# Modeling in Foamboard



## Mike Flea (Apr 8, 2014)

Well, this isn't my first rodeo, I've used blueboard in the past for mountains and scenery on an HO layout my wife and I worked on, in my mother-in-laws basement. However, this is the first time I'm using foamboard outside in the elements. I decided on 2" Pinkboard for forming and shaping the mountain on my elevated layout out in the veggie garden. It's a simple, lazy dogbone oval, ("L" shaped), with a 4' diameter circle in each of the ends of the dogbone, laid out on top of 1" marine plywood, supported by cinder blocks( 20' on the house side), and bolted to the fence,(40' through the garden).
I attached the first layer(base) of the mountain using bolts, fender washers, and wingnuts, to the plywood. 2nd and all additional layers are glued together with Locktite PL 300 Foamboard construction adhesive. After creating the first mountain, I started the second, which would include a mine. The first mountain build was started around the end of May this year, and was completed a week later. I purchased a "Hot Wire" foam cutter to do the detail cuts, ( I had remembered the mess the wife and I had using a hacksaw blade and wire brush to form the mountains on the previous layout). Since then, I haven't put anything else on the first mountain because I wanted to paint both mountains at the same time.
So here it is, the end of June, the last 30 days have been mostly in the 80's and 90's, and we've had some heavy rainstorms along the way. Because I work 10 hr days, I've only been working on the railroad on the weekends. I bolted the base foams down yesterday for the mine section and tunnel. I also noticed yesterday that the top and other exposed horizontal pieces of the first mountain have a green powdery dust on them. If I wipe my hand across it, it does come off. I'm assuming it is the decomposition of the exposed foamboard, so that will have to be washed off before I paint or try to adhere anything to it. 
I had thought about using a "Foam Coat" to cover it prior to painting, but I read somewhere that just using an exterior latex paint is ok to do. I also don't want to add too much weight to the elevated layout, or lose my details that I carved into the foam. I also read that a lot of these foamcoats are nothing more than a thicker gesso, and at twice or three times the cost, I'll just use the gesso.
I'd like to hear from others that have used closed cell foamboard on an outdoor layout.


----------



## CliffyJ (Apr 29, 2009)

Mike, thanks for starting this build thread! Please post some photos as you progress, I'll be following with interest.

Have you seen Winn's threads? They might be helpful for your purposes. But someone needs to help me with the links...

===>Cliffy


----------



## Homo Habilis (Jul 29, 2011)

CliffyJ:

Is this the thread of which you speak? -  Buildings on the Zia and Columbine RR


----------



## Mike Flea (Apr 8, 2014)

Wow, that's impressive. I like the idea of using stucco, I think it would fill the gaps between layers.


----------



## Mike Flea (Apr 8, 2014)

Here's some shots of the layout and the mountains. In the last photo, you can see the green dust. The hole in the side of the tunnel is for derailment rescues, it will get a door for access, and the siding off the 4' diameter track is part of the mine. Along the fence, between the two mountains, is going to be a carved foam panel to simulate another mountain. It's a work-in-progress, doesn't look like much now, and it may never be as cool as some of yours, but this is the most work I've done to it in the last 7 yrs. Before this, it was on the ground as well as the planter boxes. After I broke my foot and had knee surgery, the wife suggested raising it off the ground. It's main purpose was to ferry produce from the veggie beds back to the greenhouse for washing.


----------



## CliffyJ (Apr 29, 2009)

Thanks HH, yes, that was the main one. 

Mike, what you're doing is outside of my experience. Out there. Totally cool. And I can't think of why it shouldn't / couldn't work. It looks like you're having fun!


----------



## Homo Habilis (Jul 29, 2011)

Mike:

Have you searched for terms like "xps insulation uv stabilized" with regards to the "... green powdery dust ..."? It appears to be an expected result due to unprotected sunlight exposure. 

Have a look at this link and do a find on "UV" - xps design considerations for extruded polystyrene roof insulation. You will see, for example - 

"XPS stored outdoors and uncovered for a long period may experience color fade due to UV exposure and potential surface “dusting” if exposed to UV for extended periods - generally beyond six months depending on the severity of sun exposure in a given locale. "​
By the way, I just Gooled - "site:mylargescale.com foamboard winn" to come up with the link to Winn's thread.

Hope this helps.


----------



## Mike Flea (Apr 8, 2014)

Thanks HH!


----------



## rntfrmme (May 23, 2013)

Interesting use of a limited space. High enough to make it easy to work on too. I like the tunnel and mountain to break up the sight lines....

Bill


----------



## Mike Flea (Apr 8, 2014)

Thanks Bill


----------



## Mike Flea (Apr 8, 2014)

got parts of the second mountain glued up today, will get pics after I get the top piece glued on.


----------



## placitassteam (Jan 2, 2008)

Mike this may be of some interest to you. My method probably won't help you but some of the techniques might. My cliffs were formed using chicken wire and hardware cloth (1/2 inch wire mesh) strung on rebar and backed up with tar paper and back filled with dirt. Here is what I have showing the build up.



























I then stuccoed the whole mess using a brown coat with some color added followed by several colors of color coat. I then detailed it with concrete stain. Here is the final product.









In your case I would paint the foam with stucco bonding agent, then use a brown coat with bonding agent added and finish with various color coats also mixed with bonding agent. One bonding agent to 3 parts water seems to work well. Looking forward to seeing your progress.


----------



## Mike Flea (Apr 8, 2014)

My only concern would be how heavy is the stucco once it's applied to the foam, I'm on a raised layout. If it's something I can apply with a paintbrush as opposed to a trowel, then I can make the coat thin. I'll try a small batch and test it out.

I looked up the bonding agent from the local Home Depot, I didn't realize it was a liquid, and at the bottom of the page was a picture of pre-mix stucco patch. There was also Flexcoat which is a foamboard coating, 2gal for $48, which in itself is cheaper than the foamcoat from Hot Wire or Rosco.


----------



## Gary Woolard (Jan 2, 2008)

Mike, perhaps you've seen a vendor named (if memory serves?) HOT WIRE FOAM FACTORY. They sell foam cutters, foam, and a couple different coating agents.

I saw a demo at a Big Train Show one year -- One of those agents is designed for exterior environments, and does indeed paint on like a very thin coat of Stucco . I think their product may be a bit expensive for projects as large as mountains -- but it is sort of 'proof of concept', right?

best,


----------



## Mike Flea (Apr 8, 2014)

Ya Gary, I've got a Hot Wire foam cutter and it does work well, better than using a hacksaw blade and wire brush and a whole lot neater. The price of their foamcoat didn't seem that bad, but when you factor in shipping, it would be easier and cheaper just to buy the construction grade Flexcoat from Home Depot, than to have theirs sent from California. The Flexcoat appears to come in 6 different colors, and is acrylic.


----------



## placitassteam (Jan 2, 2008)

The stucco I use on my buildings ends up very thin, no more than 1/8 of an inch. For a fine texture I use tile grout mixed with the stucco bonding agent. I put the brown coat and the color coat on with a paint brush. The brown coat I use is a commercial mix that comes in a 40 pound bag and has the acrylic already in it. I got it from a commercial stucco supplier, don't remember the price. I have used it for 3 large buildings and still have half a bag. I don't think weight is a problem if you do it this way. My Alvarado hotel is 8 1/2 feet long, 4 1/2 feet wide and 2 1/2 feet high and I could carry the whole thing except it is too big to handle!


----------



## Mike Flea (Apr 8, 2014)

Thanks Winn, and I saw your thread on the buildings, and they are very well done. You're an excellent craftsman.


----------



## Mike Flea (Apr 8, 2014)

the start of mountain #2


----------



## Mike Flea (Apr 8, 2014)

Twin Peaks Mine coming along....


----------



## Mike Flea (Apr 8, 2014)

Applied the first layer of Flexcoat today to mountain #2. Did this one first because I wanted to get the coating on before it started to decompose like the first mountain. I may do that one tomorrow depending on the weather and temp, but the powdery residue has to be cleaned off first.

This stuff comes pre-mixed, and it has a consistency of watery mortar. It looks like mortar, brushes on like paint, and when it dries, it's flexible like rubber. Since it has dried, I see a few spots that I missed, so I'll need to apply a thin second coat.


----------



## Mike Flea (Apr 8, 2014)

The weather here has been hot, humid, sticky, and when it hasn't been that, we've been getting heavy rains, since the last time I posted. Temps cooled off today, so I'll be able to get back to coating the other mountain. Oops, change that, the wife wants to make a couple of terrain changes, before I coat it.


----------



## Mike Flea (Apr 8, 2014)

Finally got the second mountain coated, still have to touch up and add second coat, as well as touch up first mountain, found more exposed areas today. Also still have to paint the inside of second mountain black. 

Threw in a pic of a light house bird feeder that I picked up from Menards. had an old broken K-Line revolving beacon, that I scavenged some parts off, manly the tower, fit right up inside the feeder, added a light, and Emmett Kelly and viola(sp).


----------



## Mike Flea (Apr 8, 2014)

Gaaaaaaaah!! the squirrels are using my mine for a winter stash! (top hole)


----------



## Mike Flea (Apr 8, 2014)

Little update, over the last year, through the winter and the heat of summer, the astro turf that was on the layout deteriorated terribly, so this year I tore it all off, except what was under the mountain at the far end. Also, some of the benchwork had started to sag to the point where the tracks kept coming apart, even with splitjaw joiners.

The greenhouse that the track originally went around had become a storage, and the poly tarp that was on it had also deteriorated, so we took it down, and cleaned up the veggie garden area. With all that freed up extra space, the wife suggested that we expand the railroad a bit, as well as leave an opening to the AC unit, should it need repair in the future.

So with the cooler weather we had here over the weekend, (50 -60 degrees), I went out and bought some plywood and 2x4's. We reinforced some of the existing benchwork, but also added 104 square feet of new benchwork. I'll get some pics up later in the week.

The track along the fence line will pretty much remain the same coming from the mine, and I'll figure out the rest of the layout over next weekend, with more pics to follow after that.


----------



## DennisB (Jan 2, 2008)

You can use the Weller soldering gun. There are screws that hold the wire in place. You can replace it with any shaped wire you would like. There are enough used ones for sale for about $20. This will save you a great deal. Many of the HO & N scale hobbyists use the Weller or similar type of soldering gun that has screws that hold the solder wire sin place. Regards, Dennis.


----------



## Mike Flea (Apr 8, 2014)

DennisB said:


> You can use the Weller soldering gun. There are screws that hold the wire in place. You can replace it with any shaped wire you would like. There are enough used ones for sale for about $20. This will save you a great deal. Many of the HO & N scale hobbyists use the Weller or similar type of soldering gun that has screws that hold the solder wire sin place. Regards, Dennis.


I'm sorry Dennis, but I don't know what you're talking about. I re-read through this thread, and there was no mention of a weller soldering iron anywhere.


----------



## Mike Flea (Apr 8, 2014)

Some new pics of the added benchwork:


----------



## Mike Flea (Apr 8, 2014)

Happy Thanksgiving to All !!


----------



## CliffyJ (Apr 29, 2009)

Hi Mike, a belated congrats on your progress!

I think Dennis was talking about converting a Weller soldering gun to a hot-wire cutter, by discarding the Weller wire tip and inserting your own (much bigger) cutting wire. Is that right Dennis? Interesting idea, if so... I have an ol' Weller to try it out on...

[edit, just found these] 
http://www.instructables.com/id/Foam-cutter-from-soldering-iron/















Whatcha gonna put on your particle board? Just curious.

Cliff


----------



## Mike Flea (Apr 8, 2014)

Ahh, That is a good idea, but I bought the Hot Knife brand of cutters, both the hoop and 4" knife, they both work good, but the hoop actually works better, it's a thinner wire. The thicker wire of the knife gets gummed up too easily, and is harder to clean off.


----------



## DennisB (Jan 2, 2008)

A number of the HO club members use the Weller type soldering. The screw that holds the wire in place is adjustable, so you can use a larger or smaller dia. wire. Dennis


----------



## Mike Flea (Apr 8, 2014)

Oddly enough Dennis, I have a very old Weller soldering gun, handed down from my Father, that I still use for light work. It has 2 light bulbs up front, perpendicular to where the wire goes into so you can see what you're doing.

On another note, I have purchased a couple foam cutters from Hot Wire, the knife, and the hoop, with the thin wire, which actually works better than the knife, and easier to clean.


----------

