Asbestos millboard is a reasonably strong fireproof material that can be sawed and drilled. It was used inside railroad passenger car and locomotive electrical lockers as electrically-insulating, fireproof material. Usually the electrical panel was made of thick asbestos millboard, with relays, fuse holders, regulators, etc bolted to it.

Asbestos millboard was also great for insulating around stoves etc, because it was stiff, rigid, would not pack down under vibration.

Asbestos millboard is no longer manufactured. What is used instead? I bought a sample of "High-temperature millboard", 1/2" thick, McMaster-Carr p/n 9362K15, but its really just a high-temp version of drywall plasterboard, and crumbles easily. It's nowhere near as strong as real asbestos millboard.

I'm looking for a stiff sturdy material, <=1/2" thick, that can be right next to the edge of a restaurant-grade propane gas stove (in Niles Canyon Railway's S.P. 1975 "All Day Lunch" car kitchen), and insulate well.

Any suggestions for a modern equivalent of asbestos millboard?

Thanks! - Doug Debs

Off the top of my head, I would suggest this :

http://www2.dupont.com/Energy_Solutions ... _Sheet.pdf

Dave

While we're at it, what material are we now using to line the covers of streetcar controllers, etc? It was a sort of thick asbestos felt originally, with not only fire resistant but also arc resistant fabric.

dave

Doug, cement board is still made using fibers other than asbestos. It is not real popular as it is heavy, hard to work, and expensive, but it is still out there. Check the USG web site. I believe they are one of the makers.

Dave, there are papers made with Nomex fibers which will replace the asbestos material used in K controller covers.

I've used HardiePlank fiber-cement siding on a mountain cabin I have; made by James Hardie Co. Weathers and holds paint really well. 10 years old now; looks almost new. Comes textured to look like wood, or smooth. Also comes in plank-sized stock or plywood sized sheets. Cut with a special circular saw blade. I don't know about the insulation value, but something like that might work for you.

Dave,

Some Glastic products commonly known in the electrical trade as red fiber board or GPO-3 for the NEMA designation, have been used in various applications I have seen. Glastic FHT 1800 comes to mind. These are UL / CSA approved products with varying degrees of arc, flame and dielectric strength. It comes in various thicknesses, 1/32" being very easy to bend to conform to the curve of controller covers, 1/16" may work as well but I haven't tried this myself, yet.

Regards,
Gord

Doug,

Fiber cement board is the safe(r) descendant of the asbestos-based board materials. As others have said, there are a variety of very cheap fiber cement siding products readily available in America, most of which are not much to look at up close, and I would never use any of them indoors. There are also premium products that look much better, are thicker, and of course, cost more. I have a sample of 3/4" "Slatescape" fiber cement countertop material in front of me that sounds exactly like the material you described in your post. It, and a number of other fiber cement board products are represented by a company called American Fiber Cement Corporation in Colorado, but I believe they are importers, and their products are actually made by European companies.

The Slatescape is machinable, but it is also hard and a bit brittle.

Check it out.

http://americanfibercement.com

Why not some garden-variety cement board that can be obtained at a home improvement store ?

Dave

I am just providing options. The material I mentioned has a smooth surface intended for countertop use and is thicker than regular FC board.

As to using garden-variety boards, they would be fine if the installation was completely concealed behind the oven, or behind another material such as tile, but the regular stuff has a lot of toothy texture that is not appropriate for a kitchen where it will be exposed and need cleaning. If it will be completely concealed, I'd recommend 1/2" tile backer board.

Many thanks for the most useful and informative advice on alternatives to asbestos millboard!

- Doug Debs

HardiePlank / HardieBoard was the subject of a class action lawsuit alleging various problems such as mold, mildew and early failure. It's been a real problem here in the Great North-WET.

http://consumer.halunenlaw.com/class-ac ... nt-siding/

Interesting, but like I said, mine is 10 years old, and still looks good. MUCH better than what I have that is real wood. Of course, even in our mountains at 4,000 ft, we are a lot dryer than the Northwest (where I'm headed tomorrow to visit my daughter in Snohomish). At my cabin, we usually get only 15 to 20" of rain per year, although the last couple have been less than 10." A few times a year we get one or two inches of snow, but is only lasts a day or two. CA state fire authorities essentially require any new construction in the urban/wildland interface or in the woods to be either stucco or fiber-cement siding.

PSRM built a new restroom building a few years ago that was stucco, but had wood fascia boards. The building inspector required us to cover them with fiber-cement. And, for a couple of hundred feet surrounding it, there is bare dirt.