Apostrophe Game Store sells a 2-fold, blank hard-backed gameboard, with a matte finish and black covered backing, similar a RISK gameboard! Made with a glossy game board surface, it is suitable for markers and permanent ink. This bi-fold board opens to an 18” x 18” play surface. I found this one at Amazon for the great price of $10.98
This also comes in a 3-Pack of 20” x 20” folding boards for $24.90 from Amazon
This 3-pack is written up horribly on Amazon so, I am unclear if this is three thin bi-folds that butt up against each other to make a 20” square board or three 20” boards; and one of the pictures make it look like one quad-fold board, thought that could have been an image reused from the 18” board version. At that low cost 5hiugh, you can’t loose any way it comes!
"Every day when I wake up I don't let the old man in. My secret has been the same since 1959-staying busy. I never let the old man into the house." — Clint Eastwood