Sunday, December 21, 2014

Building a resin box car

On a couple of occasions, readers have asked me if I would go through the steps of building a resin freight car. Resin car kits vary quite a bit in degree of difficulty, from one-piece body moldings of simple cars like flat cars, all the way to genuinely challenging and difficult cars like vinegar cars or insulated tank cars. I will go through the process first with a relatively simple car, a one-piece-body kit from Speedwitch Media.
     Here is the kit box, and it describes the contents, a CB&Q XM-25 or XM-26 box car (the two classes were virtual twins). It is Speedwitch kit K106.1. Atop the kit box you see the one-piece body. This saves the step many modelers find challenging, which is to assemble a body box from separate parts for sides, ends, and roof. On the other hand, much detailing needs to be added to the body, including grab iron rows acting as ladders. That’s relevant because the walls of this one-piece body are thick, meaning more work to drill all those holes for grab irons.

     My first step in any kit is to deal with what I call the “mechanicals,” the mechanical aspects which are good to confront as soon as possible. These are the attachment method for couplers and trucks, and any attachment of car weight. I greatly prefer attaching trucks and couplers with screws, usually the 2-56 size, as that method permits easy removal and re-attachment if needed, and in particular facilitates maintenance on couplers. A kit that is set up to do these attachments any other way (such as friction pins for truck attachment, an appalling method) will have to be changed.
     This Speedwitch kit has a one-piece molded underframe, so it only needs to have holes drilled and tapped for trucks and couplers. I like to use a drill press for these jobs, as it helps ensure making a hole which is perpendicular to the plane of the underbody.

     I use a hand tap, as many modelers do, and here again, it is important to keep the tap entering the hole in a perpendicular orientation (whenever the hole does not penetrate very thick material, as with the coupler box pads on this kit).

     With those tasks done, I glue on some weights (not provided in the kit). As I often do in such cases, I chose to attach a pair of 5/8-inch steel nuts with canopy glue (if you”re not familiar with that glue, you may wish to read this: ). The surface of the resin floor is roughed up a little with sandpaper before gluing.

Here are the two nuts in place. You can see the holes drilled for trucks and couplers, with the nuts well out of the way of those holes.
     This completes the “mechanicals” phase for this kit. Next I start the detailing.
Tony Thompson


  1. This is great. I'm looking forward to the rest of the series.

  2. Again - great stuff!

    For those who have been in the hobby for 10, 20, or more years, perhaps this is a bit basic. But, for some of us who are relatively new to railroad modeling in general and resin kit building in particular, this provides great insight into how someone with lots of experience does it, without having to ruin one or more $50 kits.

    Can't wait for the next installment. Thanks Tony!

    George Corral