Structure Base

[TomPM]

I am getting ready to begin constructing a base for the HO Scale Walthers Northern Light & Power kit that I just finished building. I decided to build a base for it now because the layout will not be ready for it until after I complete a major rebuilding.

What material should I use?

Someone had suggested that I can use foam board (the type that would be used for a poster board display). I am concerned that it might warp when I glue the turf to it.

 

[tomfassett]

Foam board is pretty rugged. I know a lot of architects use it for its light weight and stiffness. I would guess that unless you are planning a 4' X 4' structure of larger, the foam board should be fine. If in doubt, clamp the foam board to a piece of plywood while working on it. After everything dries completely, you can remove the plywood and the structure should stay perfectly flat. You could do this by cutting the foam board larger than the final size desired and attaching to a piece of plywood by screwing small strips of wood or metal around the outside of the model (in the area to be removed later), through the foam board and into the plywood. This frame will keep the foam board from warping. See the attached graphic.

Tom F

 

[NYCentral]

I use foam board with great success. I have also used very heavy card stock both purchased at a art supply center. I like the card stock when I don't want the structure raised up any. I do seal the card stock with a spray sealer (I use Duncan matt sealer but I think you could use any sealer). The card stock I have purchased is very stiff poster board in 2'X3' sheets (I think).

With the foam board I do not use any sealer, just start glueing down scenic materials. I like the bases because you can scenic right up to the structure and you can easily work on them while at your bench as opposed to leaning over the layout and doing the work.

 

[Casey Feedwater]

I've also used foam-board (around here it's called foam-core) with great success. I "laminate" it to my plywood sub with Elmer's yellow carpenter's glue. I've never had any trouble with warpage when painting and doing scenery over it.

I did use a sheet of it once for a freestanding backdrop (to be used with a diorama). I painted the sky and clouds on it in my usual manner. By the next morning, it had curled into a near quarter-circle. That was enough to convince me to keep using a plywood backing as I had been doing on my layout.

Recently, however, I've switched to fan-folded pink foam. I can get a bundle of 2' X 4' X 1/4" foam for $23 at Home Depot. Each bundle contains 25 sheets. It's as strong as the foam-core when glued to plywood, it's easier to cut than foam-core, and it's cheaper to buy that way. Plus, I can cut and stack the sheets to varying heights for rough scenic contours.

 

[Vic]

Hey Tom, If your layout is to be covered with a material such as Homasote, Foam Board and etc. make the base for your structure the same thickness as the material that the layout will be covered with. That way when you go to install the structure all you have to do is trace around its base, cut out a hole in the covering and drop the structure and base in and scenery around it. It won't look like its sitting on a mound of dirt!

 

[Vic]

Note For Casey

Hey Casey, Did you use latex paint on the foamcore board? If you did that's why it curled. The outside layer is actually a hard paper board and absorbs water from the latex paint and then shrinks. At one time I worked for a screen printing company. We made interior signs and trade show displays from foamcore. We always overcoated them with enamel paint for the background color and then printed them with enamel ink so they wouldn't curl up. We used to make them up to 4'X8' with no curling problem. Just thought I'd pass this along in case you want to try again

 

[NYCentral]

The foam core I have has a plastic cover not paper, or it is coated with a plastic like substance (not really sure what it is) I have used latex paint on it without any problems before. I guess it matters what you purchase.

 

[Casey Feedwater]

Re: Note For Casey

Originally posted by Vic
Hey Casey, Did you use latex paint on the foamcore board? If you did that's why it curled. The outside layer is actually a hard paper board and absorbs water from the latex paint and then shrinks.

Hi, Vic. Yeah, it was latex paint. The funny thing is, the foamcore I buy is like what Phil described: it has a plastic-appearing surface. The fact that it curled, though, pretty well says that the surface isn't plastic. It may be a "glossy" hardboard surface and absorbs the paint as you're suggesting.

I wonder if I paint the backside if it would straighten out the curl....

 

[TomPM]

Thanks for the suggestions.

I tried an experiment with the foam board/foam core. First I painted it earth color. No problems encountered. I then glued down some WS turf on it using my usual 50-50 solution of white glue and water. When it dried the base warped.

I guess I will try the foam insulation or use one of the ways to brace the foam board/foam core suggested.

 

[tomfassett]

Vic's right. The stuff looks slick but it is really just paper. Tear some off and you will see that it is flat (surface finish wise) on the other side. It has a surface texture similar to slick photo paper. Another idea (which I have not tried) would be to seal the stuff before using it. Spray it down with a good flat finish (like art sealer) and then add the scenery. I used to use a lot of art matte spray and you could spill coffee on it and wipe it right off with no stain. I would assume this shows that the paper is pretty well sealed. I think I have some of this stuff left in the home office somewhere. I'll try it out on some foam board and let you know what it does...

One more thing to keep in mind, Tom. Glue shrinks as it cures. Watered down glue shrinks even more. If you secure the foam so that the glue is forced to "migrate" along the surface as it shrinks, it will be less apt to bring the board along for the ride. I think this problem would be evident even on sealed foam board (though not as pronounced).

Tom F

 

[Gary Pfeil]

Here is a link to a page describing using foamcore as a core for structures. It also talks about the kinds of foamcore available. http://www.horailroad.com/clinic2/cl2_017.htm

Gary

 

[Drew1125]

Just An Idea

I was at Home Depot yesterday, & saw some of those acoustic ceiling tiles...those little 1/2 in. thick, 2x4 sheets that fit into those "dropped ceiling" frameworks...
I've read about people using these for various scenic purposes, though I've never tried it...
I've always thought that you could cut them to fit a space on your layout, & then build an entire scene, structure, town, etc, at the workbench, & then drop it into the space. I think this would work best on an open-frame type of benchwork.
Anybody here tried this?

 

[Casey Feedwater]

Charlie, I've not tried that myself, but about 20 years ago there was an article in RMC about that very idea. As I remember it, the author described how he constructed "plug-in" scenes on a standard-sized diorama base. All scenes and trackwork were interchangeable, so he could alter the appearance of his layout at will. I remember one set of photos showed his layout as a steam-era setup and the next set showed it as a modern diesel-era setup with completely different industries.

 

[NYCentral]

Originally posted by tomfassett
Vic's right. The stuff looks slick but it is really just paper. Tear some off and you will see that it is flat (surface finish wise) on the other side. It has a surface texture similar to slick photo paper. Another idea (which I have not tried) would be to seal the stuff before using it. Spray it down with a good flat finish (like art sealer) and then add the scenery. I used to use a lot of art matte spray and you could spill coffee on it and wipe it right off with no stain. I would assume this shows that the paper is pretty well sealed. I think I have some of this stuff left in the home office somewhere. I'll try it out on some foam board and let you know what it does...

One more thing to keep in mind, Tom. Glue shrinks as it cures. Watered down glue shrinks even more. If you secure the foam so that the glue is forced to "migrate" along the surface as it shrinks, it will be less apt to bring the board along for the ride. I think this problem would be evident even on sealed foam board (though not as pronounced).

Tom F

I looked at the stuff I have and it is all plastic, I even tried to rip it but couldn't without a knife. I don't think it is the same as the stuff the rest of you are using and talking about. I have about 6 sheets left that I purchased a few years ago, but none of them have a brand name on them.

 

[Vic]

Foamcore

Not impossible...maybe there's a new version of the stuff! All that I ever delt with was surfaced with what is called coated board.

 

[tomfassett]

Hey Phil, I think you got your hands on that missing batch of material NASA uses to make space shuttle tiles. They want it back...

The same would apply as far as securing the board while the glue dries to prevent it from warping as the glue shrinks.
A couple of years ago, I got my hands on some scrap plastic at a plastic and plexi distributor. It was in their "odds and ends" bin for $1.00 a linear foot (16" wide, 1/4" thick). The stuff feels like extremely lightweight tile and cuts like fiberglass. A 16" X 12" piece must weigh in at under 10 ounces. The stuff is so rigid and strong that I can stand on a 16" wide piece spanning two blocks. Keep in mind that I am 6' 4" and 270 pounds and you can appreciate the strength of this stuff. It has some kind of fiber in it (like carbon). Now, I am not suggesting that everyone should comb the countryside looking for this particular stuff, but I mention it to illustrate that there are alternatives to what we normally see in the lumber department at Home Depot or the craft department at an art store. I run into a lot of various materials in my work and some of the stuff is amazing (I know, I often have to drill or cut through it). One thing that comes to mind is a material called FRP (Fire Resistant Panel) used in restaurant kitchens and commercial bathrooms. This stuff is brutal to hand cut and not the least bit flexible. I don't think you could appreciably warp a 12" X 12" panel of the stuff if you used an entire bottle of glue and REAL masonry for the model bricks... I'm sure it can be purchased at most contractor building supplies. I have also seen fiberglass panels that are extremely lightweight and rigid as well. Even Plexiglas is more rigid that sealed foam board, so are a lot of the acrylic panels.
In most larger cities, there are plastic resellers that carry a wide range of stuff, and most have a "scrap bin" where you can get small pieces of stuff for less than 10 cents on the dollar. I also see a lot of scrap FRP in the big construction bins at restaurants and hotels that are under construction or being remodeled. It is usually best to ask before "dumpster diving," (for liability reasons) but I have found most contractors to be very helpful if you make a point of asking first and not inconveniencing them. A box of Krispy Kreme donuts or a couple cups of Starbucks coffee doesn't hurt either...

Tom F

 

[Lackawanna Jim]

Tom;

Someone (Vic?) hit on the solution; simply pre-paint both sides with any latex paint. That will help the curling issue, at least with paper-backed foam. I haven't seen the plastic-backed foam in years (like, 20 years); one neat thing about the plastic-backed stuff was that you could very easily remove one of the plastic sheets, exposing the foam layer inside... Another tip; if you can get some Bestine Rubber Cement Thinner, you can soak the paper and carefully peel it off the foam, again exposing the foam inside, for whatever reasons you would like (carving, curving, etc...).

Jim

 

[Vic]

Hi Jim, Nope it wern't Vic that said paint it with latex paint Vic said paint it with enamel paint so's it don't warp up! Water in the latex paint is what makes it warp. Ain't no problem though....just getting us all back on the same page again LOL

 

[shamus]

Hi Tom,
I always use a card base cutting the edge at 45 degree angle to blend it to the baseboards, then simply had grass/weeds later. Here's a loco shed before it was bedded in.
shamus