The project started innocently enough, upgrading several Stewart F-units to I-M bodies. The Kato mechanisms are excellent but the Stewart shell cannot compare with current highly detailed offerings. I changed the original shells out to those offered by Inter-Mountain and with some weathering, you almost do not notice the I-M’s slightly incorrect nose profile.
The bodies came with the usual clear styrene “lens” which secures in the light opening in the nose but I still need a way to mount the LEDs. The Athearn Genesis F design has the separate lens and prototypical light fixture which hold the incandescent bulbs for the headlights and Gyra lights. And I have modified them to accept SMD LEDs but they do not work on the I-M. Even if they did, try finding just those pieces.
MV Products Version
This company is located in Orange, CA and has been making realistic headlight and marker lenses for decades. They have a very subtle curvature on the front side and the rear is covered with a very convincing bright coating. They are available a variety of colors and sizes and are distributed by Walthers. They look very realistic and their conversion to a working light is quite simple.
Conversion
Not being able to accurately measure the inner diameter of the I-M body openings, I purchased a broad selection of lenses with sizes I believed would be close. Some fit flush on the outside but I wanted a size which recesses into the opening just like the prototype.
One approach would be to remove some of the silver coating and glue an LED directly to the lens with Faller Super Expert or even one of the UV activated products such as Bondic. I think this would work with a 0402 or 0603 SMD LED and maybe some of the top hat style lights if you have the room inside the shell. I wanted more of a bulb look when the light was off. The LED of choice for this project is a 1.8mm in warm white.
Drilling the clearance hole
As I did not have any double sided tape, I used wide, cheap, masking tape as my clamp by folding the ends of a 2-inch long strip 180 degrees to adhere it to your work surface. Double sided carpet tape works, too. Press the MVP lens onto the exposed sticky side of the tape.
Using a metal T pin, (the type supplied Woodland Scenic for securing their Styrofoam road bed), make an impression in the center of the lens. A lighted magnifier makes this step easier. Drill a small pilot hole in the lens with a pin vise and a 70-ish drill bit. Then I used a .0625 drill turned by hand for enlarging the hole. Check the LED fit for depth and appearance.
Once satisfied with the fit, trim the legs of the LED to fit your space and secure the LED into the hole of the lens with either CA or Faller Super Expert and let it dry.
When the glue was cured, I added Bondic resin to strengthen to joint and cured with UV light.
Prepare light leads and solder to the LED.
Installing into shell
Even though the LED is adequately adhered to the lens, use care in installing in the light’s opening in the shell. Insert the leads from the exterior and gently guide the lens and light assembly into position for gluing. I used siliconized acrylic caulk as it can be removed with the tip of #11 blade if needed.
The lens now more closely resembles a real light even when off.
