Foamcore as a benchwork base

[Anonymous]

The foam "core" in foamcoare [;)] will not warp, but be careful of the paper coating! It will warp enough to bend the whole thing.... You are better off with the extruded foam, as many have pointed out. The expanded white stuff (sometimes called beadboard, of just styrofoam) has its uses in landscaping and so on. Just don't use it for "benchwork" as it is not nearly as strong as the pink or blue extruded foam.

Andrew

[Anonymous]

I am using 1/2" Foamcore as a roadbed material on my N-scale layout; I began using this when, as an apartment dweller, I needed a subroadbed I could cut without power tools and sawdust. The Foamcore just requires a straightedge and a good knife to cut. What I do is I elevate the foamcore above a solid tabletop; in one case I created a frame of 1x2's with a glued-and-screwed 1/8" Masonite top, then built up from there with foam. On my more permanent layout, though, I am rebuilding because of the insufficient 1/4" plywood I used as a poor high-school student. I am cutting out 1/2" Foamcore to lay down over this, and in some places I'm radically altering the track layout and gradients in the process. In both cases, it just takes a few foam risers every foot or so, and then I come back with expandable foam insulation (which comes in a spray can with a long nozzle) and fill in below, between the Foamcore and the tabletop or plywood. I use encyclopedias to weight down the Foamcore while this cures, because the expanding urethane foam will tend to lift it as it cures. This expandable foam is also what I use for scenic forms in general, so I rough these in at this stage as well. Once it has cured, I end up with solid foam beneath the rails.

I use AMI Instant Roadbed since it holds the track by adhesive action rather than nails or spikes, since the foam won't hold these. The end result is a lightweight roadbed which can tolerate some abuse (such as moving or being taken to train shows) and also tolerates thermal fluctuations (I currently occupy a relatively uninsulated third floor, where temperature swings can be the same as in an uninsulated garage), plus a scenic base that readily accepts tree planting. I also use a cellulose-based papier mache mixture for scenic sculpting, because it is also lightweight and flexible. The first layout I built this way is still operational, even after being stored in an outdoors metal shed for several years, and moving several times.

[orsonroy]

Don't use expanded foam, use extruded foam. It's strong, dimensionally stable, and doesn't require ANY support for really small (1'x4' ar so) layouts. It's easy to carve and is the way hundreds (if not thousands) of modelers are building their layouts these days. My current layout is a 3-level layout that's almost all 2" thick pink insulation board. The stuff's great. I'd only use Gatorfoam or foamcore for scenery elements like roads, sidewalks, and structures, mostly because of it's cost. And yes, extruded foam WILL dent, but that's a good thing. It means it won't always break! Pop an elbow onto my foam scenery, and I won't mind. A random depression is a good thing in scenery. Pop the same elbow onto a plaster and screenwire hillside, and you'll either have to fix the hole or try to outrun the layout owner!

As for the flammability comments, I'll keep it short. I keep seeing this WIVE'S TALE on this forum, and have replied to it in the past. Check the Dow-Corning MSDS safety sheets, as well as the fire rating reports from the University of Oklahoma. Extruded polystyrene has a higher fla***emperature than wood, and gives off the same sort of noxious fumes that the rest of your house catching fire would. You have more to worry about when your couch or carpeting catch fire than you do with foam on a layout. Don't play with gasoline on your foam layout, and you'll be fine.

[Anonymous]

QUOTE: Originally posted by davsachz

In the article the author used 1x2" or 1x3"s I believe and Expanded White foam 3/4 inch for his base.

No one uses expanded foam (the stuff used for foam party cups or foam coolers), it falls apart when cutting, sends off noxious fumes when carved with a hot knife and literally melts from the heat. Now extruded foam (usually pink or blue in nature) is much easier to work with, does not fall aprt when cut (makes clean up very easy compared to expanded), doesn't just melt away like expanded, but rather flows away from the knife and only while heat is applied. Unfortunatly, it also gives off bad fumes, so best to work in a well venilated area if you plan to hot knife/wire it.

The benifits are enourmous though, instead of a 3/4" thick piece of heavy plywood, you can use a 2" think extruded foam based that's far lighter. you can carve the foam to make gullies, chasms and other unique things that would be near impossible with plywood alone. the sound absorption of foam over plywood is imense, cutting sound down to a mear fraction of what it would be on plywood. you can put the track directly on the foam and carve out your roadbed more realistically (slight sloping of into a ditch on the sides of the rails). thus making your scenery more realistic.

Jay

[Jetrock]

I have heard of 1/8" foamcore (the kind with foam sandwiched between two sheets of paper) being used for mini layout bases (smaller than, say, 2x4 feet), especially in the form of two pieces of foamcore glued to each other for added stiffness) but it might not be practical for large applications and a border of some sort of wood or other ding-resistant material would help it resist dents and accidental thwacks.

[Anonymous]

QUOTE: Originally posted by jebgab

Dave,
My question deals with the combustibility of extruded plastic materials. From what I gather on the internet these materials are combustible and may give off toxic fumes. Any idea as to whether there is some way to lessen the combustibility?
John

Never thought about that aspect. I wouldn't want my MRR to kill me in my sleep.
Never had to worry about wood chicken wire and plaster :)
I'll check on the Mfg's site or pamphlets at the Home Depot. There must be some safety rating for it, especially if it's used as a home insulation. Some of the other foam is really made for Packing etc not for home use. Good question. Dave

[Anonymous]

Dave,
I do not have the answer to your question. The April, 2004 issue of Model RR has an article at page 46, by David Popp, entitled, "Step by Step-Landscaping with Foam". In the article Mr. Popp speaks to the virtues of using extruded polystyrene insulation board for a base for scenery. His column seems to indicate that he does what you are considering. I am also interested in what you propose for similar reasons. My question deals with the combustibility of extruded plastic materials. From what I gather on the internet these materials are combustible and may give off toxic fumes. Any idea as to whether there is some way to lessen the combustibility?
John

[Anonymous]

I read a recent article in "N" Scale magazine about ultralight benchwork for portable layouts. In the article the author used 1x2" or 1x3"s I believe and Expanded White foam 3/4 inch for his base. Has anyone on board tried such a thing ? I think I'm going with a shelf layout. Since I'm a photographer and familiar with Foamcore and better yet Gatorfoam I'm thinking of going this route. I know the plus's of Foamcore are it's very light and doesn't warp. But it will dent. Gatorfoam which is more expensive and come in 3/8" and 1/2" I think is similarly lightweight, won't dent comes in white or black but is not as readily available or as cheap as foamcore. This with a solid ladder frame and Blue or Pink Foam for scenery would be very light to work with. What do you think ? Thanks, Dave