I toyed with the idea of adding a picture of the mat drying . . . but that would be as exciting as watching grass grow.
Instead, here's the next step: I trimmed the edges of the mat that would touch the side boards. I actually did this with the open side, too, but it's far more important to trim these edges. Once you secure the board to the base, if there's any overlap the mat will be pushed up, and there's no way to get it down. Guess who found this out the hard way? So, a very close, tight cut to make sure there aren't going to be any ripples in the mat.
Then, I started attaching the side boards. I had previously cut them, with only one mishap due to me forgetting that a board has two ends (don't ask). Here's the lengths:
2 @ 49 1/2 inches
4 @ 24 inches
If you forget that the long sideboard is supposed to cover the ends of both smaller pieces, you end up with one at 48 3/4" . . . but I digress.
I initially attached the board to the base with a thin nail. I needed to drill out the holes where the screws would go, but it's way safer to drill both holes as one.
I used 2 1/2" screws, and put three on each short side, with five on each long side, plus one on the very ends to connect the side boards.
I had to take a break because Mrs. Workshop came home with the guppy. By the time I made it back to the project, it was dark. But that wouldn't stop me! Almost there!
I sanded the rough areas of the furring strips, along with taking off the corners that could give splinters. I'll hit the boards with the shop vac later to pick up the sawdust.
And here's the final product. Sixteen square feet of battle-ready goodness.
What I learned:
1) I probably didn't need 5/8" particle board. It's pretty heavy.
2) Patience is good. I got lucky in finding the mat at 40% off. But, if I had a little more patience I wouldn't have made the wrong cut. Plus, I could have been a little better with the drill.
3) Find good stopping points, because your wife will invariably come home in the middle of you handling the drill and want your help unloading the car.
What's next? Trees and hills. And felt rivers.