I love the concept of the "Big Board," but wouldn't spend the $ on one. Nor do I really have room... So what I did was to get a 3/4" thick piece of wood from Lowe's (they will cut for you if needed, 1 cut free, I think 25 cents/cut after that), had it cut 2'x3'. I wanted to put it on top of a table I had purchased at Walmart, which was about 18" by 2', has X legs and is white plastic on top. Not big enough, but the next size is too big. I originally bought it as a work table, and had a portable Omni pressing mat on it, but didn't like the set up or size.
Next, I took a 2"x1" and cut it into lengths that are about 1/2 the length of each of the 4 sides of the board. Putting the board on the floor, wrong side up if there is one, I centered the table upside down over it and drew a line at the outside edge of the table top. I nailed the cut pieces of 2"x1" at about the center of each side and end. This allows you to put the new board on top of the table, giving more room, while keeping the larger top stable.
I laid a piece of muslin (I use Robert Kaufman's, which I buy on sale) that is about 2" bigger all around than the wood, on the floor. Over that I centered a layer of Warm & Natural cotton batting, then a layer of Insulbright, also made by the Warm Co (it reflects heat) and a a couple more layers of batting. The layers are such at this point that they are upside down from what they will be on top of the board, and except for the muslin, are about 1" bigger than wood on each side. Lay the board over the layers and center. Bring muslin up and stretch over the wood; use a staple gun to attach to board; you want it to be quite taut.
I LOVE it! It's portable, so I take it to retreats or sew-ins that our guild has. Works like a charm and gives me a lot of extra room for ... stuff ... while still leaving room for pressing blocks. Or if it's cleared off, a pretty decent sized pressing surface. I haven't had any problems with the muslin stretching, maybe b/c I stapled it very tautly?
And, okay, I'm pretty proud that I did it myself rather than adding to DH's already too long list of things to be done :wink: