With all the non-modeling related postings on TRW (I am partially to blame here too), I decided to post what I've been working on since last weekend. In my collaboration with Roland Kelley on his carnival extension N-Trak module, I needed to find some bumper cars. Since nobody makes these in N scale, I had to scratch-build them. Here is a quick write-up of how I did it.
I first gathered some photos of bumper cars. I then got some rough dimensions. These are the prototype on which I loosely based my model.
Since I needed a bunch of them, I had to make a master pattern and cast them out of urethane resin.
I started with a piece of acrylic (Plexiglas) which I cut to the scale length and width of the car. The scribed mark denotes how high the car needs to be.
Next ,using a saw, files, and dental grinding bits in a Dremel tool, I removed all the material which was not the bumper car's body.
I then scribed the front grille and a trim line around the body. Then I polished the body using an 4-grit fingernail polishing stick.
Here is the obligatory coin photo for size reference.
The steps which I didn't photograph (I should have) were milling machine operations: Using a 0.025" mill bit I made a hole for the electric pickup pole in the rear and holes for 0.025" styrene rod I would use for the headlight pods. Then I glued in the styrene rod and trimmed it to represent the headlight pods. I then separated the car body from the rest of the acrylic piece.
Then, using a piece of 0.032" acrylic sheet, I made the "rubber bumper" base for the car.
Base glued to the car body (using a methylene chloride based liquid cement).
I then glued the master pattern to a flat acrylic base.
Using masking tape, I created a dam to hold the RTV rubber and ...
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...poured the liquid rubber into the cavity. Once the rubber hardens, I remove the tape and pull the rubber mold off the master.
Here is the first molding popped out of the mold.
I photoetched the steering wheels. Then I soldered them to a steering column made from a 0.010" brass rod.
Steering wheels ready to be painted black.
A finished bumper car. The body and the bumper areas were airbrushed with Scalecoat II paint and the seat and grille/headlights were brush painted (under a microscope).
Here is a couple on a Nickel ....
And a whole gaggle of finished models.
Before you ask, yes, I had to cut off the feet of the figures before I plopped them in the cars.
I'll try a 2-tone paint job on the next batch I'll make. I am totally nuts for making them this detailed, since they will be placed inside a covered arena, viewed from about 2 feet. But I just couldn't help myself...
