I am building terrain using historically accurate contour mapping as a guide. To achieve the desired level of accuracy, I am building the terrain in layers, with each layer corresponding to either a 1-foot or 2-foot contour interval. To achieve realism, I must then “smooth out” the spaces between material layers using a shapable medium, like drywall compound or Sculptamold.
To save time and expense, my preference is to build using 2-foot contour layers. At my chosen scale, each layer is 4mm. The most economical material appears to be 4mm Coroplast, a plastic (pvc?) board with a physical structure similar to that of corrugated cardboard. The trick is, I don’t know if drywall compound will stick to it. I will need to transport the diorama multiple times, and I’d hate to see drywall compound delaminate from the Coroplast surface. Does anyone have experience with this combination, or could anyone offer advice on materials or techniques I could use avoid the perceived problem? Perhaps there is some type of primer or coating I could first apply to the Coroplast to improve adhesion?
Alternately, I could build 1-ft contours using 2mm Art Board. This would be a cellulose-based board. I anticipate adhesion of drywall compound would be less of a problem, but I am worried about the Art Board soaking up the moisture from the drywall compound and swelling up or delaminating or otherwise being ruined.
I don’t have experience with that particular foam. However, I do use the standard pink/blue extruded insulation foam that is commonly found on many layouts.
I swear by Sculptamold. Buy it in a big bag and it’s reasonably priced and even a little goes a long way. It mixes and works easily. It sticks well to the foam I use. It can be reworked or added to by moistening it, cuts fairly well with a serrated knife, and can reproduce detail fine enough to do what you want. When dry, it’s lighter than plaster, drywall compound, etc. It should travel well, although I have no experience with it like that, because of the fibers in it.
It would be decidedly superior to drywall compound.
You could use plaster cloth over the contoured surface to smooth out the steps. I use that over pink foam to get a better contour and cover gaps. My surface preference is Gypsolite, another plaster materiral, but with a gritty texture. It’s fine for my layout, but it may be too brittle for something that has to be transported.
Have you tried a craft store or art supply place to look at different types of posterboard and heavy paper stock? Any form of plastic is going to be overkill for your project, and you will spend more than for the same amount of foamboard or paper.
If you are building up a lot of layers, consider hollowing out the middle, or only doing a “full” layer every 5 or 6 levels. You’ll save on materials, and also greatly reduce the weight. That will be important if this is a large model that needs to be transported.
You never really said what you’re doing with this project, whether it’s for a model railroad or something else, but my gut reaction is that building up any kind of landscape in 4mm layers requires far more time and expense than the final product will be worth.
Why not do this in a more traditional model railroading manner? Stack up 1" or 2" thick pieces of insulating foam (such as you buy at home improvement centers) wedding cake fashion in the rough shapes of your contours. Then, use a Shurform rasp to carve the contours down to where you need them. Cover with a thin layer of Sculptamold, paint, and apply scenery materials.
If you need to be very picky about the contours, use a laser chalk line to ensure that you get the elevations exact. If you over carve, you can always backfill with Sculptamold. This method will yield a landscape that is both lighter and more durable than what you’re attempting.
Like I said, I’m not sure what the purpose of your project is, but I think you’ll have better results if you rethink your method. If you must do it your way, you should investigate a product called Gatorfoam, which is a professional modeling substance made of polystyrene and an engineered wood veneer. It’s not cheap, but it’s completely waterproof and easy to work with. You can probably find it at craft or art supply stores, and some bigger hobby shops (or on-line). The sheets are about 4.5mm thick, so that should be about what you’re looking for.
havint yet figured out these forums yet… but all i know to do rite now is just type it in by pressin reply to one of yalls commints but i was reading today that it would be better to do easements i think thats what they are called. If i got it rite then thats were you start with a large radii and thenn in the middle you have small radii then back at the end you have big radii again. I have to ask why is this better? and does anybody have any hints on how to make my track slanted on the curves? Any help would be appreciated so thanks.
Hi and thanks for your reply. I’m actually building a physical model of a proposed gold course reconstruction project. Several holes are being reconstructed, with new large landscape ponds incorporated into them. I want to accurately show the golfers how the new holes will play, using a physical model (A 2D contour map doesn’t really work for the untrained eye).
I really like your laser chalkline idea…I hadn’t thought of that. I’ve used the 1/2" and 2" styrofoam techniques in the past (for fun), but really but I really want hyper-accuracy here, to be true to the proposed grades.
I’ll also look into the Gatorfoam.
Great ideas…exactly the type of advice I was hoping to get.
Hi and thanks for your good thoughts. I have priced out 2mm art board. Based on a price per square foot per vertical foot, it’s just about the same as the 4mm Coroplast…I might still go that route, but I was concerned about what the moisture in sculptamold would do to the (cellulose based) art board. Also, it’s going to be heavier than the plastic.
I really like your idea about not wasting weight and expensive structural material on internal structure. I’m definitely going to use that advice.
OK, good advice. I’ve worked with Sculptamold for dioramas before, but I’ve never used drywall compound for anything other than drywall. I’ll take your advice and avoid the drywall compound for this application.
My son’s college design team had a similar need for fine contours to be built up. They uses 1/4" fanfold blue insulation, laminated them and then sanded the contours to achieve a very smooth 3 dimensionally curved surface (it was an airplane wing and body).
The problem with a lot of the foam boards is that they have foam sandwiched between two covering sheets and the covering sheets will give you problems. Using straight foam eliminates the difference in material at the boundry between contours.
The forums are organized around topics, which helps all of us figure out which things interest us and where we might best provide assistance and get answers. This particular topic is about making accurate terrain. To start a new topic like yours, you’d be better off clicking the “Write a New Post” link at the top of the page. That will allow you to enter the title of the whole thread, and will let others find it more easily. Give the thread a meaningful title, like “Easements and Superelevation” and a much better discussion will ensue.
Dehusman is right, in that traditional foam core has what is essentially a paper covering. It’s okay to paint on with thin paint (I’ve used it with watercolors), but I wouldn’t recommend it under something like Sculptamold, which will be wet for several hours (days even, if you use thick layers).
We’re only talking about a thin layer – say a quarter to half an inch, maybe less, of Sculptamold. Your basic scenery structure needs to be made out of foam or something similarly light and sturdy. Hollow might be even better.
You can also purchase commercial foam boards by Woodland Scenics (just about any hobby shop should have them) in thicknesses from 1/4" up to 4". While these don’t carve quite as cleanly as extruded foam, they have much smaller beads than ordinary foam, and shape much more readily, especially if you use a hot knife.
Again, though, to go back to the basic concept – what your building is for illustration only… what we call in the theater, concept and flow. You’re trying to show people how it would or could work, not provide an actual scale from which measurements should be taken. In my experience, the model says, “Here’s something to help you visualize what we’re talking about” and the 2D drawings are the official, scale plans from which the contractor or surveyor makes his actual measurements. The model has to be close, but not dead on.