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Has anyone researched alternatives to extruded polystyrene or XPS Benchwork and roadbed
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Active Member 59 posts George Saridakis Active Member 59 posts
George Saridakis

I am in the early phase of ultra light sectional layout construction, and was planning to use square aluminum tubing framing, extruded polystyrene (XPS) risers & sub-roadbed, cork roadbed, and Bragdon resin based scenery to support the roadbed.

Light weight layout sections are a must because of back issues.

After reading Joe Fugate's recent article in Sep MRH (pg 143), I am looking for alternatives to big box store XPS sheets.

Has anyone researched dimensionally stable foam sheets?

Thanks,

George
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joef MRH Founder 18,651 posts
joef

Polyiso

There's a comment on the Reverse Running thread about polyiso foam ... It seems to be have better stats:

Quote:

According to a six-year industry study which concluded in February 2016, polyisocyanurate foam (polyiso) only shrank 0.0016% over the first two years (due to out-gassing), then stabilized. Multiple brands were tested (see sources in my earlier post). This stuff is great! You can spray-paint it (it's chemically-resistant), glue it, cut it with just a hobby knife, and shape it using just a fine-grit 3M sanding sponge.

Source ...

Quote:

One type of foam is polyisocyanurate ("polyiso"), sold under the brand,  RMax Thermasheath-3, at Home Depot.

Joe Fugate​
Publisher, Model Railroad Hobbyist magazine

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Prof_Klyzlr Moderator 8,263 posts
Prof_Klyzlr

Foamcore

Dear George It would take a change of structural thinking on the part of the layout builder, (more "build UP to level" than "carve away"), but Foamcore teamed with Qubelok aluminium framing can produce road-proven lightweight layouts and sections. Use MRH search at top right of this screen to find the details... Happy Modelling, Aim to Improve Prof Klyzlr
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YoHo Prolific poster 4,099 posts
YoHo

I think Polyiso was the

I think Polyiso was the product I used on my layout when I lived in San Diego. I liked the working properties of the material, but It seemed to have some sort of fibers in it that would basically get on your skin like Fiberglass insulation. Not as bad as fiberglass, but the same type of experience. 

 

 
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Metrolink Frequent poster 705 posts
Metrolink

I love polyiso!

I'm the guy that was blabbing about polyiso. XPS is a bit hard to come by in temperate climates, so that's how I ended up using polyiso. I haven't noticed any fiber-irritant at all—I've been working with bare-polyiso for weeks and it seems very benign. It has number of advantages over XPS. But it has one big disadvantage—it's covered with a thin sheet of paper-backed aluminum foil on both sides. You can pull it off, but it only comes off in tiny pieces. I just left mine on for my sub-roadbed, but pull it off for making rocks and stuff. It's great for everything you use XPS for, but unlike other foams, it takes spray-paint! It's chemically resistant so you can use any kind of adhesive (I use Liquid Nails for Projects). It's also super-easy to cut and shape. I don't think you can use a hot-wire since I believe it produces hydrogen cyanide gas if burned. But, other that that, I love this stuff!

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FCEN60 Active Member 39 posts
FCEN60

I looked up R max but my

I looked up R max but my Homedepot doesn't carry it here in FL. They do carry something called GAF energy guard Polyisocyanurate. Another place carries some Dow Thermax. So, I found a couple of more products with either the words polyisocyanurate or thermax in there name. Are all these the same stuff as the Rmax polyisocyanurate?

Joe
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