I am currently working on a complete interior restoration of a rib side Milwaukee Road caboose. We have stripped the interior wood and the old insulation out so we could perform the repairs to the exterior metal without risk of starting a fire. I am going through different options of insulating the walls and ceiling. Has anybody used the spray on insulation that is used in houses? I am referring to the system where a contractor sprays it on and then trims it flush with the studs after the material has set up. I am looking for input regarding durability of the material itself. Has there been any cases where the material breaks down and settles to the bottom of the wall? Was it cost effective rather than cutting in styrafoam sheets to fit the cavities? Any input would be greatly appreciated.

Ed

I might think the spray on foam would make things very messy for the next time the piece is restored. A restoration using styrofoam sheets would be easy to reverse with no harm, years down the line.

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Will

Reversibility is an important factor in any "restoration" and that is probably enough of a reason to not use spray on insulation.

Aside from that, some of the spray on insulations are cellulose-based. I would check to see whether the product you are looking at absorbs and holds moisture or not. If it does, because of the environment a caboose is typically stored and operated in, you will likely have problems down the road with corrosion between the steel and insulation. And with other types of spray on foam such as urethane, it will be extremely difficult to remove "when" you need to do future carbody repairs.

It think you'd do best with rigid panel insulation, probably fiberglass as it is less combustible than the cheaper styrene-based foam boards.

Good luck with your project!

--Richard

Niles Canyon Railway has a Milwaukee Road steel plug-door reefer that was converted to an insulated boxcar with spray-on insulation (details below). When the spray-on insulation was removed, localized pitting corrosion was found on the steel sides. Apparently the spray-on insulation traps moisture, or traps moisture in areas where it doesn't adhere well. So probably this is not a good choice for long-term preservation.

Most insulating foams release incredibly toxic gasses when they burn, i.e. during car repairs using a cutting torch or grinder. Beware. A walnut-sized piece of urethane foam (standard seat cushion material), when lighted with a match, produces enough acrid choking fumes (cyanide compounds, IIRC) that will fill a large room in seconds. These fumes are deadly in house and sofa (i.e. cigarette butt) fires.

On the other hand, recently-built insulated boxcars and reefers use foam-in-place insulation because it fills all the nooks and crannies inside the walls, and doesn't tend to settle under the pounding and vibration of railroad service. It stays much more effective than insulator systems used during the steam era: fiberglass, cork, spun asbestors, curled horsehair, kapok, etc.

- Doug Debs

URT 29330 Refrigerator (Builder unknown), (Built date unknown)
40' / Steel, single plug door / (Weight unknown)
History: Union Refrigerator Transit Co. (URTX) #29330; (Subsidiary of the Chicago, Milwaukee, St. Paul & Pacific Railway); Modernized exterior insulation and renumbered URTX #29114; Acquired by PLA. Exterior insultation removed revealing Milwaukee paint. Painted while used as shop car for SP Pacific #2467 in Oakland, Moved to Niles Canyon in big move of Jan 8, 2005. Repainted and lettered for Milwaukee Road in 2007. In photo freight service while undergoing restoration, Brightside, CA.