Great Stuff Mountain?

Built my mountain with tunnels through it out of sheet styrofoam (dow insulation board) first, then went crazy with the canned foam on the outside, to get rid of the boxiness and straight lines of the sheet foam.  The spray foam is pretty unpredictable in terms of how much it expands and where it expands to, so I found it helpful to have the tunnel and general outline of the mountain blocked out first.

 

After shaping the dried spray foam, covered the whole thing with plaster cloth and sculptamold, then painted with browns and greens as a base for further landscaping.  Since mine is a tinplate layout, I'm happy with the paint and a few trees, I haven't taken the landscaping very much further (yet?).

 

In retrospect I'd say the mountain still looks a little blocky, could have used a little more spray. 

Thanks! When you can shoot us a photo or two.

Okay, but this is a little embarassing.  There is some incredible talent in scenery making on this forum, and this looks just goofy by comparison.  My "excuse" is that it's a tinplate toy layout, but I also recognize that there is a much higher level of talent and effort in much of what I have seen on this forum.   

 

That said, 

To make the open inside of the mountain for the tunnels, I glued up 1-1/2" thick sheet Dow insulation board to make a "box" with sides and a top.  Then, outside of that box, I made more mountain by stacking up progressively smaller pieces opf sheet foam, flat, like a wedding cake.  Then, a lot of great-stuff spray foam was sprayed on.  When that hardened, it was shaped, and more added as needed.  The rock faces were added, and blended in with sculptamold.  When the overall shape was okay, it was covered with plaster cloth and painted with brown and green flat latex paint.

 

In retrospect, it is still too boxy.  It's definitely a form-follows-function mountain:  it was made to house the tunnels, and to have some flat surfaces on top for the Algonquin encampment and the beacon.

 

 

I see I need some black paint on the wall inside the left tunnel! Maybe if I get inspired someday I'll add more ground cover.

There is a walkway about 2' wide between the right edge of the tunnel and the wall, when you walk back there you have access to the whole open inside of the mountain.

 

Here is a smaller hill, made entirely of great stuff.  It was started on a piece of 4 mil poly sheeting off the layout. The spray foam doesn't stick to the sheeting, so after it hardened I lifted it off, started shaping, placed it on the layout, added more foam and sculptamold, etc.

 

 

Basically, where I stopped is where the real talent would just get started.  It serves my purpose, and never having done anything quite like this before, it was a lot of fun.

Used it for my little dinosaur park layout many years ago.

 

One mistake I made was covering the foam with plaster cloth in some places a day or two later. I should have waited longer as it continued to expand very slightly over the course of several days, cracking the plaster in some places.

 

But it's a good way to rough in landforms or fill gaps quickly.

 

Jim

 

 

Yes, it expands and hardens when exposed to air.  So you don't want to make too large a mass of it.  If what you sprayed dries on the surface, what is deeper will not get air and it will dry very slowly if at all, sometimes breaking the outer crust and spewing out a day or more later.  Fun in a wierd way, but unpredictable.  Best to spray a shallow layer at a time and let dry a day or so in between, and keep building it up that way, in "lifts".  That's why I used layers of pieces of the dow sheet foam to build up an area first, then sprayed the foam on and around that.

 

That would have been a neat effect for my dino park with its very unusual looking rocks!!!

 

Jim

Well, I look at it that it's the best I can do and I'm pleased with my results. No matter how fast I drive there's always someone ahead of me. So I think your Great Stuff mountain looks great! No excuses needed.

Stu

 

 

Thank you sir.

 

How can you shape it...carve or hot wire?

Hojack, I like it!  The bright color and clean look with not too many trees looks terrific with the tin plate.  If I ever do a tin plate layout, I'll have this look in mind.

Stu, I'm a (retired) building contractor so I have an arsenal of tools that I reach for that might not be what someone else might choose for the same job.   Where I wanted to make smooth inclines for my track on 2" dow styrofoam, I glued up the foam sheets and then used a Bosch 4" electric planer with a long base to make the smooth inclines without ripples.

 

For shaping the great stuff and sheet foam mountains, I used a wild looking grinder wheel in my 4" angle grinder:

 

http://www.woodcraft.com/produ...und-coarse-blue.aspx

 

It has extremely coarse carbide teeth which do not clog.  You can do a lot of damage fast, the wheel floats through the foam with no resistance.  Because of the cupped, convex shape of the wheel, you can really do a great job shaping.  You have to be careful: it's a serious cutting machine.

 

Needless to say, both these tools make an unholy mess of magnificent proportions in a short time.  I just went at it, made sure I was done, and then cleaned up once with shop vac.   My layout is in an old barn, not in the living room, so I could get away with it.  Do they make 4" angle grinders with a vaccuum pick-up?  If so, you could contain it a little better as you go.

 

Jeff, thank you for your kind comments.  When I started this I had no idea what I was doing.  So I just did what made me happy and am having a great time.  I really enjoy the forums here on OGR, great way to share and get help & ideas with a great bunch of people.

The "canned foam" and I have a miserable relationship.  I get it everywhere and it sticks!  When my kids were teens, I had a glob of the stuff that looked remarkedly like a brain.  We had some good laughs over that one.

hojack, I think they look great.  They remind me of the foam tunnels that, who was it -  Like-Like and others used to market.

MSDS Great Stuff.  Material Safety Data Sheet Dow Chemical.

John, I agree, it is truly diabolical stuff.  Be sure the nozzle is screwed on the top of the can completely.  If it leaks there, it will get on your hand, and it is indeed the stickiest stuff in the known universe.  If you don't know it's on your hand, it then gets in your pocket, in your hair or beard, and it's really downhill from there.  Do not under any circumstances touch the foam until it is rock hard.  The only way I know to get this off my hands is to wait until it is hard and then grind it off with a pumice stone.

 

It is polyurethane foam, not polystyrene (styrofoam), so I do not know whether hot wires work with it.  I'm not a fan of hot wires, I can't stand the vile fumes.  Wear a dust mask if you use a grinder to shape it.

 

But it's a lot of fun for forming mountains and other terrain.  As somebody said, "You ain't havin' any fun if you ain't gettin' any on ya!"