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© JANUARY 19, 2008  

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Building Search Light Signals

Completed signal installed on a scale railroad


Written by Robbie Diehl

If you have ever wondered what to do with all your old Audio and data CD’s this project is for you. I have made these Searchlight Signals using just that.

Each signal head requires two CD’s. The CD’s are glued together with PVC Cement. I glue them together face to face because paint does not stick to some of the labeling on the CD’s. After the CD’s are dry you center a piece of 3/4” PVC Pipe on the CD’s and draw a line with a marker to mark the new hole size. With a 7/32” drill bit make a "Swiss cheese pastern between the old CD center hole and the inside of the line. Using a Dremel Tool remove the remaining Plastic. A reamer could be used for this also. The hole does not have to perfect. The 3/4” pipe coupler will cover up the imperfections.

Parts required for making a Searchlight Signal.

Glue two CD's together useing PVC Cement

Cut 3/4" pipe couplings at 45 degree angle

Drill a 1" hole in top center of flower Pot and Side. Insert 3/4" metal Pipe Sweep and turn upside down to fill with concrete.

Use the 3/4” electric box cover for a template and drill two 7/32” holes in the CD to mount it to the electric box.  The 3/4” Pipe Coupler is inserted into a piece of scrap pipe and cut with a chop saw at a 45 degree angle to form the hood. A 1 1/2” long piece of 3/4” PVC pipe is also cut with the chop saw. Cut about a 1/4” off the end of the 3/4” pipe cap with a PVC pipe cutter. DO NOT USE THE CHOP SAW FOR THIS. Parts will fly everywhere. This cut does not have to be straight.

Insert the 1 1/2” long piece of 3/4” PVC pipe into the coupler. You can glue this if you want to but it is not necessary. Glue this to the front of the CD. Glue the 1/4” piece of the pipe cap on the back of the CD to help hold it all together.

You can cut a piece of picture frame glass into a circle and insert this between the coupler and the 1 1/2” long piece of 3/4” PVC pipe if you would like. I use LED’s for the light source and have found the glass is not necessary. The glass is very hard to cut into a circle also.

The Completed searchlight Signal Head.

The remaining pipe cap is used to hold the LED’s. I use Red, Green and Yellow. 4 small holes are drilled in the pipe cap for the LED leads. one for all the positive leads and one for each negative lead. You must use Super Bright LED’s. I use 5mm (15 Deg.): 6,800 mcd LED’s from Lighting Components LED Corp. Here is the Link to their Web site:

The signal Head can now be painted Black.

The base of the signal is made of concrete. I use an 8 inch Plastic flower pot for the concrete mold. A 1” hole is drilled in the center of the Flower pot and one on the side of the flower pot. Insert the 3/4” sweep through the side hole and then into the top hole.
Turn it upside down and fill with concrete.

Cut about 1/4" off end of pipe cap.

Enlarging the hole in the CD.

When the concrete is dry assemble the metal coupler and the 18” long 3/4” pipe to the electric box and the base. Put a pipe plug in the top of the electric box and paint this all silver or aluminum color. For a double headed signal add a 3/4” close nipple and another electric box signal Head.

If you build the 3 light signal head please note that this uses a 1” electric box all other Parts are the same.

Written by Robbie Diehl


Suggestion for making 1" round glass

Purchase 1 inch round mirrors from a craft store.  You can get 25 of them for a couple of bucks.  Remove the reflective backing by soaking them for ten minutes in acetone (be careful with this stuff and read the label).  Then take a razor blade and scrape the backing off.  It usually takes one swipe.  Then soak them in muriatic acid for about 30 minutes.  The acid loosens the reflective silver coating leaving you with a round clear piece of glass.  The glass fits right inside the pipe. Put a very small dab of silicone to hold it in.

Submitted by Jim Brown, Signal Superintendent, Maricopa Live Steamers 

Thanks to train web's signals page

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