Wednesday, February 24, 2016

Building the Speedwitch Southern gondola

The gon as viewed from the underside with strip added and underbody glued into the car body
The Southern gondola kits were my first efforts when I launched the resin portion of Speedwitch. To say that I tried to have my cake and eat it, too, is an understatement. I hated gondola models where there was a sacrifice in that either the interior side walls weren’t tall enough relative to the prototype or there wasn’t anywhere to conceal some weight. I was determined to make a car where the interior was “the way it should be” and you could still stash some weight. As with most open top scale models, something had to give. In this case, the “give” was the depth of the underframe. I purposely made the bolsters, crossbearers, crossties, and center sills shallower than the prototype in order to achieve a prototypical car interior and have somewhere to put some weight. That also meant that the coupler pockets were forced to sit right on the underside of the gondola floor, in a “cut-out” in the underbody. This also makes it a challenge to secure the coupler pockets. In retrospect, I probably bit off too much. I am certain there are many out there who are still trying to figure out how to build one of these successfully. What follows is what I hope will be a step-by-step guide to augment the kit’s instructions and explain one person’s path to building the car into a beautiful and operable model.
The interior with the floor attached
The initial step is to clean up the main body casting, comprised of sides and ends. My course of action was to rub it back and forth on a sheet of 220-grit sandpaper on a flat surface. I held the casting in between thumb and forefinger and rubbed the casting parallel to the line of the surface I was holding, switching the places I was holding frequently to avoid removing too much material in any one location. By “parallel to the surface I was holding,” that means that if I was holding the car side, I moved the length of the car side back and forth along the sandpaper. Conversely, if holding the end, I moved the length of the end back and forth across the surface of the sandpaper. In a fairly short amount of time, the casting “flash” inside the top of the car body became thin enough to flick away in most places. In those areas where there was still a little material holding the flash in place, I held the casting in that specific area and moved it across the sandpaper as described previously. Once the excess material had been removed, I cleaned up the top edges of the car with a sanding stick (read about sanding sticks by clicking.)
An additional view with the underbody added and the strip styrene visible at the edge
The first snafu involves the floor of the gondola. This is the part with detail on its surface that fits inside the car body and faces up when the car is on the rails. It is slightly too long (this is okay) and slightly too narrow (not okay.) It must be made marginally wider. To do this, I added 0.020” x 0.020” styrene strip to the edges (the long edges) of the casting. This was actually really easy to do. I simply laid the casting on a flat surface with the styrene strip butted against it and held in place by my finger and added a little ACC along the length using a straight pin as an applicator, moving my finger as I went, to expose the areas I hadn’t attached. It took less than five minutes. Work in small drops rather than big gobs and there will be no ACC mess or parts stuck to your work surface. It doesn’t hurt to keep checking as you go, though, to make sure your part isn’t attaching itself to your work surface. With the styrene strip added, the casting is ever so slightly too wide. A few (and I mean a few) passes of the casting over sandpaper on a flat surface should narrow things enough to fit inside the car body. To do this, hold the casting on edge and run it over the sandpaper. I always run it the same number of passes in one direction, the other direction and then flip and do the same for the other side. It’s not entirely scientific, but it does remove roughly the same amount from both sides. Do the same to shorten the ends of the casting and it should fit snugly, but not tightly, inside the car body. It fits inside the lip that is in the car body, meaning the edges of the casting you just narrowed will not be visible once the floor is glued inside the car body, if viewed looking “into” the car body, as you would if it were on the rails.
From the top, the undeframe, car body and underside of floor, and the lead weight, all with the Goo and MEK mixture added to the surfaces
Gluing the floor inside the car body is a relatively easy process. Put the car body casting on a flat surface upside down, with the top edges of the car body in contact with the flat surface. Place the floor inside the car body. You should be looking at the undetailed (“underside”) surface of the floor. If you are looking at the rivets, stop and reorient the parts. To glue the floor into the car body, there are two key things to consider: 1) work in small increments, rather than trying to glue it all at once and 2) a light pressure is all that is needed; a death grip will surely create distortions in your body casting meaning either the sides will be grossly bowed or you will induce “torque” along the length of the car body, resulting in a pronounced twist to the body. Gently push the floor into the car body so that the floor rests inside and snugly against the lip in the car body. I found it easiest to start at the center of the car and then work towards one end followed by the other. With light pressure, gently press the car body together with thumb and middle finger while applying slight pressure with the index finger to keep the floor pushed into the car body. The thumb and middle finger should be applying pressure near the edge of the car body that is closest to you (and where the floor casting is contacting the car body), not the edge that is touching the flat surface on which you are working. Applying pressure where the car body is resting on the flat surface will cause the car sides to bow, angle or cant inwards. Gentle pressure using this three-point approach with thumb and two fingers applies all the force necessary to keep things in place while you add the ACC. Add some ACC where you are applying the pressure to the joints on both sides of the car body (at the places where both thumb and middle finger are holding things together). Hold until the ACC has set up the joint. Repeat at several points until the floor is secure from the middle to one end and then repeat from the center to the other car end. As you work, make sure that the floor is nested all the way into the lip in the car body. This is your one chance to get this correct. Go slowly, checking your progress frequently. Once you have tacked everything in place, go back and add ACC along the entire floor/car body joint. If all is well, you should have the “bones” of a gondola in your hands!
The car body with weight attached and awaiting addition of the underbody casting
The next series of tasks involve addition of weight between the floor and underbody followed by gluing the underbody into the car body. For the weight, I have a large roll of 0.020” thick sheet lead that is perfect for this car (I believe it is some type of flashing for use in the roofing industry). I cut a piece of lead to fit exactly into the cavity under the floor, minus the notched areas where the coupler boxes would be located. I “painted” the underside of the car floor and the top of the weight with a mixture of Walthers Goo and methyl ethyl ketone (MEK). The MEK makes the Goo less viscous and able to be brushed on to surfaces. Once the Goo had thoroughly dried, I dropped the weight into the cavity and carefully pressed the two surfaces together, between thumb (on the lead surface) and forefinger (inside the car body). Don’t put the car body upside down on your work surface and just push on the underbody. You could damage or deform the car body. Use the thumb-forefinger technique described above as it places pressure only on the floor and underbody, not the car body. I brushed the Goo on to the still exposed lead surface and the “top” of the underbody. Once again, I let the Goo dry before adding the underbody and again pressing the surfaces between thumb and forefinger. This completed the basic assembly of the car body.

The modified coupler boxes as described in the text
The coupler and "draft gear" as attached to the model
The next task was the addition of the couplers. I used Kadee no. 153 scale couplers in the Kadee-supplied coupler boxes (“draft gear”) modified as shown. The no. 153 coupler is the same as the standard no. 158, but with a shorter shank length that was better for this car. The basic modifications included shortening the main half of the coupler box (the piece with the circular post and the “sides” of the coupler box) to butt against the inside of the end sill, and narrowing the front lip of the other half of the coupler box to fit between the draft gear opening of the car body’s end sill. Lastly, I added bits of HO scale 1x4 strip styrene to complete the “sides” of the coupler box that extend past the draft gear. The next challenge to overcome involved actually securing the coupler boxes to the car body. After some deep thought, I came up with the following plan: I would run a piece of 3/32” styrene tube through the post of the coupler box and, after drilling a hole in the floor, straight through the floor of the car. Yes, it meant a piece of styrene rod protruding from the floor of the car and subsequent sanding and cleaning up of the car floor after my “surgery”. The converse, though, is that I had a secure means to attach the couplers, beyond just gluing them (and we all know how that ends up: a coupler and lid sitting somewhere on the layout with half a train sitting uncoupled behind the coupler!) After all, the styrene rod isn’t moving and it has a hole that can accept a screw to secure the coupler boxes. That’s what I did. After everything was in place, I added a small bit of styrene rod into the center of the styrene tube visible on the top of the car floor (the hole in the tube on the underside of the car needed to remain clear to accept a 0-80 screw to secure the coupler box.) I am in the process of filling and sanding the floor of the car to clean up my mess. That’s where I will leave things for the moment. Because the tight spaces on the floor between rows of rivets dictate careful sanding, I created my own sanding tool that is a piece of styrene tube, cut at an angle at one end, with a piece of 4x10 HO scale styrene strip glued to the angled end, with a piece of sandpaper glued to the face of the strip (using the Goo/MEK solution). I had made some of these years ago for a similar situation, and I cannot remember if it is something that I created or saw somewhere else and emulated. Either way, it’s the right tool for the situation. See the photo.
Note the visible styrene rod at each end. As viewed here, all that remains is some fine sanding
The "tool" that I created for sanding the top of the floor. It consists of styrene tube, a bit of strip styrene, and some sandpaper glued to the face of the strip
All the hard work is done and I have proven that my over-engineered gondola can be built, although it takes a little planning and ingenuity. To be continued as the car is detailed and painted…
A view of the underbody

1 comment:

  1. Lol. This post is fantastic. I had gotten tired of looking at my almost completed model (just needed paint and lettering) because the underframe sat too low. The real problem was not only didn't it look correct, but the couplers sat too high.

    So I actually disassembled it the other day, which was a bit of a challenge. I had tried a few new tricks, like adding a chain that is attached to the bottom of the brake staff to the brake rod, which is also attached at the other end to the lever and the cylinder by another chain. So I can't actually completely disconnect the under frame from the body now, just hinge it with the chain.

    Of course, my problem is the thickness of the lead that I have, so I'll have to hunt down some .020" lead. I had been experimenting with not using the lead all the way to the sides of the floor, so the floor could bow slightly to accommodate the extra thickness in the middle. Now that I have a thickness to look for I'll start there.

    Thanks for the timely post!


Comments always welcome!