I want to buy several sheets of Expanded Polystyrene (R-Tech 2" x 8’ x 4’ Insulated Sheathing) as a base for our layout. Is this the right kind of foam to use? Won’t melt or cause a fire hazard?
Thanks!
It’s what I use, the main disadvantages are it is not as strong so you need to brace which you would normally do anyway. You need to cover the final surface with something like plaster cloth, some of the other foams you can cut to shape and paint. As far as fire hazard it dose melt easier but from all the research I have done I have not found any evidence of it being better or worst in the way we use it (now if you were using it to build a house, that is a different mater). It dose not give off any toxic gases when you cut it either if you stay below 450degrees, Woodland Scenics foam cutter comes in at 425degrees and that is not a coincidence. If sound is a concern you may want to put the foam on ply as straight ply or straight foam is noisier but it dose not seam to mater what thickness ply you use as long as you use 2"foam. I use the same brand only in the 2’x4’ size as I am building modular. You can use foam board for backdrops too which I was told was impossible, as an added note.
I think you really want extruded polystyrene rather than expanded. The R-Tech has a facing that might limit your creativity.You might want to do a quick search of the forums for this topic.
Karl
The facing peals right off, no problem.
I have used the ‘pink stuff’ and have been very satisfied with the results. It does shred a little when it is worked with a Sureform tool but if you have a vacuum clean-up is pretty easy. The foam cutter by Woodland Scenics works well but I am not too sure about the vapors. Whatever you do don’t buy the ‘whitestuff’ - when it is worked it goes everywhere.
As far as using foam as a base the only thing I have read is that you can’t lean on it like you can plywood and it will dent easily.
You can’t work the white stuff but you can gouge it but realy only cuts well with a hot wire though I have used a fine saw to rough cut at times.
Extruded Styrofoam. Yes it will melt. I used a halogen light for track laying and ended up with a little lake bed. Yes it will burn. If you house burns down it will cause fumes.
That set aside, in any normal conditions, it is wonderful stuff and safe. For instance, a soldering iron will melt a little hole, but will not start a fire. I use it for everything. Pics of my floor to ceiling canyon are included in my sig.
My advice, get a steak knife for the main cutting tool, and don’t expect much from a hot wire. As for mess, it is way less than plaster if you have a vac close by.
Glad you did some research like me, model railroading is getting filled with people not doing any research on a subject and just going with what others have said who go it from someone else (don’t know how many times I have heard about illegal foam in California). Love your canyons.
Just curious-- if you’re going to cover it with plaster cloth in the end, why use it at all? Why not just go with the hardshell (plaster / plaster-cloth) ?
John
John, You are right. I do not cover my foam with anything but a little ground goop for texture and then paint for color. For fine carving I don’t even use ground goop, just paint and what ever follage is called for. However, stacked foam is easier for general buildup than cloth and I think less messy. I think that is what Twhite uses to GREAT effect.
I have definitely seen some good work using both methods!
John
The reason to build up with foam is it is easier to change the shape and add to before you get to the final layer it is just like playing with blocks, it is really light weight also. I like it because when I have a tunnel I can leave access holes and have seen some people cantilever so the whole backside behind the mountains is open.
One word: Catzilla.
I use foam covered with sculptamold, because it will hold the weight when the stupid cat gets up on the layout. Hardshell cracks under the weight of the beast, requiring more extensive repairs.