I carefully cut the foam so it fits tightly into my frame and then I drag out my plan and a marker. The first two boards I am going to make include the river boards and one plain board. Using the precut edges as a guide, I draw out my river, including marking the 45-degree angles on the edges. You don't have to get this step perfect except at the edges where it meets the frame. If your river seems to have wandered off course, just redraw the offending part. We're going to cover all of this up later.
It's useful to keep other terrain elements in mind when you include rivers and roads on your boards. If you're not careful, you can wind up with 'dead spaces' that you can't add loose terrain. In my Historicon layout, this won't be a problem because the river is central to the action and I'll have plenty of space, but because these are destined for my own collection after July, I want to make them as flexible as possible. You can see one of my loose hills above (and catch a sneak peek at what the boards will look like in the coming weeks), placed on the board to make sure there might be room for it in a later scenario and different layout.
To carve out my rivers for this project, I used a hot wire tool designed specifically for cutting foam sheeting. This is basically a wire attached to a handle that heats up when you plug in the tool. A craft knife would work just as well. With either tool, you want to angle your cuts to give the impression of a slope, again paying particular attention to the ends where the foam meets the frame to get the transition as neat as possible.
To add some interest to my river bank, I decided to add a small permanent hill. I simply cut out a rough shape with the hot wire, then placed the hill against the bank and carved a little more to make the join as smooth as possible.
Finally, I use a sanding block to remove all of the sharp edges and create a gentle slope. This is only the work of a few minutes, but it's messy so I recommend doing this in the garage or making sure you have a vacuum handy!
Now we have to glue everything down. I used Liquid Nails for this project, but a dozen other adhesives would work just as well. You don't have to cover the entire surface. The wooden frame will protect the outside edges and for our river boards, we are going to be gluing some texture that will add more stability to the exposed edges The glue will expand as you push it down against the wood. The pic below is from an older project (and used PVA glue - see, I told you almost any adhesive would work), but the process was the same.
Leave everything to dry overnight to ensure a solid bond. I think it took longer to write about this step than it actually did to do it! I finished all six boards in a couple of hours. In the next post, these things will start to look less like lumber and more like terrain!