Using foam to make mountains

[mikesmowers]

I am wanting to make a mountain with a tunnel or two using 1/2’’ blue foam board and need some advice. I have seen pics of other mountains here that look simply great and I would like to know how you do it. I am thinking of making a base mountain from the foam and use some rocks I have cast from WS rock molds for some of the clifs, can this be done to look real? Also how do you carve the foam into washes, gullys, and rocks, and what do you use to cover it with, some form of ground goop if I understand correctly.

What is the best to use to glue the foam board together? I know this is a lot to ask but I know it can be done to look great (Art Hill) but not sure I can do it. Please help me in any way you can, a tutorial would be nice if you have one.

I want to get some knowledge before I start so I won’t be totally in the dark, I have got 2 pieces of foam and will be working on the N scale for now but will want to make some for the HO scale when I get to that point. Thanks for the help. Mike

[davidmbedard]

http://www.youtube.com/watch?v=D1D4KBB_GC4

David B

[loathar]

I used Liquid Nails “For Foam” to glue mine together. Covered it with Sculptimold. A long blade razor knife works great for cutting it and basic shaping.

I did a couple corners like this. I used screen and card board for my big mountain.

[Kenfolk]

There will likely be lots of different ways presented here, but I used a serated long-blade knife for general cutting to shape, then used a Surform tool ( a small one with a large handle–these tools have cutting edges like graters, if you are not familiar with them) to get to the shape of the hills and valleys.

I like the Liquid Nails adhesive, but I use drywall screws to anchor the layers while the glue sets up. I’ve covered mine with acrylic house paints of appropriate colors (usually mixed from leftovers hanging around) and applied with sponges after a good solid coat of a light color to make sure the re is no foam showing through. I start light (greys and browns along the right-of-ways, tans, browns, and greens, stippled throughout the countryside. Greys again in the city. This gives me a base of color for whatever I add on top of that. It also seals the foam. Where needed, I can add drywal compound or other stuff to get a better surface. Trees just get stuck in the foam.

I’m getting ready to start the process all over again for my layout expansion; just assembled the table this afternoon.

[CNW_6000]

I use Elmer’s Glue (not diluted) between layers and use wood screws to hold the base of the mountain to the surface.

[ARTHILL]

Yes, you can surely do it.

I get my foam from construction sites, but prefer 2" if I can find it.

I glue it together with lowtemp hot melt glue ( I use WS), because it is faster, but latex caulk holds a little better ( it may may take several days to dry between layers of foam.

I glue up piles of chunks - the key, make it too big, though pieces can be glued on later easily enough. Don’t worry too much about holes, they make great caves or can be filled later. Ad castings if any when the basic shape is set. Just carve out a hole and glue the castings in. A little Drywall mud will fill the gaps.

I carve mostly with a steak knife. Key, carve too much, not too little. Don’t be careful. I use a hot wire for hoodoos and a wire brush for finishing.

Know your geology, which way the layers run if any. Sedimetary rock will have straight parralal lines. These with be horizontal unless tilted or bent by plate tectonics. Sandstone, limestone, shale etc are examples as in the Grand Canyon or the Mississippi River Valley.

Volcanic upthrusts will be vertical by shape as in the Superstitions and Devils Tower.

A wire brush will add lines at the end of the carving.

If I have carved precise detail, I paint with artist acrylics, directly on the carved foam. For places where there is some weathering and dirt, I use my version of ground goop (Premixed light weight drywall seam compound, saw dust, latex paint for color, Lysol for mold and enough water to get the consistancy right. I paint it on with an old brush.

I then recarve and repaint until I like it or get bored.

To make a tunnel, make a stack and blast the hole with the steak knife, jusat like the prototype.

Expermentation is more useful than instruction, however I will be happy to expand on what I know if asked.

There are pics in my signiture, and though they are not neatly ordered, there ar a lot of process pics of the canyon and the mountains.

[Gazoo]

I saw a picture recently that looked like (but was not) Great Stuff. You know, the light brown stuff that comes out of a pressurized can, fills gaps, expands as it dries, is sticky as all heck until dry?

Has anyone ever used this for mountains? If paint would stick to it, it might make a nice rolling hill for $3 a can and almost no effort. Lightweight, low mess (unless you cut it), other advantages?

[davidmbedard]

I saw a picture recently that looked like (but was not) Great Stuff. You know, the light brown stuff that comes out of a pressurized can, fills gaps, expands as it dries, is sticky as all heck until dry?

Has anyone ever used this for mountains? If paint would stick to it, it might make a nice rolling hill for $3 a can and almost no effort. Lightweight, low mess (unless you cut it), other advantages?

The difficulty is that you have NO control of where the stuff ends up.

David B

[Kenfolk]

I saw a picture recently that looked like (but was not) Great Stuff. You know, the light brown stuff that comes out of a pressurized can, fills gaps, expands as it dries, is sticky as all heck until dry?

Has anyone ever used this for mountains? If paint would stick to it, it might make a nice rolling hill for $3 a can and almost no effort. Lightweight, low mess (unless you cut it), other advantages?

The difficulty is that you have NO control of where the stuff ends up.

David B

Anyone tried it directed into a form?

[loathar]

I saw a picture recently that looked like (but was not) Great Stuff. You know, the light brown stuff that comes out of a pressurized can, fills gaps, expands as it dries, is sticky as all heck until dry?

Has anyone ever used this for mountains? If paint would stick to it, it might make a nice rolling hill for $3 a can and almost no effort. Lightweight, low mess (unless you cut it), other advantages?

I saw a video of a layout builder in Michigan. They use card board and screen to make the basic terrain and then use a spray on foam to cover the screen. They had an industrial pressurized spray setup though. They weren’t using cans. Basically like thick spray paint.

Kenfolk-We used a 2 part liquid foam at a company I worked at. We sprayed it into molds of various shapes to make packing corners for shipping equipment. It holds the shape of the mold well after it sets up, but it sticks to anything! We had to put those grey plastic bags into the mold and spray the foam into the bag. Otherwise the foam will just stick to the inside of the mold. That type of foam works great for grinding up and coloring to make home made ground foam.

[bogp40]

Yes, you can surely do it.

I get my foam from construction sites, but prefer 2" if I can find it.

I glue it together with lowtemp hot melt glue ( I use WS), because it is faster, but latex caulk holds a little better ( it may may take several days to dry between layers of foam.

I glue up piles of chunks - the key, make it too big, though pieces can be glued on later easily enough.

Arthill,

I used to use all the other glues and adhesives, but the hot glue is the best, especially if you want to keep on building and fitting those pieces.

My first choice for large mountain/ hill constuction is cardboard lattice or wire screening, but all the smaller areas and shapes are done w/ foam.

[mikesmowers]

I would like to thank all those that replied, lots of good advice, I did watch the videos and would like to go over them again then will start the mountain. I will be keeping you posted and asking more questions as I go. Mike