Hi
I found a copy of HO Railroad From Start to Finish, the especially for beginners column from the early '90s, and am enjoying it immensly.
My question is: How well do foamcore based layouts hold up? Does anyone here have experience with this?
I'm thinking of using this for a small Z scale layout.
Thanks
Mike
I'm beginning to realize that aging is not for wimps
I used foam on a module to make the hilly scenery. I overcoated it with pre-mixed sheet rock mud. It developed lots of fine cracks and separated from the edge fascia. On a hot day, the cracks opened up larger. On a cold day, they sorta almost disappeared*. It took a lot of work and additional weight to clean that up. To be fair, I have NOT heard of this happening to anyone else. But, hey, it happened to me.
I won't be using foam again. And I especially recommend not using it to support trackwork. Every foam based module I've seen has had the foam shrink down and cause dips where it meets the wood ends (as in, the foam shrinks down maybe an eighth inch; and the ends don't).
There is talk that if you age your foam for six months, that all will be right. But I have heard of no one actually proving that.
Ed
*The foam I/we used is a closed-cell foam. Each little bubble is filled with a gas, likely regular atmosphere. When a confined gas is heated, it exerts pressure on its container. That container will expand to SOME extent. The combination of expansion of all these little bubbles will cause the foam to expand. Possibly enough to be a problem. Possibly not. And, when the temperature of the enclosed gases drops, so does the pressure. And the foam shrinks back down.
This is in addition to the possible/probable shrinkage over time.
My entire layout is foam 110 sq, ft..All of it used,before I found it. The first table is 15yrs old, been moved twice.[no telling just how old that foam is] no issues.
the only cracks I have is where I did not tape before mudding,and they are simple to fix or hide
IMO. all this anti foam stuff is a lot like a political poll. The results are predictable by the questions asked
UNCLEBUTCH IMO. all this anti foam stuff is a lot like a political poll. The results are predictable by the questions asked
So. All the "anti foam stuff" is a lot like a political poll. Funny that all the "pro foam stuff" isn't. Or am I detecting the start of invective hurling?
I described what I experienced and what I saw. Others may experience and see things differently.
A person could do a search for "foam board insulation shrinkage" and see what comes up. Unless that's too much like a political poll.
7j43k used closed-cell foam. RR_ Mel and UNCLEBUTCH probably use high density foam.
There is also the cheap beaded form (packing material) which is structually weak and messy to shape but sometimes used to build up mountains and works when fully supported.
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
The foam I used was the pink/blue foam board insulation. And it's closed-cell.
The foam they used on this model railroader project layout was foamcore board, and they used it instead of lumber. That's the stuff I'm wondering how it holds up. I'm thinking for a 2' x 4' layout it might have half a chance.
----
All I want is a sleepy little branch line with two or three dozen trains a day.
I have seen the shrinkage of the blue/pink foam on modules, too. Where a great glue was used (Gorilla Glue or similar), the shrinkage has actually caused the wood it was glued to to bow. With white glue, the glue joint broke.
As best I can figure from the Dow and Corning literature, the shrinkage is real - as much as 1/4" over 8ft. It is caused by off-gassing after manufacture (similar to the plastic off-gassing in our cars that gives that new car smell).
Not all extruded foam modules suffer. The off-gassing seems to be concentrated in the first six months or so after manufacture, and decreases with time. So if the foam used has been sitting around for a while, it probably won't shrink any more.
Don't choose your foam from the new pallet that just arrived at your favorite big box store. And if you can, buy the foam in advance and let it sit for a few months.
Foamcore is a totally different material with a different set of problems. The commonly available foamcore in the US has had repeated problems with the paper surface wrinkling in the presence of water (water-based paint and scenery). Not everybody, and not in all cases, but enough to make it a problem.
In Austrailia, they don't seem to have the problem of surface wrinkling of the foamcore. and foamcore is often used for layout construction of lightweight show layout modules and sections. Sometimes, wood and metal wear strips are added to prevent denting. But for the most part, the foamcore does much better than one would expect through handling and transport.
just my experiences
Fred W
Hello all,
Please understand there is a difference between foam core and extruded foam.
Foam core is typically 1/4-inch thick. The foam is sandwiched between glossy matt paper.
This is typically used to mount photographs and as backing in picture framing.
It can be used as a modeling material but is typically used to make structures not as a base for a layout.
If you were to use foam core as a base I would suspect that the sub-base would either need to be a thick plywood or the open grid would need to be, at a maximum, 12-inchs on center.
The weight of the sub-structure would out weight (literally) any advantage of using foam core.
Extruded foam is used as insulation in buildings. It comes in different dimensions and thicknesses.
Most commonly it is colored pink or blue.
It can be sheathed on one or both sides with metallic foil.
This is what most modelers use as a base for their pikes.
My pike is 1-inch extruded foam board over 1/4-inch plywood on an open grid made of 1"x4"s.
The plywood provides the needed support between the open grid spacing of 32"x48".
Some of my features are layered 1-inch extruded foam. Each layer is bonded with yellow carpenters glue.
The foam is then sculpted by various means to achieve the desired result.
I have "sealed" the foam with latex paint. Then I senic over this.
We live in an extremely low humidity environment and I have see no perceptible signs of shrinkage in the three years my layout has been in existence.
Hope this helps.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
Ken Patterson made a "whats neat" video where he showed evidence of foam shrinkage. I too have seen this with my own eyes. My modular club has dozens of modules where the foam has started to contract (noticeable as cracks forming at the plywood/foam boundary/visible humps at the module ends. Foam is not uniformly even, and I found myself doing a lot of patching before laying track on my home layout to level the transition between foam sheets.
There is some confusion here. I believe that the layout the Original Poster (OP) is describing was indeed built with foamcore (before being gathered into a book, the series started in Model Railroader magazine in January 1991).
Foamcore is a paper-covered foam sheet. It's decidedly not the pink or blue extruded foam often used for model railroading that some posters are referencing. For the layout in the articles, Jim Kelly purchased special-ordered ½" thick foamcore – it’s more typically available in ¼" or 3/16" thick sizes.
With water-based paints and adhesives, there is probably some smal risk that the paper could become delaminated from the foam. If the OP is planning a small overall layout that needs to be especially lightweight, it might be worth considering. But as others have pointed out, newer materials (e.g. gatorboard) may be more satisfactory.
Other than a couple of small and temporary portable layouts, I haven’t seen any constructed of foamcore in the intervening 26 years. And never any where the support structure (the “legs”) were made of foamcore.
Byron
Layout Design GalleryLayout Design Special Interest Group
MikeWheeler The foam they used on this model railroader project layout was foamcore board, and they used it instead of lumber. That's the stuff I'm wondering how it holds up. I'm thinking for a 2' x 4' layout it might have half a chance. Mike
I apologize for not reading the thread more thoroughly and getting off track with extruded foam.
Foamcore has been/is successfully used for small layouts (generally around 2ft x 4ft) and modules. One of the experts in using foamcore for layout construction is Prof Klyzlr. His Brooklyn 3AM and Chicago Fork layouts toured and are famous examples.
The warping and paper wrinkling with water-based paint and glue are problems that have been encountered using foamcore commonly available in the US. Our Aussie friends don't seem to have the problem. Their foamcore seems to have a better quality paper coating. It might be worthwhile to make sure you get boards that have a clay paper coating.
Here are some links about using foamcore in layout construction:
http://smallmr.com/wordpress/working-with-foam-core/
http://make.berkeley.edu/wp-content/uploads/2016/01/Foamcore_construction.pdf
http://www.zelmeroz.com/album_model/members/klyzlr/Camp4.pdf
http://model-railroad-hobbyist.com/node/6338?page=7
hope this helps
7j43k I used foam on a module to make the hilly scenery. I overcoated it with pre-mixed sheet rock mud. It developed lots of fine cracks and separated from the edge fascia. On a hot day, the cracks opened up larger. On a cold day, they sorta almost disappeared*. It took a lot of work and additional weight to clean that up. To be fair, I have NOT heard of this happening to anyone else. But, hey, it happened to me. I won't be using foam again. And I especially recommend not using it to support trackwork. Every foam based module I've seen has had the foam shrink down and cause dips where it meets the wood ends (as in, the foam shrinks down maybe an eighth inch; and the ends don't). There is talk that if you age your foam for six months, that all will be right. But I have heard of no one actually proving that. Ed *The foam I/we used is a closed-cell foam. Each little bubble is filled with a gas, likely regular atmosphere. When a confined gas is heated, it exerts pressure on its container. That container will expand to SOME extent. The combination of expansion of all these little bubbles will cause the foam to expand. Possibly enough to be a problem. Possibly not. And, when the temperature of the enclosed gases drops, so does the pressure. And the foam shrinks back down. This is in addition to the possible/probable shrinkage over time.
rrebell 7j43k I used foam on a module to make the hilly scenery. I overcoated it with pre-mixed sheet rock mud. It developed lots of fine cracks and separated from the edge fascia. On a hot day, the cracks opened up larger. On a cold day, they sorta almost disappeared*. It took a lot of work and additional weight to clean that up. To be fair, I have NOT heard of this happening to anyone else. But, hey, it happened to me. I won't be using foam again. And I especially recommend not using it to support trackwork. Every foam based module I've seen has had the foam shrink down and cause dips where it meets the wood ends (as in, the foam shrinks down maybe an eighth inch; and the ends don't). There is talk that if you age your foam for six months, that all will be right. But I have heard of no one actually proving that. Ed *The foam I/we used is a closed-cell foam. Each little bubble is filled with a gas, likely regular atmosphere. When a confined gas is heated, it exerts pressure on its container. That container will expand to SOME extent. The combination of expansion of all these little bubbles will cause the foam to expand. Possibly enough to be a problem. Possibly not. And, when the temperature of the enclosed gases drops, so does the pressure. And the foam shrinks back down. This is in addition to the possible/probable shrinkage over time. First off there are different types of foam,
First off there are different types of foam,
I know. And, as I said, I used foam board insulation. As opposed to other foams.
second the foam has to be older or you have to let it sit for around three months or it will shrink because of off gasing.
Funny, I heard six months. I've heard LOTS of opinions on how long you have to wait until the foam stops shrinking. But it's all been anecdotal. I looked at a foam based module three weeks ago, and it's my impression that it kept shrinking long after six months. Another anecdote.
No facts based on experiment and research.
I have used the beaded foam covered with plaster cloth, no problems, no shrink.
That's great. That's not what happened to me. I would have preferred that it didn't, because I had to fix it.