Instead of hi-jacking the other posts on foam... (seems to be a hot topic this week!)
Now that I have track grading worked out I am ready to set my risers. For those not following along I am working on my phase 1 which is an 8x6 loop area. I envision this to be a mountain valley with terrain rising up on the two sides against the wall with a drop-off into a gorge at the corner where they meet. In order to get enough depth for the rolling terrain and gorge I am thinking of setting the risers for my base track level at 4". Then lay in foam sections at appropriate heights and shape it. I never worked with foam before, so there are new tricks to be learned.
I don't see any problems getting the foam shaped the way I want. I have an assortment of knives and the wood shavers mentioned in the other post. And playing around with it a bit the foam seems a lot easier to work than sheet metal and bondo (that's another hobby!) But with all the different sections I will end up with a lot of seams, no doubt will have some unintentional gouges, and will need to join it in with my ply sub-roadbed.
I assume that I will need to glue all of this together before the final finishing. Would foam-compatible caulk work best for all of these type of joints and seams?
And I will need to finish detail the seams- plaster or Sculptamold? I never used Sculptamold before so not sure how easily it works or how hard it sets up. I understand hydrocal is the "standard" for model RR hard terrain, but how much different is this than the Dap plaster of paris that is readily available? They both should have a gypsum base. I used locally available plaster of paris last time for all the terrain and it worked fine, but that was 25 years ago and maybe product formulas have changed?
This time I am modeling eastern terrain instead of western, so will end up getting a lot more involved with grasses, trees and other ground cover. But I will still have some rock faces and will try creating these with the foam. If I am not satisfied then will go back to the plaster methods that I know work well. Any issues with applying plaster using forms directly to foam?
Huntington Junction - Freelance based on the B&O and C&O in coal country before the merger... doing it my way. Now working on phase 3. - Walt
For photos and more: http://www.wkhobbies.com/model-railroad/
Several months back I had exactly the same question. I got many helpful answers, but in the end it was experimentation, experimentation, experimentation.
http://cs.trains.com/mrr/f/11/t/209831.aspx
I have figured out what is wrong with my brain! On the left side nothing works right, and on the right side there is nothing left!
Connecticut Valley Railroad A Branch of the New York, New Haven, and Hartford
"If you think you can do a thing or think you can't do a thing, you're right." -- Henry Ford
HObbyguyIn order to get enough depth for the rolling terrain and gorge I am thinking of setting the risers for my base track level at 4". Then lay in foam sections at appropriate heights and shape it. I never worked with foam before, so there are new tricks to be learned. I don't see any problems getting the foam shaped the way I want. I have an assortment of knives and the wood shavers mentioned in the other post. And playing around with it a bit the foam seems a lot easier to work than sheet metal and bondo (that's another hobby!) But with all the different sections I will end up with a lot of seams, no doubt will have some unintentional gouges, and will need to join it in with my ply sub-roadbed. I assume that I will need to glue all of this together before the final finishing. Would foam-compatible caulk work best for all of these type of joints and seams?
i've glue foam using yellow wood glue spread thin with an old credit card. I'm hand-laying track on strips of homasote glued to 1" foam glued to 1/4" luan on l-girder.
i also wonder how well a hot air gun could be controlled to shape foam. a piece of cardboard could be used to block hot air to help control what sections of foam get shrunk, perhaps a piece of cardboard with a hole in it (an old photographic technique). I also wonder if it can be used to smooth and texture the surface shaped roughly with knives.
12 gauge copper wire can also be bent and used with a soldering gun for shaping. It's not a precise as a thin piece of wire, just holding it near foam would probably cause shrinkage.
mixing waste foam with wood glue could also be used to fill gaps/gauges. I wonder if plaster would eventually crack if it spans a seam.
greg - Philadelphia & Reading / Reading
I got my foam shaped the way I wanted stuck together with latex caulk. Used Sculptamold to fill in between pieces and in any dings that needed it. Has lasted a number of years and has not cracked or seperated. I'd be afraid that hydrocal/plaster might crack.
Good luck,
Richard
stebbycentralin the end it was experimentation, experimentation, experimentation.
Good point, and not sure why I didn't think of it before reading your response, but I still have my small 46" square test board that I used to experiment with laying down roadbed and track with caulk, and then different ballasts, and then a turnout with a tortoise. I might as well go the next step and build up some terrain on it using foam and various plasters. I'll order some hydrocal and sculptamold, and try some of the locally available plasters and see how it all works on the test board. Its turning into a "mini layout" of sorts.
I've done searches that have answered a lot of my questions and the links provided here were good ones. But I guess there's nothing like direct experience.
I use Great Stuff spray foam to fill in cracks and gaps (and even to glue two sheets of foam together, use bamboo skewers to hold things in place). You have to wait 24 hours before trimming or shaping (or it will shrink). Wear gloves.
You can carves rocks right into the foam, I add "paint texture" to the paint when I paint the rocks.
Jay
C-415 Build: https://imageshack.com/a/tShC/1
Other builds: https://imageshack.com/my/albums
I already glued together some foam scraps on my test board using both white glue and caulk. I am going out of town on business the next few days and it should be dry by the time I get back. I'll start carving and plastering to get a feel for the various materials then.
I was just looking at the Scenic Express Super Trees last night. I think trees are still a good bit down the road for me but I will need a lot of them and the pictures sure look good. Do you have any photos of the ones that you made?
I just laid some pink extruded foam for my sub road bed and I used red devil premixed vinyl spackel. $6 for small tub (little less than a pint). It dries hard and I smoothed it with a foam sanding block and then I tried a random orbit sander on low speed with a 220 grit pad and it worked great! Again this was for small 3/8" gapsb its thick enough I suppose you could fill in larger gaps with it.
I'm a big fan of Sculptmold. You may have to roughen the surface some or stick some bamboo skewers to get it to bind well to the foam.
If you have a flush joint to conceal between two pieces of foam or foam and wood, I had good luck taking 0.010" styrene sheet, cutting as needed (I made a street with mine), and gluing it on one side, leaving the side hanging over the other sheet unglued. This really hides things.
This is not the best shot, but all the town area past the back track is on a sheet of foam that lifts out. As you can see, there's no obvious joint between it and the track. The edge of the styrene sheet rests on the wood subroadbed, then I just painted/scenicked over it.
Mike Lehman
Urbana, IL
For gluing smaller pieces of styrofoam I use a low-temp hot glue gun.
Just a quick update. I ordered 20 lbs of Hydrocal and a bag of Sculptamold from e-bay and built a little rock formation on my test board using two sheets of foam carved to shape, a plaster cut rock face toward the bottom, and used some Sculptamold to blend. More or less a test of various methods just to see what happens.
Gluing the foam together seems to work fine with either white glue or the Alex Plus caulk that I am using for roadbed and track. So sort of settled on the caulk as a standard.
The plaster works just like I remember so making the cut rock face was easy. Sculptamold is wierd stuff and this was my first experience with it. Seems most useful for filling/blending and adding texture. And I was not too sure what to expect from the foam. I carved and distressed it a bunch of different ways, again just to see what happens. And I put a ton of paint washes on the finished structure just to see what I liked- got a bunch of potential colors from the local Hobby Lobby.
Things I learned- Everything seems to stick to everything, so no problems there. Don't get the housepaint used to seal the foam on the plaster or Sculptamold or they won't "take" the acrylic wash. And too many wash colors are not a good thing. But for an experiment, the end result is actually presentable. So now I am confident, and attacking the foam on the layout and getting the basic landscape shaped. And I already started another test rock structure using my "learnings". Should keep me busy for a few weeks.
A lot of good suggestions made here, got me kick-started which was exactly what I needed!
I have always used plaster of paris, and joint compound with great success. I have never had an issue with blending it into rockface molds and using it on foam. I make my own plaster cloth by using used fabric softener sheets dipped in plaster of paris mixture.
Sorry for the late arrival.
I love hydrocal.for several reasons. My layout is a 10' x 16' and I also wanted a deep gorge. The picture of the gorge was built with cross strips of cardboard taken from a regular cardboard box, covered with newspaper which allows me to form any way ( Straight deep sides) . I then cover with small pieces of paper towel soaked in HYDROCAL. Hydrocal cures to 5000psi strength so once it cures you can remove the entire underbase if you wish. If you are going to build a tunnel it is even better. Shape newspaper over the track, Put on Hydrocal and remove newspaper. Leave an open grid on your train table so you can always get to a derailed train or maintenence.
You can put house paint in the hydocal so it will give you a base color with color all the way through.
Use the plaster of paris to fill in line between the strips.
One disadvantage or advantage which ever way you want to look at it is that hydrocal sets very fast. Mix in small batches. Use a tablespoon of vinegar in the mix as a retarder.
Harold
hwolfI love hydrocal.for several reasons
Yup, plaster cloth over cardboard strips and newspaper was the way I did it years back, so well in my comfort zone. I didn't have a gorge nearly as big as yours back then, and this one will be somewhere in-between. But this time I will be modeling Appalachian landscape so it is more about forested hills with rock accents. I am finding the foam really good for hills, and its a lot easier to "plant" trees in it. But I still feel more comfortable with plaster for rock formations. Just got to get the color right (the red and yellow shades have to go- too much of a western look) and work out how to blend the two materials to my liking.
I really enjoy building wooden trestles- I think there were some still left in coal country into the middle-late 1900's. If not, who cares- its my railroad!
Going to close this one out with a picture of my test version 2. With the lessons learned from version 1, this time I actually spent some time really modeling. The photos show the kind of textures and colors I was aiming for this go-round. Pleased to find out that I really do remember how to shape and carve plaster.
Based on the testing I am going to stick with plaster for rock formations and use foam for general landscape/terrain. I think I have methods for combining them and getting everything to stick together pretty well worked out. A couple more test structures to get the cobwebs out of my fingures and I will be ready to start on the actual layout.
Still need to work out my methods for ground cover, vegetation and trees. The new-fangled foam stuff I bought to play around with isn't quite doing it for me yet.
Thanks guys for the advice and encouragement!
HG, I'll share an idea I read about years ago and will be incorporating it into my layout. I did some experimenting with it and it turned out great. Even on my first attempt.
I took a small chunk (roughly 6"x 6") of low density foam, like in furniture cushions, and started picking at it. Pinching off small peices here and there until I got the shape and size of rock I wanted. Then I took Bathroom and Kitchen calking from Dap (white latex) and smeared it all over the rock faces. Once dry, I merely painted it the colors I though might look good. Even took an old toothbrush and flicked some paint on to get that speckled look. The Dap is the trick here. This stuff is perfect for paintability, flexability, and seals seams. It's also an adhesive (to some degree). You can apply it to the edges of your foam layers to where it'll ooze out. Then it's a simple job of smearing it into the seams to fill them in.
Lorne