Why would that be? They are both polystyrene, and both will burn, as will plywood. However, I would ensure adequate ventilation if cutting with a hot wire as both will fume somewhat when melted. Now it would be a bad idea to heat polyurethane foam, which is usually tan and is often covered with metal foil. It is a thermosetting resin, and thus it won't melt when heated-it decomposes and can give off cyanide fumes.
In building Ntrak modules I have settled on an outer frame of 1X4's with intermediate supports [6' from each end and every 12" in between] of 1X2's. The top is 1/4" underlayment plywood [aka luan plywood] to build the basic module. This results in a module that is fairly lightweight but rigid enough to absorb the shocks of transport as well as set up and tear down. All scenery is done with the blue or pink foam material. We did have some modules built with track mounted on foam but found the noise to be objectionable.
The blue colored Dow StyroFoam (brand) and the pink colored Dow Corning FoamulaR (brand) do in fact give of noxious fumes when cut using a hot knife; as shown below: The fumes still occur... but not as noticable with the hot wire cutters, as shown below: The white beaded foam board actually give off less fumes than the other two. The white beaded foam board is likely more flamable in that it melts very easily... probably due to more air entrapped between the beads. The blue and pink boards are my choice for projects despite the fumes. Definately cut them in a WELL ventilated area. Having said that... I didn't cut mine in a well ventilated area, using a HOT KNIFE and virtually choked on the fumes. It took a long time for the noxious vapors to disipate. CUT FOAM OUTSIDE YOUR LIVING QUARTERS! This has been a public service announcement.
I just use a small razor saw that has a 2-inch deep blade. I have to special order the 2-inch stuff, so I typically just use layers of one-inch. I've even just that with a No 11 Exacto blade. It goes nearly through, and I just snap the rest. I had a cheap hot wire cutter and hated it.
How does the "white stuff" hold up as a scenery base? Perhaps with a coating of plaster? Not used for carving. Has anybody used it as such?
I've used the one inch white foam on the JJJ&E and it has held up well for over seven years. Woodland Scenics makes this foam in 12x24x1" sheets. It cuts very easily with a wire foam cutter and can be carved without difficulty. Stay cool and run steam......
First, pardon me for my foot-in-mouth use of the term "styrofoam". Like many people, I use the term generically to refer to white beaded foam. I stand corrected on terminology. Owens Corning produces expanded polystyrene insulation panels (Foamular) in several thicknesses. Here is their data sheet: http://secure.owenscorning.net/Portal/uploads/document/20060127/58307-B.pdf Please note that OC lists the product as flammable IF exposed to suficient heat AND intensity (read: "open flames"!) The product contains a "flame-retardant additive to inhibit ignition from small fire sources". Take away the flame, the fire goes out. Dow Chemical makes the "blue" foam. Here is an excerpt relating to their foam products: Product Overview Dow Chemical's "Styrofoam" brand name encompasses a wide range of polystyrene-based insulation products. Included in our testing were two versions, the common white "expanded" product and the "extruded" Styrofoam Square Edge (see photo). Styrofoam (expanded)- This is the product most people think of when they hear "Styrofoam". It is white in color and comprised of thousands of individual "beads" which are pressed together. The most common use is as a cushioning material in shipping and packaging. Although it is not intended for use as an insulation, it frequently is. Most people have seen cheap coolers and ice chests made from it. As an insulation, expanded Styrofoam has many qualities which count against it. At R 3.84 per inch, the product is simply not a very good insulator. Secondly, it is very hygroscopicity (absorbs and holds moisture). This tendency to get, and stay wet, makes it something to definitely avoid when looking at ice box insulation. Styrofoam Square Edge (extruded) - This product is often called "blueboard" due to its light blue color. In spite of its relatively modest "R" value (4.92 per inch), Styrofoam SM is our overwhelming recommendation for foam ice box insulation in marine applications. Unlike its expanded cousin (above)and virtually all other foam insulation, Styrofoam "Square Edge" is completely impervious to moisture. This is a huge plus. While many other foams start out as better insulators, they inevitably suffer significant decline as they absorb moisture from the surrounding air. This is not the case with Styrofoam SP. Another benefit of its hydrophobic nature is that no "air gap" is required when installing it. This means that more insulation can be packed into a smaller space. If is available in many thicknesses and two sheet sizes. Even Dow "admits" that most people associate "styrofoam" with white beaded foam! (Me included!!) The Dow blueboard has properties similar to OC's pink insulation. It repels water, is very stable and it will NOT support combustion! It will burn AS LONG AS FLAMES ARE APPLIED. Otherwise, when the flame is removed, it self-extinguishes. As I did research on this answer, I ran across an interesting website describing the many varieties of foam products. If you're interested, here's the website: http://www.favonius.com/soaring/foams/foams.htm Aside from my "slip-of-the-lip" use of the term "styrofoam", I stand by my original assessments: blue and pink foam products are not hazardous in use. When cut with saws, they produce fine dust which is NOT known to be carcinogenic. When exposed to flames, they self-extinguish when the flame is removed. When cut with hot wire tools, they DO NOT product hazardous fumes, although the fumes they do product ARE noxious! (They smell REALLY, REALLY bad!) Model railroading is supposed to be fun, not dangerous! In model railroading uses, blue and pink foam boards are generally safe. That doesn't mean you should take NO precautions. Common sense would indicate using a dust mask when sawing, keeping open flames away and ventilating the room when hot wire cutting. Separate note to MK: I do try to keep my facts straight. I had great concerns prior to using foam on my layout. My research, which was much more intensive than what I am reporting here, indicated that white beaded foam produces the most hazardous fumes when exposed to fire, perhaps because of the formaldehyde used in the manufacturing process. Blue and pink foam appear to produce fumes that are noxious, not hazardous. That's my 2 cents worth. Blast away! Darrell, quiet...for now
nox·ious Pronunciation[nok-shuhs] adjective 1.harmful or injurious to health or physical well-being: noxious fumes.
Actually, the Foamular is extruded, not expanded. This is absolutely not true. The flame retardant resists ignition, but once ignited the foam burns with sufficient heat that it is self supporting. In fact, its rate of combustion can increase very rapidly. As it burns, it also melts and drips and splatters flaming liquid which can ignite anything else combustible that it lands on. This is why most building codes require a flame resistant barrier between the styrofoam and the building interior. Below is a piece that I lit with a Bic lighter. It took about 3 seconds to ignite with the lighter, and burned until it got too short to hold and I put it out.
Whoa, that's scary. If extruded foam were covered with latex or acrylic paint, would that serve as a somewhat effective flame-retardant barrier? I'm sure it wouldn't work in an inferno situation, but would it help against a small flame?
Note to myself: 1) Seal as much of the foamboard as possible with a non-combustable paint or plaster/hydrocal mix. 2) Make sure any wiring running though foamboard is properly sheathed and not nicked so-as to cause any sparks which could ignite the foamboard. Nelson, thanks for the product testing... I guess we can't take the manufacturer's comments as being totally correct with that example. I would imagine that they (DOW or OWENS CORNING) are not considering 'direct' flame being applied to the product as a means of combustability.
No, the manufacturers clearly state that the product is combustible and should be protected from sources of ignition. This is from the Foamular data sheet.: The Dow MSDS on Styrofoam is worded almost identical. I do not know where Darrell got the idea that it would not support combustion and would self extinguish, the manufacturers do not claim that.
I had an unexpected visitor to my layout party this week, the Fire Inspector, doing the annual smoke detector and fire extinguisher municipal compliance. I was not home at the time and he asked to see the utility room, when he saw all the Pink foam running around the furnace with track on it he promptly wrote us up and gave me 24 hours to remove it. When he came back the next day, he told me pink or foam insulation by code needs to be protected from a possible open flame 16 inches from the furnace. The fire code here means it needs to be covered with fire retardant drywall or Sheetrock.
WOW. Now there's a track work alteration that no prototype road has ever had to deal with! Hope you can get the layout adjusted without too much trouble. I guess it is good you found out. Did the Fire Inspector mention anything about any other combustible materials that had to be kept away, like wood??
Wood is flammable, but not necessarily combustible. New, fresh wood doesn't catch fire as easily as dried-out wood, which does combust.
Mark Yea was a little work. Check out my post in the Layout Party in the Layout design Forum. Interesting comment about other combustibles. The furnace is located in the back 3/4 of the utility room with the water heater. I would guess the distance from the wood studs to the furnace or water heater would be greater than 2 feet, so I guess that was not a problem. Other than furnace filters, there is not much in the room.
From Woodland Senics' FAQ: Why is SubTerrain Foam made with expanded (molded) polystyrene? Extruded polystyrene foam insulation board (sold in most lumberyards) can come with serious drawbacks. It emits low levels of toxic fumes when cut with a hot wire cutter. This should only be done with good ventilation. Many extruded polystyrene products also produce ozone-depleting chemicals when cut with a hot wire device. Woodland Scenics SubTerrain white foam does not emit hazardous fumes when cut with a hot wire cutter. Our foam is high-density, expanded polystyrene which is nontoxic and does not damage the ozone layer. http://www.woodlandscenics.com/Information/FAQ/faqsubterrain.html (Question #2)
. ...geepers ...creepers ??? I'm so confused over what to use for my layout base & scenery, that I'm turning the same shades as the various types of foam... What to do? What to do? Surely, somebody has a definitive answer. Right?? Ok... so where can you purchase the "white" foam, that's non toxic, etc. etc. etc.? What brand/type of foam does the "Tippi Hot Foam Cutter" use in his demonstrations? And where would one purchase it? Thanks !! .
