A 1:20.3 scale street lamp post
Bill of materials
• One 12-inch stick, 1/4-inch square K&S brass tube.
• One 12-inch stick, 7/32-inch square K&S brass tube.
• One 12-inch stick, 3/16-inch square K&S brass tube.
• One 36-inch stick, 5/32-inch square K&S brass C-channel.
• One chrome-plated drawer-pull backplate (Amerock BP30361-26).
• Two strands, 18-inches, 24-gauge solid copper wire, insulated.
• One warm-white, 3.3v, 10mm LED.
• One 330-ohm resistor.
• One bridge rectifier (at least 20 volts; at least 1 amp; Radio Shack 276-1152 works but is overkill).
• One, 18-inch length 20-gauge stranded copper wire (speaker wire).
• One piece 1 x 3 pine lumber, cut to 2¾ length.
• Eight pieces, one-inch each, 1/8-inch heat-shrink tubing.
• One piece, two-inches, 1/4-inch heat-shrink tubing.
• Solder, paste flux, silicon caulking, glue, staples, paint, masking tape.
Tools
• Mini-torch, butane.
• Files.
• Pliers (needle-nose and regular).
• Wire cutters.
• Soldering iron or gun.
• Drill (plus 1/4-inch standard bit and 1-inch spade bit).
• Emory cloth or sand paper.
• Rubber bands.
Instructions
• Cut the stick of 1/4-inch tubing in half, making two sticks of 6-inches each.
• Cut the stick of 7/32-inch tubing into thirds, making three sticks of four inches each (reserve two pieces for other lamp posts).
• Cut the stick of 3/16-inch tubing into half, making two sticks of 6-inches each (reserve one of the pieces for other lamp posts).
• Cut the stick of 5/32 C-channel into two one-inch segments, making a notch at the half-inch mark on each (reserve the rest for other lamp posts). These are the clips.
• Take the 3/16-inch tubing and make a 45-degree cut at 2-inches. Make a second 45-degree cut at 3-inches. You should be left with one 2-inch segment, one 3-inch segment and one 1-inch segment.
• Using emory or sanding paper, clean off a half-inch from the square-cut end of the 2-inch segment of 3/16-inch tubing; do the same with a half-inch of the 7/32-inch tubing.
• Cover the cleaned end of the 7/32-inch tubing with flux paste and insert it into the 1/4-inch tube. Heat the tubes at the junction with the mini-torch and when the brass changes color to orange, apply the solder to the 7/32-inch tube side, allowing the solder to be “sucked” into the joint.
• Cover the cleaned end of the 3/16-inch tubing with flux paste and insert it into the 7/32-inch tubing. Repeat the soldering process.
• Cool the joined tubes (run under tap water for a second and wipe dry).
• Clean off a half inch from the square-cut end of the 1-inch segment of 3/16-inch tubing with the sand or emory paper; cover it with flux paste and insert it into the chrome back plate. Heat both pieces with the mini-torch, adding solder to the edges completely around the tubing. Cool the joined items.
• Insert the heat-shrink tubing into the clips; insert those into the 45-degree angles.
• Fish the 24-gauge wire down from the backplate to the end of the 1/4-inch tube.
• Bend the first joint from the bottom of the post to a 90-degree angle. Clean the joint with emory or sanding paper; apply flux.
• Heat the joint on one side lightly and then heat some solder, dropping a glob of solder onto the joint. Heat the glob a little bit but not before it melts entirely. Test the joint (gently) to make sure it will hold. Excess heat here will melt the wire insulation, so this step requires finesse to create a solid joint that hasn’t melted the insulation.
• Flip the joint over and repeat.
• Bend the second joint, clean, flux and solder the same as the first joint.
• Go back and file off the excess solder from the two joints.
• Drill a 1/4-inch hole in the pine lumber; it should be on the center line, 1-inch from the back. Drill another 1/4-inch hole into the bottom of the lumber (I put two pieces of lumber together in a vise and drill a hole between them, meeting the previous 1/4-inch hole). Drill the one-inch hole with the spade bit, using the top-down 1/4-inch hole as a center point. Go to a depth of about 3/8-inch.
• Fish the wire through the lumber and force the bottom of the lamp post into the lumber. Square it off and add silicon caulk or glue on the top.
• Trim off the excess wire at the backplate. Note the polarity of the LED (I mark the short-legged side — the cathode, or negative side — with a felt-tip marker) and trim the LED leads to about a 1/4-inch. Solder the LED to the 24-gauge wires, using the heat-shrink tubing for insulation. Note the polarity of the wires.
• Trim the excess wires off the bottom of the post. Slip on segments of heat-shrink tubing to each wire. Note that the rectifier will have one lead marked positive (+), two leads with ambiguous markings (literally, the “~” mark) and one with no marking. The lead with no marking is wired to your LED’s short-legged (cathode, negative) side and the positive mark goes to your long-legged (anode, positive) side. Solder the wires accordingly and slip back the heat-shrink tubing and heat to insulate. Solder the resistor to either of your ambiguous leads and cover the lead and resistor with heat-shrink tubing and heat to insulate.
• The speaker wire gets a piece of heat-shrink tubing on each lead and then its soldered, one lead to the other ambiguous rectifier lead and the other to the resistor. The tubing should cover the leads and then place the larger piece of heat-shrink tubing over as much of the electronics as possible.
• Force the assembly down into the hole and using glue and staples, hold it in place. Cover the entire assembly with silicon caulk and make a smooth bottom on the base.
• Cover the baseplate and LED with masking tape and paint the entire lamp post.
• Once dry, remove the masking tape and place the LED in the plastic cap. Attach the cap to the baseplate with rubber bands and use silicon caulk to attach the cap to the baseplate.
• Connect lamp post to your garden lighting circuit. (See my thoughts on low-voltage garden electrical connections.)
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