FNH mentioned this idea, and once I used it my mind began to spin with possibilities. I wanted to describe the process in detail on boardgamegeek, but thought I should create an instructible, and link to it.
So here is: How to use Adhesive Backed Floor Tiles with your Print & Play Board Games. Specifically to add some thickness and heft to playing pieces (sometimes called "bits" other times "chits", but I can't tell them apart). You could use spray adhesive and cardboard, but it's messier, more expensive and you have an empty can to throw away at the end. My way, you've just got a piece of wax paper, a bunch of little scraps, and some annoying white dust on your table.
Pictured are some of the expansion pieces from Gottard Zancani's beautiful "Space Infantry" which is a "free, solitaire game of squad-level combat in the future." You can download this game--no, you SHOULD download this game. You can get it at his website: http://zak965.it/spaceinfantry/index.html
Step 1: The Supplies - Adhesive Backed Floor Tiles
Step 2: How to Do This Isn't Really the Point of This Instructible.
I've cut out the artwork that I printed on Cardstock. I guess you could print on paper, but I didn't. I didn't have an entire page worth of art to mount, so I cut out all the empty white space, to conserve on tile. I've peeled back the wax paper backing, and placed the cardstock onto the back of the tile.
Placing Cardstock onto the Tile. Notice how I use my fingers, rather than just letting gravity pull the cardstock down.
I recommend pressing the artwork firmly onto to the adhesive. I'm actually only pretending to press it down in this picture, but I'm a really good actor, that's why it looks so realistic.
I let the wax paper flap back down over the artwork before I started the broad-stroke cutting. I think it was just because it was getting in my way before, and I wanted revenge.
Here's where we start the precision cutting. Try to plan your cuts, so you don't have to do a lot of long cuts. If you need to do long cuts, use a metal straight edge, and razor blades. You can borrow mine if you want, but don't put any gouges in my table. For short cuts scissors are way easier.
Step 3: Finished Bits (or Are They Chits?)
Well, in the time I've taken to create this Instructible, I could have played about 3 missions. But I did this for you, and if you appreciate the effort I put in, you will kindly keep your "Too much time on your hands" comments to yourself. I value my free-time, and work very hard to make sure I have more of it than you do.
Have fun. I think I'm going to make an entire set of Settlers of Catan out of this stuff. I think I can produce it all on about 10 sheets of paper. Color Prints are 8 cents, and the tile is 88 cents, so I'm up to about $9.60 for a game that usually costs $40.