All five of the tray bottoms are now complete. They have not been mounted to the storage cabinets underneath or to each other. I need to build the backdrop and overhead lighting support system first. That will be attached to the back of the trays. The fronts of these trays will have 1/8-inch Masonite hardboard fascia panels installed later, which is why there is a slight difference between the edges of the trays and the edges of the storage cabinets. Eventually these surfaces will all match up.
The next step is to build the light bars. As my Layout Design page shows, I want to build an as-light-as-possible structure to hold the fluorescent light bulb above the module. The next set of photos describe how I built one of these. Some of this detailed construction is also for my own record, so that I'll know how I built one of these in the future. This first photo shows the parts on the table that went into building one of these light bars. The Masonite boards are 58 inches long for this particular module.
I glued 1/4-inch strips of Oak to one of the smaller Masonite boards so that there is more glue surface to which to glue the other smaller board.
Next I glued two pieces of 3/4-inch plywood as part of the end cap for the light bar. These provide structural integrity and allow me to attach side panels later on.
This is the basic structure of the light bar.
I cannibalized a standard 4-foot fluorescent light fixture for the two clips that hold the light bulb in place. Yes, those metal light fixtures are actually heavier than my light bar! I decided to glue them to the light bar, so I first needed to sand off the three nodules that are on the back. The one on the left has been sanded and the one on the right is the original. I used a grinder wheel, which made quick work of it. The clips are made of plastic, but it is a very tough plastic.
I glued the clips to another set of 3/4-inch plywood boards with epoxy glue and let them dry overnight. The clips are one inch away from the top of the light bar. The next day I glued the plywood boards to the light bar (shown here). Their distance from the ends are such that the light bulb, which is just slightly longer than 47 inches, comfortably fits between them. Some test fitting was necessary.
As mentioned on the Layout Design page, all of my layout wiring, which includes the lighting wires, will be above the light bar. I drilled two holes in the plywood boards and Masonite top and routed the wires out to the top. The ballast that will feed the light bulbs will be placed above also.
This photo shows how I routed the clip's wires above the clip to not interfere with the lightbulb.
The next step was to glue some more 1/4-inch strips for additional glue surfaces. I also glued two small Masonite cover plates at the end caps. These plates are on the bottom of the light bar, so they are visible.
And finally, the front fascia panel was glued to the light bar. The next photo is of the light bar completed and in its normal, upright position.
This is the bottom view. I hooked it up to one of the ballasts and it worked great. The 1/4-inch strips visible at the bottom of the light bar are there to provide support for the diffuser panel. A diffuser panel is needed to filter out the UV light which, over time, is said to fade our model structures.
This photo shows the back of the light bar. The wires sticking up above the light bar will be folded down and hidden behind the front fascia of the bar.
There is a 1-inch space behind the bottom trays of the modules and the wall. To make sure I would allow a bit of a fudge factor, I cut the vertical supports just short of 1 inch (15/16"). I am spacing them 6 inches apart (on center). In the next photo I am gluing the first set of these to the back of the light bar. The module's backdrop panel will be glued to these vertical strips of plywood. To balance these strips, I used paint cans and shims.
The backdrop panel is made of a 23-inch wide sheet of Masonite hardboard. The height was determined by how much space I wanted to leave between the top of the light bar and ceiling, since some wiring work will need to be done there. The sheet is being glued to the vertical supports. I used a bunch of mostly-full paint cans to provide the clamping force while the glue sets. The vertical strips of plywood wrapped a bit. That is fine for all but the one on the far right of this photo (not visible). I used a couple of finishing nails to force that one to be straight along the edge of the Masonite backdrop panel. This is because the right-hand side panel of the layout will be attached to this later. The point is that sometimes clamps cannot be used and so temporary finishing nails will do the job.
I bought two sheets of 2' by 4' styrene "clear cracked ice" ceiling diffuser panels. You can find these in the ceiling panel section of Lowe's or Home Depot. Make sure that the ones you get are not cracked, chipped, or broken, because they are rather flimsy. One thing to note: the panels are actually 47-3/4 inches long, not 48 inches.
The instructions on the sheet tell you to score the styrene, much like you would score opaque styrene used for scratch-building structures. I measured what I needed and lined up my straightedge. I scored the styrene a number of times. Then I lined it up on the edge of the table to snap the piece off. It went fine for about a foot and then the piece cracked. Crap! I took the broken off piece and tried cutting it on the table saw. It worked like a charm, and it left a nice, clean edge. I then cut the piece you see in the next photo using the table saw. It does leave a little bit of residue on the table saw blade because it melts some of the plastic while its cutting, but that comes off fairly easily.
Here's the back of the light bar and backdrop.
I then flipped the whole assembly upside-down on the table and put a second coat of white paint inside the light bar area. The idea behind painting the interior white, of course, is to reflect as much light back out the bottom of the light bar toward the layout.
Since this particular light bar/backdrop assembly is for the tray that is on the right-most side of the layout, I wanted to put a nice side panel against it. I needed some more glue surface along the edge of the front fascia panel at the top of the light bar, so I glued a piece of plywood to the top.
And here is the side panel cut to shape.
The next photo shows the drywall screws that hold the backdrop to the bottom tray. I added this photo mainly as a reminder to myself how I will need to disassemble these modules in the future.
To complete the hiding of the wiring of the module, I attached a barrier strip to the top of the light bar (behind the valance, of course). The two wires on the right (toward the back of the module) are for a 12-volt accessories line (for such things are lights and animation). The other two wires are for the DCC main bus wires. After this first module, I started using an 8-pin barrier strip so that the other pins could be used for routing the 110V electrical wires for the lights.
In the back of the module behind the bottom tray, another barrier strip was installed to route the wires from the strip at the top to the layout. This is necessary so that the wires can be removed when the layout is disassembled. In the photo I used connectors, but I soon stopped using them and simply screwed the wires under the screws of the barrier strips; much more reliable. After this first module I started gluing the barrier strip to the back of the Masonite backdrop panel instead of screwing them to the bottom tray, because bending those feeder wires so sharply was hard to do.
This shows an overall view of the back side of a module. You can see the fluorescent light ballast on top. All wiring from now on can be done at the top of the light bar.
Under the barrier strip at the bottom of the tray, I drilled holes to feed the wires to the front in the layout space. From there the wires will be routed and connected to things when the layout is being constructed. From the front of the layout, the wires on the left are the accessories wires, and the ones on the right are for the DCC bus (this is just for my personal notes). I also concluded it is much better to have these wires come into the module on either the left or right side, not in the center (a mistake I made in one of the modules).
Here is a photo of a couple of the modules finished and put in position.