Foam board use/types

Model Railroader Layouts and layout building
1

I am building an N scale layout, my first. So, like many, I am inexperienced. I would like to use foam board as suggested by some in 1" or 2" thicknesses to attach to my wooden benchwork (1/4" plywood top).

There are several Lowes and Home Depot’s in the area. Florida is a major housing construction mecca! However, I am finding the selection of foam boards limited. Most of what is out there is the standard kind of white foam that feels very brittle and I know I must avoid the “crumbly” type.

At my local Lowes, I did find Dow Residential R3 blue foam. Unfortunately, it is only 1/2" but I can always glue two boards together. I bought a board to experiment with.

First question: The board has a very thin plastic coating that peels off easily. I tend to think I should peel this off before gluing to my benchwork or the top of my road bed. Has anyone had a similar experience?

Second question: Since these boards are $11 each and I have an L shaped layout, I am going to need at least 2 4x8 sheets to get my base layer and then additional foam for scenery and such. What is the opinion on 1" versus 2"? Should I spring for another $22 and give myself extra potential depth? I don’t plan on any elevations right now but I will have a tunnel and I would like some small bridges.

As a fun thing, I am experiementing with different glues (elmers versus Liquid Nails Projects) for attaching it to the plywood. I am going to do similarly with different glues and caulk for the roadbed and track.

Thanks!

2

Yes, peel the plastic off.
I don’t think I’ve ever seen 1/2" before. Just 1,2 and 3".[%-)] If you plan on cutting ditches/rivers and vallys into it, I would go two layers thick.
[#welcome]

3

Extruded Polystyrene comes in two flavors Blue and Pink. Blue is produced by Dow and Pink is produced by Owens Corning.

Lowes Sells Dow products;

  • Residential sheating available in .5", .75", and 1"
  • Wallmate available in 1.5", and 2"

Home Depot and Menards sell Owens Corning products;

  • Foamular 150 available in .5", 1", 1.5", 2"
  • Foamular 250 available in .75", 1", 1.5", 2"

Ok there are probably other flavors but you get the idea. 2" is the strongest and will support nearly a mans weight at 16" OC, the average man weighing 160-180 lbs. 2" is what I would use as subgrade details are easily carved out of 2" material without cutting completely through.

There are special foam adhesives, straight liquid nails generally eats through foam as its solvent based. There are recipes that are foam safe. Also Expanded Polystyrene, the white beaded stuff isn’t a good bet for structural strength, however its easily carved so makes a good mountain.

Expanded polystyrene can easily be cut with a standard TS and blade, I havn’t seen any blade degradation after using it for foam. There is also surfoam tool, hot wire knife and traditional saw/knife.

Cheers

4

it is hard to find it in florida but if you look at whitecap.com they are local contractor supply here in florida. I think they are in tampa, orlando and i know that there is one on ingram ave in lakeland fl as that s where i got mine.

5

[:-^]

The only use for yellow glue is on the benchwwork, where it is to be absolutly permanent . Use white glue or No more nails as it is water soluable and gives you a forgivness factor.[banghead]

I have used No More Nails for such and also for my roadbed and track and it is easy to use and to re-do if necessary.

Johnboy out…

may the Rails never be Silent.

6

  1. Peel the film off. Not really sure of its function, may be to strengthen the thinner pieces during transport. It is on the thinner pieces, but have never seen it on 1" or 2".

  2. I would go with 2" so you can have a little below grade scenery, especially since you say you’d like some bridges. It is made in 2x8 sheets also, which is more convenient to handle, expecially if you are doing a shelf layout that will not be over 2’ wide. Remember there is virtually no waste as even the smallest pieces can be used to form dirt piles, coal piles and can be attached to the base to create small hills and other variations in land forms.

  3. As for glue. I understand that white or yellow glue will work, but often on large pieces the center never dries as the air cannot get to it. I have had sucess using cheap latex caulk for bonding foam to wood or cork and track to cork. To keep it drying out in the tube between uses I put a long sheetrock screw into the open tip, wrap with several layers of Saran Wrap and secure tightly with a rubber band.

Have fun,

7

Peel the film off.

As for glues, I use Gorilla Glue, it is somewhat forgiving - not much of an instant bond, if you can stand the 3 hr dry time.

I only used 1" and am angry that I did that.[banghead] I wish I would have done 2" it would be more interesting.

Next, invest in a hot foam cutter. I didn’t have one at first, and a regular knife doesn’t work well, especially if you need straight cuts. If you are sculpting a hillside that is a bit rocky, use a regular knife, or use both.

I have a big box with all my waste foam pieces, and am slowly using them up as I go. They make good building supports if no one sees them.

If 4x8 is a too big to carry, and they don’t carry anything smaller, ask if they can cut it for you. That’s what I did. It was at Menard’s, but they were helpful and gave me a knife to do it myself. (They didn’t want to be responsible)

If you buy too much, you can always try using it fake foaming at the mouth.[:D]

MadSinger

8

Peel the film - I think it serves mainly as a vapor barrier when you use the product for what it was intended for. Glue will stick to the film, but then the film will peel off the foam, so much for a secure bond…

I’ve always glued the foam to the wood with yellow glue. On my previous layout I misjudged more than once and banged my head into the bottom of the foam and the yellow glue did not let go at the nearby framework. I’d say it’s plenty strong.

–Randy

9

I’ve had good luck using hot glue on the low temp setting, also liquid nails has a formula for foam but seems to take forever to set when used in laminating layers.

10

I’m currently building my new layout using the Owens Corning 2" pink “Foamular” from Home Depot. It seemed a little pricey ($24-25 for a 4X8 sheet) but I’ve since learned that it was a good choice. I’ve glued it to 1/2" plywood using Loctite Power Grab which doesn’t attack the foam and dries (to the point where you don’t have to worry about its shifting) in just a few minutes. So far, I’m very happy with the combination and would highly recommend it to anyone building a layout.