I need some info on foam board:
How big is the foam board?
What kinds of foam board are there?
How do you cut/ mold foam board?
What tools will I need?
where can i buy it?
Typically 4x8 feet, sometimes 2 x 8 or 2 x4 feet.
You want to use only EXTRUDED foam board, not expanded. Most often extruded is blue or white.
Hot wire, hot knife, knife blade in sabre saw, hack saw blade, rasp, hand saw, etc.
tools - see above
Home Depot, Lowes, Menards, building centers, contractor wholesale…
I recommend getting the 2" thick stuff if available, in OKC I could only find 1/2", so I laminated it.
My hardware store carries 4x8 sheets in the following thicknesses:
1/2"
1"
1.5"
2"
2.5"
(The thin sheets are typically sealed in a plastic film that easily peels off.)
It is important to note that the Extruded I find is either Pink or Blue. The expanded is almost always WHITE. YOU DO NOT WHAT THE EXPANDED. Trust us.
Interesting, the most common size here in Canada is 24"x 96" ( 1/2" und up).
BTW the expanded foam (beadfoam) is terrific for making stone walls, tunnel portals and other such that needs texture!
my local 84 lumber has it in both 4 X 8 and 2 X 8 sheets of 2" thick. They use pink, but I don’t see that it’s a big difference from the blue. It’s extruded foam, and since it’s going to be covered by scenery, joint compound, paint, etc., it doesn’t matter what color it is.
Don’t buy the EXPANDED styrene, that’s the stuff foam peanuts are made up, the kind that breaks down into beads. EXTRUDED is what you want. It’s commonly sold as structural insulation board.
whats so bad with expanded foam board
cody…
The expanded foam board is little white balls. When you cut, manipulate, or sand it, the little suckers break free and multiply. Thanks to the inherit static cling of EVERYTHING and them, they get and go everywhere!!!
More importantly, expanded foam has no structural strength, doesn’t absorb shocks well, can’t be finely carved, and won’t support weight. Extruded foam does all of these things, and does them pretty well.
ORSONROY…
Excellent point. I completely left out these positives.
And those little bunnies WILL get into your engine right where it counts the most. I purchased some 4x8 sheets of Blue extruded foam (1/2 inch) which will be layered on a 6 foot section. That white peanut stuff dont even think about it. You can easily poke a finger thru them and such.
My next problem is a base for the 6 foot section however, am working on it (It will be less than 2 feet wide)
I am starting a layout now and this is my first experience with foam board. I am stacking the foam board for the base and terrain features and I used Liquid Nails for Projects and Foamboard, which worked in attaching it to the wood base, however on the instructions it says “Note: will not adhere foambaord to foamboard.” What should I use when I go verticle with this stuff? Will plain white Elmers do the trick? Any help would be appreciated.
White Elmers type glue works on most all foams, the secret is to give it enough time to dry and make sure its securely attached. Otherwise it comes apart very easy. If its stacked just weighting it down works well enough but if it sideways or at an angle use large push pins, the kind you can remove when dry, to secure the blocks.
The label on LN says that it won’t adhere foam to foam? That’s new. I used LN on my last layout, and had a 8’x8’x5’ high mountain, all glued together with LN, and didn’t have a problem. I read all sorts of labels loking for foam safe adhesives, and didn’t see that odd warning…
I now use Elmer’s wood glue, since the bond is as good as LN, and it’s cheaper (and available in 5 gallon buckets). You do have to weigh down the foam for a day or so, to make sure the glue “grabs” (bricks and bamboo shis-ke-bab skewers are good for this). It will also take up to a week for the wood glue to dry completely in the center of large sheets (of course, ANY latex or water based glue has this problem, including Liquid Nails)
A while back in the reader mail portion of model railroader, someone mentioned that when it burns, it gives off toxic fumes and was highly flammable. Does this make extruded foam a danger to use for layouts that will be indoors(in living space). I believe the letter was in reference to a home layout using brackets to attach to the wall. There was exposed extruded foam board along the wall(not covered with drywall)
I saw that letter too, and it caused a little bit of a stir on the Atlas forum. That forum’s search routine isn’t working right now, but I basically discovered that the writer of the letter was full of it.
Extruded foam insulation has been around for several years now, but it’s changed proberties several times as well. A cited MSDS safety sheet and a Canadian report on the hazards of burning foam were all published in the mid-1970s. It being the 2000’s now, I looked for newer info. I found the new Dow and Owens-Corning MSDS sheets online, as well as a university report on the burn properties of materials used in stock shed construction. The MSDS sheets reported that the flash point of foam was several hundred degrees ABOVE wood, and the university report reported that unpainted 1/2" drywall started to burn sooner than 2" foam, when direct flame was applied.
Foam will not readily burn. When it does, the entire house is basically engulfed, so you’ll have more pressing problems. Foam does emit toxic fumes when melting (that temperature is much lower than it’s burn point), but the released chemicals are no worse than the burning carpeting and cushy furniture that’s also on fire.
Unless your house is built of field stone, and there’s no open flames or electricity in it, there’s a chance it’s going to burn. take the same “common sense” precautions with your layout as you would with the rest of your house, an the “dangers” are minimized to normal.
People who think that foam layouts are deathtraps are misinformed or ignorant.
Orsonroy,
Thanks for your reply. I was hoping to see more info from model railroader after publishing that letter(and they may have printed more, but I didn’t see it). I am not to the point of starting my layout yet(room remodeling/layout planning/time),so it wasn’t that pressing of a concern, but it was a concern.
Jeff Coggins
No problem Jeff. And sorry if I came off as a little “angry” with my last post. I’ve heard a lot of interesting things concerning this issue, and most of the loudest opinions came from individuals who had no idea of what they were taking about. They’d rather spout off rather than actually study the issue.
Like I said, most of the safety reports are online. It only takes a little while to find several online, read all the different studies (not “opinions”), and base your own decisions from there.
One piece of logical thinking I have heard come from this discussion is that 2" foam with at least 1/4" of drywall compound on it is virtually unburnable. I don’t like using ANY plaster on my foam layouts, but it would seem to be a good compromise between the ease of foam layout construction and addressing fire safety issues.
Hello everyone! Thank you for your valuable input.
CmdrAntilles, thanks for starting this thread! Super good info from the respondents!
Some of them well thought out and detailed.
I didn’t even know that there was a difference among the above mentioned styrofoam materials. I was concerned about the mess as I had thought all these foams reacted the same way to heating, cutting and shaping.
I’ve been debating between homasote and styrofoam for my future layout. Based upon your input, I’m taking the “extruded” foam route.
As I’ve stated before this forum can be a priceless, helpful tool.
Thanks again. God Bless you all!
AFP45