ORIGINAL: fred985
check out your local lumber yard for 4 by 8 sheets of what we used to call beaver board. it is like ceiling tile but 1 inch thick. pinsd go right in and i have used this for years with no problemsd. in the north east,,curtis lumber has it.
Are you refering to the gray board called Homasote? It's used by train set builders because it is dense and resists warping. Comes in 4x8 sheets at the home centers or lumber yard. I've used it for bulletin boards for years in the office, paint it white and it's easy to find anything laying on it.