Originally posted by ezdays
but they both have the less dense, beaded Styrofoam that kinda crumbles on the edges when you cut it.
My question is, does this crumbly foam cause problems, or is it OK to use it?
Don
I used the white beadboard for all the mountains on a 12 ft HO sectional module about 12 years ago and, beleive me, it will be the last time I use it

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After gluing it down, and letting it dry, I carved it to a rough shape with a utility knife, and then used a sureform and wood rasp to smooth it all down.
When I was finished, I and everything else in my 12 x 19 foot train room was coated with a static charged layer of white styrofoam beads

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It looked like a freak snowstorm had just blown in and I had to empty the vaccume cleaner 4 times to clean up the mess

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Even so, I could not get them all and they seemed to appear out of nowhere whenever I needed them around least, such as during scenery construction or when running trains and every time I cleaned up afterward, more of those cursed beads would show up in the vaccume cleaner

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When I moved to my house last year, prior to the new owners arriving, I cleaned out that (now empty) room one last time and I STILL managed to vaccume up about half a cup of those beads.

I would not be supprised if some of them managed to hitch a ride in my train boxes to take up residence in my new digs

Try to find the insullating type (we call it blueboard or pinkboard up here) and if you can't, then maybe you can get one of the building supply stores to order it for you.
Happy modeling and Cheers!
Terry