View single post by Ray Dunakin
 Posted: Sat Nov 24th, 2012 02:08 am
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Ray Dunakin

 

Joined: Wed Jul 25th, 2012
Location: San Diego
Posts: 1242
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With my computer in the shop for over a week, I had lots of time to work on my railbus project. First up was making the headlights. I built the headlight body out of styrene tubes. There are designed to open from the rear, so that the LED is accessible in case it ever needs to be replaced. Here are the headlight components:



The headlight lenses were made from elliptical acrylic domes from Plastruct. I don't know what size they are, they're just something I had on hand. They were too wide so I traced the correct size onto them, then reshaped them using a Dremel with a cutoff wheel. A sandpaper stick was used to fine-tune the shape. They were also too thick so I used coarse sandpaper to sand them thinner. This had the added benefit of creating vertical lines that simulate the look of old-fashioned headlight glass:




I added a styrene base to each headlight and then glued them to the end beam of the chassis. Then I painted the chassis, first with a coat of red primer, followed by gloss black:




The lenses were inserted into the front of the headlight casings and secured with MEK:




The LEDs were mounted in the rear section of the headlight, which slides into the headlight casing. I used 3mm Warm White LEDs. To keep the LED centered and pointed forward, I had to support it with two short, telescoped sections of styrene tube. These are removable:




Here's a shot of the finished headlights with the LED assemblies installed. I got the LEDs from modeltrainsoftware.com, and they come wired up to a tiny package of circuitry that limits the voltage and provides correct polarity no matter which way the leads are connected to the power source. I had to route the wires around the motor mount, and glued the LED circuits to the top of the motor mount:




On the underside you can see how the LED wires were routed through the chassis. I tacked them in place with a few small dabs of hot glue. If it ever becomes necessary to remove or replace the wires, it should be pretty easy to pull them loose. The undercarriage was weathered using a mottled blend of brown and black acrylic craft paints. I later applied the same colors to the wires, to camouflage them:




The tail lights were made from 1.8mm red LEDs. These have a rectangular base with a small, protruding "bulb". Although they glow red, the unlighted LED is clear. They also glow very brightly, so to tone down the brightness and give them a red lens, I painted the ends with opaque, glossy red acrylic. Then a short section of 1/8" styrene tube was glued on, and the rim sanded to round it. The exterior was given several coats of black paint, with a bit of metallic "steel" paint added to the rim. Then the LEDs were carefully hot-glued onto the undercarriage. The wires were routed into the rear of the chassis and weathered:








Here's a shot of the completed electronics and battery installed on the chassis. I painted the wires grimy black to make them less visible. The battery is held in place by a small strip of double-sided tape:




The LEDs were connected to a spare Losi power plug (A), which was soldered to the motor output terminals (red arrows). The LEDs come on only when there is power to the motor. It would have been nice to have the LEDs on when the vehicle is stopped, but I couldn't figure out how to do that, and it probably would have drained the battery too quickly anyway. The battery's power plug is at (B):




Another small addition to the vehicle was steps at the sides and rear door. I fashioned mounting brackets out of brass bar stock, held in place with thick CA glue and Ozark Miniatures NBW castings. I had to heat the brass in order to drill holes for the NBW castings. Afterwards I tried to reharden them by heating them, then dunking in cold water, but that didn't seem to help much. So I have to be careful handling the model, as the step brackets bend somewhat easily.

I made the "wooden" steps out of styrene. These were textured and painted using the same methods I've used on my buildings. After scribing simulated wood grain into the boards, they were given a light coat of white primer, then colored with several thin washes of browns and grays. When dry, a coat of Krylon UV resistant clear matte was added for protection:




I added a peeling paint effect by first wetting the boards with Testor's enamel thinner. Then gloss black acrylic was light brushed on, building it up in areas where there would be less wear:




Here's a shot of the finished rear door step. You can also see the tail lights in this shot:




Painting the car body: I started with a light coat of white primer inside and out. Next I masked off most of the cab interior, then sprayed the exterior with red primer. I tried to limit the amount of red primer that got into the rear passenger area -- a little overspray there was ok but I didn't want a full coat of it.




I wanted the exterior finish to look slightly old and weathered, with just a bit of gloss left. In the past I'd had good results on small items, by brushing on an acrylic color coat topped with a couple coats of thinned artist's gloss medium. So I tried that on the car body. The results are ok but not as good as I'd hoped. If I could do it over, I would just use gloss spray paint for the color coat, then dull the shine a bit during weathering.

The custom decals were provided by Stan Cedarleaf, with his usual excellent service. The roof was painted with silver acrylic, then weathering slightly with very thin washes of brown and gray. Additional weathering was applied later:




The interior of the car was painted in two shades of brown and a coat of thinned gloss medium. The rear passenger seats were painted separately and were not installed until after the car body was painted. As you can see, the wiring is only barely visible through the windows, so no extra steps were taken to hide the wiring:






More to come in the next post...



____________________
Visit http://www.raydunakin.com to see photos of the rugged and rocky In-ko-pah Railroad!
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