# foam buildings



## mymodeltrain (May 14, 2013)

Can buildings made of foam survive outdoor? I guess if we spray water proof solution they will be stronger but I am not sure if they can survive in the heat.


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## BigRedOne (Dec 13, 2012)

Foam seems to be a common material used for modeling buildings.

Keep in mind, a foam for insulating homes would be exposed to the high temperatures of an attic.


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## mymodeltrain (May 14, 2013)

"Keep in mind, a foam for insulating homes would be exposed to the high temperatures of an attic".

Good point, thanks.


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## JackM (Jul 29, 2008)

What happens on a windy day? Ya got buildings blowing around all over the place, like a bunch of tumbleweed?

JackM


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## Ironton (Jan 2, 2008)

Many people stake them to the ground or screw them to a heavy base. Thus the buildings are as wind resistant as any other material.

Ray Dunakin's buildings are being made of plastic sheets, they cannot be much heavier than a foam core.


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## cape cod Todd (Jan 3, 2008)

Hello
I have just started using foam for building. In my case I was considering building an arched stone bridge out of concrete. I asked on another forum and it was suggested I use foam which I did. I am very happy with the results. I used 2" foam insulation and stuck it together to make a 16" wide structure. I then used a wood burning pen to make the mortar lines and then painted it with several coats of latex and to give it a stone look. I was told that ants love to build nests in foam so I was sure to seal up every crack with caulk and paint. The top of my bridge is made from hardibacker also painted since it is not water proof but it does add weight. 
I don't know if this link will work to a photo of where the bridge will be going but here it is. http://freightsheds.largescalecentral.com/users/capecodtodd/_forumfiles/NewFoamBridge.jpg


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## mymodeltrain (May 14, 2013)

I have just started using foam for building. In my case I was considering building an arched stone bridge out of concrete. I asked on another forum and it was suggested I use foam which I did. I am very happy with the results. I used 2" foam insulation and stuck it together to make a 16" wide structure. I then used a wood burning pen to make the mortar lines and then painted it with several coats of latex and to give it a stone look. I was told that ants love to build nests in foam so I was sure to seal up every crack with caulk and paint. The top of my bridge is made from hardibacker also painted since it is not water proof but it does add weight. 
I don't know if this link will work to a photo of where the bridge will be going but here it is.



I can't imagine that the bridge is made of foam and wood. It looks really a stone bridge. Do you have a movie or photos to show to make this step by step?


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## MikeMcL (Apr 25, 2013)

I guess I will find out. I have "carved" foam insulation into tunnel portals that have been fine outside for over a year, but they only see a few hours of below freezing temperatures during only a couple nights in the winter. Recently I built this train shed. The structure is self supporting, the foam walls are just a facade, glued on to the supports.










Here is my method of "carving" the foam with a soldering iron and wire brush.


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## mymodeltrain (May 14, 2013)

I guess I will find out. I have "carved" foam insulation into tunnel portals that have been fine outside for over a year, but they only see a few hours of below freezing temperatures during only a couple nights in the winter. Recently I built this train shed. The structure is self supporting, the foam walls are just a facade, glued on to the supports.




Thank you for sharing the video. It is amazing. I am getting more interested in making structures with foam. When you glue the foam together, do you use outdoor wood glue?


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## MikeMcL (Apr 25, 2013)

mymodeltrain said:


> Thank you for sharing the video. It is amazing. I am getting more interested in making structures with foam. When you glue the foam together, do you use outdoor wood glue?


In this application, I used 100% silicone to attach the foam to coroplast (corrugated plastic) backing that I got free from a sign making friend. Then the coroplast was attached to the metal studs using liquid nails. 

You can test any glue on a scrap of foam to see if it will attach the foam, or melt it.


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## cape cod Todd (Jan 3, 2008)

MikeMcL was actually my inspiration to try working with foam. Watch his movie he has a nice process that gives you terrific results. Thanks Mike.
As for gluing I tried a scrap piece and tightbond 3 woodglue and it worked. I bet silicone would have been a better choice. Whatever you use try it on a scrap bit of foam. The last thing you want ot do is have the foam react to the glue.


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## ewarhol (Mar 3, 2014)

MikeMcL said:


> Here is my method of "carving" the foam with a soldering iron and wire brush.
> 
> http://youtu.be/RNNGJnAvH9A


Great video! Makes we want to work on a tunnel portal tonight. What else do I do during an April blizzard in Minnesota???? Apparently it's too much to ask for spring.... sigh...


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## MikeMcL (Apr 25, 2013)

Thanks, I didn't invent the method, it is from reading about other people's techniques, documenting and sharing information.


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## toddalin (Jan 4, 2008)

I alternately sift hydraulic cement/spray with water over my Styrofoam structures to make a hard waterproof shell. This was documented here on-site and in _Garden Railways_ Magazine.

To make "hollow rocks" (but could possibly do structures like adobe), I don't even use the foam anymore. I make the rock from wire mesh and cover it with masking tape. Then, from the inside, I sift/spray until the mesh is embedded. Then I turn it over, remove the tape, and sift/mist the outside until the mesh is embedded.

BTW, these are both foam. They were made by "Mountains in Minutes."

http://www.trainweb.org/girr/todds_site/jun_00/brick_building.jpg

http://www.trainweb.org/girr/todds_site/jun_00/brick_building_2.jpg


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## CliffyJ (Apr 29, 2009)

Be sure to check out Winn's ("placitassteam") build threads, his foam models are amazing. 

http://forums.mylargescale.com/14-buildings/24082-buildings-zia-columbine-rr.html
http://forums.mylargescale.com/14-buildings/18540-church-taos-pueblo.html

Here's my newbie meanderings,
http://forums.mylargescale.com/14-buildings/24771-structure-sub-wall-materials-5.html
http://forums.mylargescale.com/15-model-making/32377-hale-norcross.html

===>Cliffy


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## Jerry Barnes (Jan 2, 2008)

I think people have used Sculpey(or something like that) and stucco on them. I just used latex paint. GOt something eating on it though, real smooth depressions eaten out, so I know it's not birds.


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## MikeMcL (Apr 25, 2013)

Some excellent examples of foam buildings in those threads mentioned above!


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## Crisolite (Jan 9, 2008)

Chris Walas make his Lemurian Temple out of foam.
He describes his process on his 4Largescale site
http://4largescale.com/chris/c17.htm


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## toddalin (Jan 4, 2008)

I use Titebond III. Many adhesives will "eat" the foam, so I like to stay with water-based materials and paints (e.g., "Patio Paint" or "Apple Barrel").

Of course, if you sift coat it with hydraulic cement, you can paint it with whatever you like (e.g., rattle cans that would attack the foam).


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## Sjoc78 (Jan 25, 2014)

Seems like a decent exterior grade paint should hold up for a while and help protect the underlying foam from UV. As long as its securely fastened down and painted on all surfaces that should see weather or sunlight it would be OK.


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