Foam Mountains

To those of you that used foam to build hills and mountains, I’m a little confused as to exactly how you do it. Do you use the foam as only the base (just an understructure) and then cover it with hydocal or some other technique? Or do you carve the mountain out of the foam, then cover it with some type ground cover… i.e. grass, bushes, trees etc? Or do you do both? If you have time could you lay out the steps you use to build a small mountain?
Jarrell

Look at these links I found on the net. There is some info. But remember, this is only one of the methods.

http://www.heinepedersen.com/hyllebane/landskap01.htm
http://www.heinepedersen.com/hyllebane/landskap02.htm
http://www.heinepedersen.com/hyllebane/landskap03.htm

For my own layout I’m planning to use foam as the base, but cover it with some sort of plaster to get a better look. But I’m not there yet so I can’t give you any advice what’s best.

I layerd the foam (1" thickness as I got it free from a siding job leftovers)

I made the rough shape by layering in the contours

I did a little carving, but not too much, just to get the shape better

Layered with plastercloth (I tried paper mache first and did not like the result)

Applied rock castings

Completed the look with a layer of gypsolite plaster to get final look.

I tried going with a carved look directly in the foam, but did not like the result for the huge investment in time and effort. The plaster covering makes it much faster to get the contours and shapes and rock molds look great IMO

You can see a sequence of what I did on my picture trail site (See link in signature)

We used the large foam pieces out of computer boxes, glued together with caulking, then draped with an old Army blanket. Watery 20-minute casting plaster was then poured over the blanket and spread with a paint brush as necessary until we got it thick enough.

All of the mountains on our 20x40 foot HO scale layout are built this way.

You can see the results at http://members.cox.net/cacole2

Jarrell,

For my mountains I used 1" extruded foam insulation. Build up the mountains layer by layer, gluing them together with “No More Nails” (a similar product to Liquid Nails for Projects). Then I shaped the mountains with a Surform cutter and a thin bladed utility knife. When I had the mountains in the shapes I wanted I trowelled a thin coat of drywall compound over the works. After it dried I lightly sanded it and added another coat. Another light sanding and a final coat where I tried to leave some realistic striations in the cliff faces. The plaster was necessary to give a base for the Liquid Pigment Earth Undercoat. In places where I wanted a smooth link between the mountains and the “ground” level, I used liquid foam. I dries in about 24 hours and can be carved and plastered the same as the rigid extruded foam (it stinks a bit so I recommend good ventilation for that part).

Trevor [:)]

There’s no one way. You have your choice of any number of methods. In addition to those already presented, I have slightly different twist.

  1. I layered 3/4"foam (because that’s what I could get).
  2. Shaped with a combination of utility knife and surform tool.
  3. Sanded with different grit sandpaper to knock down the rough spots from shaping and surforming, and to add subtle elevation change/ditches, etc.
  4. Used lightweight spackle compound to fill voids or hide seams where necessary only.
  5. Painted with a latex paint, earth color.
  6. Applied ground foam.

Regards

Ed

Thank you for the links, it’s good to see how someone brings this together. It gives me more of an idea of that method.
Jarrell

Simon, I like what you’ve done. Could you tell me a little more about the trees… the near ones and the ones further back on the hill. And isn’t it amazing how the river came to life!
Jarrell

The foreground trees are Scenic Express Super trees. This is a great product and the trees you see were my first attempt. I just followed the scenic express instructions for making them. Smaller ones were used at the front of the forest on the hill, with a few Woodland Scenic fir trees mixed in. The trees further back are just small balls of the Woodland scenic fiber soaked in dilute white glue and then shaken up in bags of differnt colored ground foam. Interspersed with these are some dead plant armatures from the garden to look like dead trees. I am not completely happy with the results of these rear trees as some of the colors are not great (I have since read Joe Furgate’s thread on realistic scenery), so I plan to tone them down with some better colored ground foam.

Well, they look great to me Simon… but I’ll go read Joe’s tutorial also. I hope mine, when I get to that point, come out looking half as good.
Jarrell

Jarrell, Ed and Simon did largely what I did. I was pleasantly surprised, and very pleased with my results.

You’ll eat up a lot of valuable foam if you layer full layers; all you need is a ‘front’ to the mountain sides, so you can layer in a sort of pyramid-like shape, in profile, to your successive layers. As you woult think, the bottom two layers might be 7 or 8" wide, and the next two or three could be only 5, with the face recessed to give the effect of a slope, but the hidden edges (inside the mountain) might be flush, or nearly so. And so on.

In my case, I made the top layer removable, so that I could gain access to correct problems if I needed to. (My tunnels and a helix all run through that one mountain, so access was paramount).

Edit: P.S.- take extra care when weighting any layers on your mountain, or the next one(s) will not sit right. This is where you get creative, because even if you do it all right, you’ll still have some unevenness due to manufacturing of the foam board. Oh, well, it never goes THAT easy.

Later, I added plaster cloth and Hyrdocal to places where I needed to anchor rock castings or to make a transition, or to hide a seam. Generally, though, ye olde wire brush did a quick, if messy, job of any slope shaping. It leaves a rough look, which you can shave or sand if you like, but I left it rough and slopped the tan latex over that. When sprinkled with various types and colours of ground foam, it looked great!

This is a really good point. Many of the free offcuts of foam I had were not big enough to make a full layer, so I used expanded white bead foam from packging to fill in the interior of the hill. It is quite clear on some of the first photos on the picturetrail site.

My last layout was a freelanced WV coal line, so I needed a lot of mountains. I made all of mine with stacked pink foam carved into shape, and covered with a basic layer of latex paint and ground foam. I used plaster rock molds for any outcroppings then, but would probably just carve pieces of foam today.

I’ve never bothered with adding a layer of plaster on top of foam. Why would anyone want to spend the money to add plaster, when the ground layer is already there, and staring at them? Moreover, why would you want to add a thin, brittle, and extremely breakable layer of plaster over a nice, resilient layer of foam? If some dope whacks into foam with his elbow, you’ll just end up with a new dip in a field. If the dope whacks plaster, you’ve got a nice white hole in your scenery that you’ve got to spend hours fixing.

“…In my case, I made the top layer removable, so that I could gain access to correct problems if I needed to. (My tunnels and a helix all run through that one mountain, so access was paramount)…”

Yes, this is just one of the parts I’ve got to figure out. If I do put a ‘mountain’ where I’m thinking of, the track HAS to run under it. All well and good, it’ll look better I think. But I’ve got to have access fr

…“so I used expanded white bead foam from packging to fill in the interior of the hill…”

I guess it really doesn’t matter then what you use under there, as long as it’s lightweight, cause it’s hidden anyway.
Thanks,
Jarrell

Ray, what did you use to hide the seams between the layers of foam, just the paint and ground cover?
Jarrell

Does anyone work on hills or mountains in a separate area, things such as carving, painting and groundcover and then move them onto the layout? I’ll have an area or two that is going to be difficult, but not impossible to reach comfortably. I know I can extend my ‘reach’ by getting up a little higher but it would be nice to sit and work on these things.
Jarrell

Yep. Well, I did fill a few nasty areas with Great Stuff (foam in a can), but it’s a PITA to carve and sand. And since I was modelling WV, most of the seams were hidden by trees (I used dyed toothpicks with little - thumb-sized - chunks of WS clump foliage for mountainsides. I feel it looks a LOT better than polly fiber puffballs).

And as for getting to the tracks that went through mountains, I just made the entire tops of the mountains removeable. I hid the joints with trees, and no one was any wiser. Foam’s great for that sort of thing.

…“hidden by trees (I used dyed toothpicks with little - thumb-sized - chunks of WS clump foliage for mountainsides…”
I’ll have to remember this!
Thanks Ray.
Jarrell

Jarrell,
If you are still planning on logging or coal branch, the yard/ switching area for the industry will be over one of the end dogbones. When building this raised mountain area you should consider placing a raised section of plywood to use as a base/ subroadbed for the industrial sidings and any building foundation. After the ply is installed on support risers, the foam can be cut to build up the slopes of the hill to the decked area and the continue placing foam contours on the deck to complete the mountain. The risers can be dual purpose. Pine blocks cut over the tracks can be backers to glue the portals to. This decked area shouldn’t be too large as you need to have reach from the side access for the covered track.
Bob K.