Since you can't screw anything into foam, glueing some sort of mounting surface like thin plywood or hardboard to the bottom of the foam (or attached to the bracing that holds up the layout) will be necessary to attach the switch motor to.


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## DonR (Oct 18, 2012)

Haven't checked the prices but I'm told that plywood is
now very expensive.

However, if it is at all affordable, I'd go with a thin, 1/4'" or so plywood
for your benchwork top. It gives you a solid base that you
can screw into for your turnout motors et al. I used 1/4"
paper covered foam from Walmart or Michael's crafts
section over that. It provides a smooth base for tracks
and scenery. This would save you the extra work
needed to make your turnout motors stable and
secure.

Don


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## Burbs (Mar 28, 2014)

My local Home Depot has 1.5” thick Ownings Corning board albeit low inventory, definitely not white styrofoam stuff. Plywood is definitely more expensive now due to the supply chain so I’m 99.9% decided on foam now.

I’m building my modules in 2x8 and was hoping to find 2x8 foam board but the only place I’ve seen that is online and they want $56.00 per sheet plus shipping. 

Anyone have any tips on how to cut the 4x8 foam boards cleanly? At $27 a board and low inventory, I really want to get it right the first time.


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## Burbs (Mar 28, 2014)

Ended up buying a hot iron knife from Northern Tool today. Haven’t used it yet but looks relatively simple.


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## Lemonhawk (Sep 24, 2013)

I prefer Lauan plywood, it's about 3/8" thick and is much better to screw into than 1/4" ply which is very coarse. besides the thick exuded foam, I also use that fan-folded extruded 1/4" insulation that is used for behind siding (I think). Its around $50 for the pack, but they usually have some damaged ones that will be much cheaper! I use it as a base for putting the road bed on to help sound deadening and to make a backing for walls and cliffs. You can even build inclines with the stuff and stone block walls with it. One pack will give you enough for a long time! Glue it with Liquid Nails for projects.


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