I’m working on a highway overpass that will have a rather steep raised approach. It also curves. Here’s what it looks like now with the overpass and no approach. I’ll likely have to make a cinder block retaining wall on the motel side of the approach hill:
The layout is pretty old as it dates back to 1973. However I’ve been updating a few areas lately. Back when it was first built, my my dad made the mountains and scenery with Durhams Water Putty on top of a newspaper and cloth frame.
I could do the same process for the overpass approach, but I think foam might be a little easier. I would completely cover the foam with joint compound or Spackle…or something similar. And I’ll paint and landscape it as well. The foam will basically be the frame work/base for the approach. And I’ll use thin styrene for the road section.
Never having used foam for modeling purposes I have a few questions.
My questions are:
What type of foam should be used for model railroad purposes? Thickness?
Where can you purchase this foam?
How much foam do you think I’ll need for this approach?
What should I use to “sculpt” the foam?
Should I use Durhams Water Putty instead of foam to match the other scenery?
Dan has answered as I would. One thing, is it possible to shift the overpass towards the right closer to the existing hillside? This would allow you greater room for the ramp and will blend into the existing elevation, you can decide by mock ups the exact placement and slope of the approach. The retaining wall on the hotel side still would work and look good.
MATT ,I note you’re in Anaheim,ca finding pink or blue is going to be tough and expensive in so cal . BUT there is a Home depot (the only one in S.C.) that has the pink in 2" & 1/2" thick ,2" x4x8 well hit you about 28-38 American $ ,sorry just cant remember price for shure . the only store: is on tustin blvd half way between 22 & 91 frwys, If you’re in Anaheim you know where I’m talking here .
I just drove down and picked up a sheet there last month… PS make sure you ask for “PINK extruded foam board”…Jerry
Thanks for the tip Jerry. Maybe that’s why I haven’t seen the typical layout looking foam around here.
I’ll check out the Home Dept you mention. I think the one you’re mentioning was the old K-Mart on Tustin and Taft. It’s really close to where I live (Anaheim Hills).
I would use 3/4" foam to create the actual roadbed for the approach ramp. I would then create some support pieces out of foam to support the roadbed. Then for the hillside on either side I would use the cardboard strip lattice and plaster cloth method to create the terrain. This would give you a smooth base for the road versus stacking foam and trying to carve the roads path.
Be aware than many Home Depot locations in mild-winter areas will tell you they have the extruded foam in stock because it looks that way on the computer. But often it’s not really there. Ask someone to go back to look at it to confirm before you drive. Or try one of the more consistent So Cal sources on this page
I’m going against the grain and saying stick with plaster.
This scene has a certain charm to it, and the fact that it’s lasted since 1973 means there might be a little nastalgia going on here. Try to “compliment” the scene with your modifications, not enhance it.
Wouldn’t mind seeing a few more picks of the layout too. [;)]
I probably will do a top coat of plaster to match the surrounding terrain look. Although I’ll use Durhams Water Putty and not true plaster. It’s just what to put under it to keep the shape/form that I’m debating on.
You want “extruded foam board”. Comes in blue and pink, either color works just fine. Comes one and two inches thick. Two inch thick will make your off ramp with fewer joints, but the stuff glues together easily, and one inch will work too. Avoid “bead board” a white crumbly foam often used to package electronics equipment, and sold in sheets. Beadboard makes a dreadful mess when cut, and lacks strength.
I get my foamboard from the local lumber yard (Varney and Smith). The big boxes (Home Depot and Lowes) will have it. Scraps are often lying around construction sites and can be had for the asking.
I’d guesstimate that a piece of two inch foamboard about 2 ft by 4 ft would be plenty. If you buy new, a 4 by 8 sheet may be all they have. Costs like $20 a sheet. You can get a 4 by 8 sheet home tied to the roof of your car, just keep your speed down to avoid it blowing away.
Foamboard cuts with saws, steak knives, surform rasps, and hot wire cutters. The plastic sawdust is messy and hard to clean up, even with a shop vac. Cut outdoors, as much as you can. It’s not as messy as mixing plaster though.
Matching the existing scenery is really a matter of matching the color and texture of the ground cover rather than whether you use water putty or foam. My layout is all foam and I just painted the foam earth color and sprinked died sawdust into the wet paint for a green grass ground cover. Come to think of it, many state highway departments plant highway embankments with grass to prevent erosion. If you do that, then your new offramp doesn’t have to match your existing brown sandy desert look. Or, you may decide to “refresh” (repaint) all your ground cover, in which case everything will match exactly. You may come to this option when you find that you cannot buy, mix, or make ground cover
