[niceguy]

Anyone ever tried working with expanding foam, then shaping it once it cures ?

It seems like such a messy way to do things, but it does give you the freedom of shaping anything and anyway you like.

Just curious if any of you have tired it and your experience.

 

[Lorne]

I've used it at work but never for a layout. I can see it being more of a hassle than help. When it's wet it sticks to absolutely EVERYTHING and hard to cleanup.

One idea I read about in a train magazine showed this guy using that blue styrofoam insolation (2 inch stuff). Cut it to rough sizes and variouis, then placed them on edge to create a rocky type mountain. It'll be alot easier to cut then expanding foam and easier to clean up.

 

[niceguy]

I am worried about the clean up too! I remember spraying it once to seal a door and the stuff was just stuck everywhere. I thought maybe if it cured it would be a smart way to do things....

i may look into this blue foam you're talking about.

 

[ptg4n6]

Try the blue extruded foam.
It can be purchased at most home improvement centers and comes in 1" and 2" thick.
I have just completed my first layout and the foam was easy to shape and not terrible to deal with regarding clean-up. A small shop vac works very well if you have one.
NOTE: Make sure that when you secure it to your benchwork, or when stacking pieces for sculpting...use a FOAM COMPATIBLE adhiesive. If you don't, the adhiesive will distort the foam significantly.
I hope this helps...

 

[alfalfa]

I made my first mountain with GREAT STUFF. That is what you are talking about. I liked the finished project but in the future I will go with 1" - 2" thick foam insulation sold in sheets like the above advice.

 

[ntrainlover]

Your best bet is sheet foam.

 

[sptrains.com]

I still like the whole woodland scenics system as far as easiest to use, and least mess. One note about expanding foam, make sure the room is well ventilated, and no open flames, under the right conditions that stuff can form cyanide.

 

[ntrainlover]

What I use is That 1 inch foam board, I shape it, then I glue it. After a while I cover it with plaster cloth to stregthen It. A little while later I com back and fix it with sculptamold. Then the woodland senics stuff goes on. This is how it looks.

 

[sptrains.com]

Cool, it could be the picture but it looks like your curve has a nasty kink in it.

 

[ntrainlover]

no, there is a little tiny piece of straight in it.

 

[T-Man]

Liquid Nails

[ NOTE: Make sure that when you secure it to your benchwork, or when stacking pieces for sculpting...use a FOAM COMPATIBLE adhesive. If you don't, the adhesive will distort the foam significantly.

I heard through a crafting source, that you can use Liquid Nails. It's a tube you can use with a chalking gun and easy to apply.
Model airplane glue is definitely OUT, unless you need to make a crater.
Don't say I didn't warn you.

 

[sptrains.com]

I think liquid nails would be way way overkill. Elmer's does the job fine. You really don't need a whole lot of glue, since 99% of the forces will be compression. And Elmer's will hold well under any of the shear forces you'd expect with a layout. I did all foam and it's constantly being played with at the store and by my 3 year old when he visits. No problems at all.

Josh

 

[Lownen]

I think liquid nails would be way way overkill. Elmer's does the job fine. You really don't need a whole lot of glue, since 99% of the forces will be compression. And Elmer's will hold well under any of the shear forces you'd expect with a layout. I did all foam and it's constantly being played with at the store and by my 3 year old when he visits. No problems at all.

Josh

If you mix Elmers or other white glue with water 50/50 or there abouts (64/36 should be fine) you can apply it with a brush and get a nice even coat on one surface to bind the next layer too.

 

[Don Chovanec]

Another negative on the expanding foam, it has a pretty powerfull push and could just rip apart your frame if it got into a crack. I saw something that I am going to try. I is a light green foam block about 4 inches square and 12 inches long. It is used for flower arranging decorating and is a fine grain. It does absorb water but I dont think it swells so I am not sure what will happen I may have to wrap it in plastic wrap but hey ya gotta try. Anyone tryed this. Also at this store Michaels they had an electric slicer for styrofoam that looks like a cooping saw. for 7.99 I am going to find out what the heck that does. I have used the foam sheets mentioned and some wire frame papermeigh ah I can't spell it. Paper sheets soaked in plaster and had some interesting results. I am always looking at how can I use common things that are also cheap. The cheaper the more I can use. I have used that Sculptmold and it was great but costly to do a whole lot. Of course I am trying to think downsized but I have such a grander view looking up!

 

[Don Chovanec]

Wow I cannot type fast enough or maybe I talk too much . . . Yeah that must be it. The thead is change by the time I post to a new venue!!!

 

[stationmaster]

If you mix Elmers or other white glue with water 50/50 or there abouts (64/36 should be fine) you can apply it with a brush and get a nice even coat on one surface to bind the next layer too.

Exactly what I normally use. Another good product is the craft "Spray Tack", a 3M product I believe. It is a tacky spray glue meant for foam projects. Bad part is it is like a contact cement. You'd better be right the first time. Ain't no "do overs".

 

[JPIII]

I use a lot of expanding foam......it's the cat's ***, IMO.
Clean up is easy with lacquer thinner......even the applicator nozzle (tho Not on your foam) but have some paper towels standing by for wipes of spillage. I coat the stuff with light weight spackling compound (suitably thinned for workability). The LWSP is not very stout but it sands & shapes easily (but you don't want the dust in your nose).

The best EF is the windows/doors stuff. *Mostly* it sets up at around 3X the applied size and free of voids.

Wanna build a mountain? Lay down a blob of EF. Let it set for a couple hours, lay down another blob....keep going till you reach the ceiling, let the whole works set up for 24 hrs. cut to shape with a roughly sharpened knife (bench grinder/decent file is gud). The EX IS compatible with blue, pink, & white foam and WON'T push your layout apart. Save your EF drop from cutting.
Great for undulations in flat surfaces....just glue it down & carve.

5-7 bucks a can at about any hardware store.

 

[tjcruiser]

Our member Swiggy has had great success using expanding foam to construct his southwest themed layout. Here's just one of his many threads ...

http://www.modeltrainforum.com/showthread.php?t=9347

TJ

 

[Carl]

Expanding foam was tried by a local club - NASA N Scalers. They shoot the stuff out of a can and before they could get to it to shape, it hardened. Made a really mess.

Liquid Nails and caulk works great for securing foam.....as noted above, please make sure you use water-based Liquid Nails or caulk. Petroleum based products will dissolve foam.

 

[JPIII]

I got a care package of tunnel portals today and have a design error to fix.
I'm waiting for the EF to cure as we speak......BTW, there are no brain surgeons in my family.. Tomorrow I'll carve to fit. I've suffered no degredation of the blue foam/EF interface. I got the EF tip from a fella named Doug in Grants pass, OR. He's one sharp fella. .......