Construction Has Begun

Construction of Le Mars has begun. My plan is to start on 18″ shelf that contains the transload and IML Containers. Build that to a reasonable state of completion and, if I’m satisfied with this change in scale and prototype, then continue with the rest of Le Mars, working north. Below is a chronicle of the construction process. If it looks familiar, it probably is – I’m unashamedly copying the construction techniques (for the most part) of James McNab of The Hills Line fame, who was gracious enough to answer question after question on how he did things.

Benchwork

Since I was starting with the previous benchwork consisting of Ivar shelves, most of it was already in place. However, because I am using 2″ foam, I needed to add some more support for it. Along the back side of the 18″ transload/IML section, I ran a 3.5″ strip of the same plywood used for the front L-girders. This created a raised platform on which to attach the back edge of the foam.

Down the middle of that girder, in the center, I added a vertical piece of the same material. This helps support the flat piece to keep it from sagging, but also bridges the gap between sections, creating a very sturdy and strong T-support.

Finally, filler pieces were added on top of the girders attached to the Ivar shelves.

Foam

Next came time to cut the foam. A jig saw using a Bosch T118G blade worked well here. I know they make knife edge blades that are supposed to be ideal for cutting foam, but this one with tiny teeth worked just fine and produced only minimal dust and foam particles.

After test fitting the foam, it was time to install. A bead of Loctite PowerGrab All Purpose adhesive was spread on each contact surface and the foam placed on it.

At the joints between foam pieces, some adhesive caulk was used to seal the gap and keep the two pieces from moving independently.

After the adhesive cured, I came back with some general purpose flexible caulk and started to fill the cracks, large dents in the surface of the foam, and the score lines in these sheets of foam. This took several coats as the caulk shrinks when it dries.

After finishing the foam, layout lines for the eventual tracks were measured and drawn on the foam with a black Sharpie marker. Some track and turnouts were laid down to get an idea of how things will look.

Fascia

Next came the fasica. Since Home Depot was out of regular 1/8″ Masonite, I purchased some with a white coating. What I didn’t realize until I got home was that the white surface actually had a minor texture to it. This will making filling the holes and getting a consistent texture more difficult (more on that later). The board was cut into 6.75″ wide strips. These strips were attached using a screw about halfway up, but still in the wood support and not the 2″ foam. These holes were pre-drilled and countersunk so that the screw head would sit below the surface of the fascia. Some adhesive caulk was applied between the board and the foam in places (especially at the joint between fascia boards) to prevent flexing between the fascia board and the foam.

The screw holes were filled with drywall joint compound.

Once that was dry and lightly sanded, the rest of the board the skim coated with joint compound. This step was done to (hopefully) fill the texture that was present in the white coating of the board, producing a uniform smooth surface.

After sanding again, I wasn’t happy with the surface. It was still too inconsistent with noticeable texture and lumps where the screws were. Additional sanding took care of the lumps, but the skim coat didn’t really do what I had hoped since it was all sanded off. Next, I tried some filler primer.

Once the primer was well dry (4-5 hours later), I sanded it with a random orbit sander set on the lowest speed using 320 grit sandpaper. This produced a very nice, consistent surface finish, allowing me to apply the first coat of paint! The fascia and foam were both painted with Behr Wild Rice Semi-Gloss.

The fascia will need a second (or maybe third) coat, but this is certainly progress!