First of all I would like to thank Mark Kelley at Sigtronics for sending me some photos of the S58 Headset and answering questions I had.
The earmuff sections are made by first making an inside and outside form from balsa. I had picked up some block balsa, using the cad drawing I made, I started carving the blocks out to look like the head set. After carving I picked up my sandpaper and finished up the forms to look like the photo.
Then I used the press forming method (see my article) to make the parts from .015 plastic. I personal used clear, but you may also use white. You will see on each side of the form I have stacked balsa up. The trick is to have it just high enough that the press plate will set on top of the balsa and make a full form of the part. By doing this it will allow you to use the press plate as a guide to trim out the ear molds. Now that the part is formed do not remove it from the press plate yet. Now take a knife with the blade flat on top of the press plate trim out the part.
You will need two of each part to make a full headset. With ear molds now cut out take a section of balsa (1/16 to 3/32 thick) that will fit inside the ear molds and use this to glue them together with.
After you have glued the front and back together you will need to do some light sanding to remove any seams between the parts. I used Microballon in this are with thin Ca. When finished filling cracks lightly sand the parts to prep them for painting.
Next you will need to drill the 1/16 hole through for the pin along with the other holes need for the boom mic, cable, and the knob. Spray a light coat of gray primer on allows you to look for gaps between the parts. When happy with the parts, spray on a coat of paint. I used Sky Blue in the Wal-Mart brand of spray paint This is as close of a match I could find to the blue of Sigtronics.
To simulate the foam part of the earmuff, I purchased some 1/8-inch diameter black roping from a craft store. Apply a small line of thick CA and attach the roping to the inside of the earmuff. For the volume knob I made it from a section of 1/8 dowel rod. The headband is made from 3/16 by 1/64 thick brass stock. To determine the length of headset band measure from center of one ear over the top of pilot’s head to center of other ear then subtract 1.375 inches from this. This will be the length need for the headset band. The earmuff band is made from 3/16 by 1/64 thick brass stock. Cut to length and drill holes as noted on the drawing. ***Note that the end radius and the 1/16 hole do not use the same center point***. Bend parts as shown, sand them for painting.
With the parts assembled (line up the center hole in the earmuff band and the hole on the end of the head band) I use some silver solder and soldered the parts together. Now give them a coat of flat black paint. Allow paint to dry, and then install the small 0-80 screws through the holes. The pins holding the earmuff on are made from a round tooth pick sanded down to 1/16 in diameter and painted with silver paint. The little E clips (1/16) can be bought at most ACE hardware or Lowes stores. With the earmuffs now attached to the headband you will need to install the cross feed cable. I used some small electrical wire just under 1/16 diameter for the cross feed wire. I used some small strips of thin metal (metal part off of a floppy) cut to 3/32 widths to fasten the wire to the headband. Next use a section of foam rubber from an old mouse pad and make the headband pad. Cut it 5/16 wide and the length was cut to make it look proportional to the headband. The Sigtronics logo on the side is scaled down jpg and printed on clear label paper and applied to the headset.
To make the cable for the headset, take an old set of walkman headphones. Use the one that has two cords molded together. Now cut you a section about 14 inches long and pull all the wire out of the center, you want to keep the black rubber insulation part. This gives you the size of wire you need and by removing the wire inside makes it very flexible. Another option you could use is black leather cord from a craft store. You want to keep the diameter of the cord down around 1/16. Headset end is just glued into the headset. For the other end you can just tuck it in somewhere that will not be seen, but if you plan on terminating it to a scale radio then you have a little more work to do. You need to split the end now into two wires. Next using some wire that was a little under 1/16 in diameter cut a two-inch section. Bend in half and attach the bend to the wire to the headset cord. I glued the two sections together then used a small section of black shrink tube to cover up the area. If you want to take it up another notch and get fancy you can take a 1/2-section of 1/16 plastic rod and round the point. Paint it silver. Next take a 1/2-section of 1/8 or 3/32 hollow plastic rod, drill it out to 1/16. Paint it black. Slid the flat end of the 1/16 plastic rod 1/8-inch into the hollow rod. Add a drop of thick ca and now stick your headset cable into the other end. Now you have a 1/4 scale 1/4 inch plug! You will need two plugs for each headset.
The mic boom is made from 1/16 diameter electric wire (I used a wire with black insulation on it.). Bend ¼ inch of the wire down at a 90-degree bend. Now insert the bend into a 3/16 then washer. Apply some epoxy to form a nice fillet between the washer and the wire. With the headset on the pilot insert the boom into the headset and bend to fit the pilot and trim to length. I use a ¼ inch length of hollow 3/32 plastic rod as the mic. Paint it flat black and glue to the end of the boom. Now glue boom to the headset.
As I said it will take a little work but you will have the best looking headset at the field!!!! For a fee I will press form the parts for you.