A structure illuminated with ‘fluorescent light’

After completing a couple of “fire light” structures and placing them on the layout, I found the effect was getting a little monotonous and decided to do some change-ups. (See my thoughts on buying components.)

First, I bought a handful of “rural electrification” supplies from BridgeMasters of Placentia, Calif. (http://www.bridge-masters.com/), specifically the structure lamps, Nos. 303, 909 and 007. These I added to structures that didn’t have windows or open doors. I could have run these without their resistors, but added them to make the lights a little dimmer than they would normally be.

I also put a single LED in a couple of structures, using an amber lamp. This worked too. (See my thoughts on structures.)

But I needed something that looked dramatically different than the “fire light” structures and decided that fluorescent light had come to my community. (According to Wikipedia, fluorescent lamps were first available in 1904 and were being manufactured extensively by the late 1930s, which is the theoretical date of my layout’s community. In fact, I care more about the color of the light than the historical accuracy.)

When I bought the first flickering tea lights off of eBay, I chose blue ones on the theory I would be changing the LEDs anyway. Hence I had a handful of powerful, 5mm blue LEDs laying around following those experiments. (Subsequently, I bought 50 10mm blue LEDs, 60,000 mcds, from my supplier.)

I tried bundling three of the blue LEDs with a warm-white LED from those I had purchased for the lamp-posts. I wired them in series: leaving the positive leg of the first LED open and then connecting the negative leg to the positive leg of the second LED, the negative lead of the second LED to the positive leg of the third, the negative leg of the third to the positive leg of the fourth and then connecting the current to the negative leg of the fourth and the positive leg of the first.

Like the “fire light” structures, I decided to use the plastic canister to provide light refraction and reflection, which would be enhanced by painting the interior of the structure white. (See my thoughts on canisters.)

In my first couple attempts, I wrapped the LEDs around a one-quarter inch round dowel, using tie-wraps. Later, I figured out that a half-inch square piece of hardwood dowel, some cyanoacrylate (aka “Super Glue”) for short-term gluing and some silicon caulk for long-term placement would work better. I wrap the LED legs with electrician’s tape to make sure there’s no possibility of shorting out.

The key is to place the LEDs as far from the bottom of the canister as possible, so that they can refract/reflect off the top and down onto the sides. The half-inch square dowel is only two inches high, which gives it enough to be stable but still puts the tops of the LEDs about two inches away from the bottom of the canister.

Bill of materials
• One plastic canister.

• Three blue LEDs, 10mm.

• One warm-white LED, 10mm.

• One bridge rectifier (at least 10 volts; at least 1 amp; Radio Shack 276-1152 works but is overkill).

• One, 18-inch length 20-gauge stranded copper wire (speaker wire).

• Two pieces, one-inch each, 1/8-inch heat-shrink tubing.

• One piece doweling, half-inch square by two inches tall.

• One No. 4 pan-head, sheet metal screw, three-quarters inch.

• One fender washer, three-quarter inch diameter with hole small enough to contain No. 4 pan-head screw.

• Solder, paste flux, silicon caulking, cyanoacrylate, electricians’ tape, paint, masking tape, black permanent marker.

Tools
• Phillips screwdriver.

• Pliers (needle-nose and regular).

• Wire cutters.

• Soldering iron or gun.

• Drill (plus 1/32-inch standard bit).

Instructions
• Mark the negative legs on the LEDs with a black marker.

• Using the cyanoacrylate, glue an LED to each side of the square dowel, making certain that the negative legs are always facing in the same direction (I make them face right, so the black mark is always on the right). Apply the glue to the top of the dowel and don’t put any on the LEDs.

• After all four LEDs are attached to the dowel, place a good glob of silicon caulking in the center between all the LEDs, making sure it touches the dowel as well as the LEDs. Allow to dry (probably overnight).

• Gently pull the legs on the LEDs slightly forward and twist the negative leg of the first LED to the positive leg of the second LED. Repeat twice more, so that you have only the positive leg of the first LED and the negative leg of the fourth LED that haven’t been twisted together.

• Flux and solder the twists. Trim the excess of the soldered legs. Gently bend the joints back toward the dowel. Trim the two unsoldered LED legs to about one-half inch.

• Bend the positive and negative legs of the rectifier up over the top; trim the legs to about one-half inch. Making certain you have the correct polarity, connect the positive leg of the rectifier to the positive leg of the first LED by twisting the wires together. Then twist the negative leg of the fourth LED to the negative leg of the rectifier together. Solder both joints.

• Split the speaker wire into two strands for about two inches and strip the ends. Slip the heat-shrink tubing down to the end of the split. Twist each strand onto the remaining two legs of the rectifier (polarity here is not important) and solder the joints. Slip the heat-shrink tubing back up to over the joints and use the soldering iron/gun to heat the tubing until it shrinks tight over the joints.

• Using the electricians’ tape, wrap the LED legs and joints so they’re tight against the dowel. Wrap the rectifier so that it too is tight against the dowel.

• Drill a small hole in the top of the canister, and a same-sized hole in the center of the dowel. Slip the screw through the fender washer and the top of the canister and screw it into the dowel.

• Using the wire cutters, cut a small notch in the lip of the canister so the wire can come out; slip the canister onto its “top” (which is now the bottom).

• Add connectors to the other end of the speaker wire. (See my thoughts on low-voltage garden electrical connections.)

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