"Milepost 15": How I Kitbashed the Second Shark

Having gotten the first BP20 "passenger shark" to a semi finished state I decided to build the second one. I modified the first model by following the advice of the guys at Railwire. I replaced the DL109 mechanism with an older chassis that I was using under my FM Eriebuilts...

PA Mechanism

The mech was originally used on a Alco PA and as such is much too short for a BP20. I was told, however, that I could "flip" the trucks end to end. Since the gear tower is off center this makes a drastic change to the wheel base. Makes it exactly the right length to throw under an eighty foot passenger shark...

BP20 Shell on the Modified Alco PA Mechanism

Since the Pennsylvania ran these beasties in sets I need two A units. I have another of these older PA mechanisms and two shark RF16 shells. This is how I kitbashed my 2nd version of the BP20...

A and B Unit Shells

The first obvious step is to find two RF-16 shells. ER and V-Line are the most common. I have a mixture of three although I'm not sure who made the third one. If you can choose use two shells from the same maker. The two I used for this project have slightly different widths and require some filling and filing.

Since the detail on the RF16 differs greatly from the BP20 the first thing I do is remove all the detail. I leave the cab alone for the most part but remove all the side detail of the main body with a #17 chisel blade. I go slowly in light strokes keeping the flat side of the blade as close to the shell as possible. On some shells you must be extremely careful as the plastic is soft and easily gouged. Leave the rear door intact but remove the handrails.

Once the sides are bare I start cutting the shell into sections. The first major cut is directly ahead of the roof intakes, the large triangular humps on the rear roof. I do this on both the A and B unit.

Removing the Rear Section at the Roof Intakes

I had to use a Zona saw for this, but my favorite tool is a kind of microsaw blade that fits the thin #1 handle. It's a small trapezoid shaped blade that I think is out of production. I have one or two and they cut in places the large saws can't. I don't use a miter box, although I have one. Instead I prefer to use a small adjustable square as a saw guide. It's a technique I've used for wood working for years, albeit with a much bigger square. I even cut 2" x 4" this way...

Adjustable Square Saw Guide

The second major cut is on the A unit. I cut the shell just to the rear of the cab. Not right at the door line but a fraction of an inch behind it...

Removing the Cab

After I get the major pieces cut I check the overall length with a scale ruler. I make mine roughly 80 scale feet long. It'll end up a tad longer, but I'm getting ahead of myself...

Checking the Length

With most of the pieces present and accounted for I perform another major cut. The rectangles on the roof are hatches. While the hatches on the front section are pretty much in the correct position, the ones on the rear are too far forward. To reverse them I simply cut the shell just behind the riveted roof panel and flip it end for end. The hatches are then closer to the correct location. Unfortunatly I forgot to take a photo of this step, but you can see the result in the next few images.

The next cut is probably the most important. A major characteristic of the BP20 is the nose. It's quite a bit longer than the RF-16. To make it longer I make two cuts. The first is a saw cut that extends down to the line of the frame. The second is a knife cut that separates the frame from the rest of the cab...

Cutting the Nose

At this point I start gluing the body parts together. While I've tried to use plastic cement to "weld" the parts together I find that superglue works better. I always use the gap filling gel. It takes a little longer to work, but that gives me time to adjust the parts. Once the glue on the cab and other parts has set I go to work on lengthening the nose. I mock up the nose leaving a 4mm gap...

Fitting the Nose

I use two pieces of 2mm styrene laminated together to fill the gap.The part can run straight across. The PA mechanism isn't long enough to reach this far into the nose so there is no interference...

Filling the Gap

The styrene gets sawed into a rough oversized pentagon approximating the outline of the nose. I trace the shape of the nose on the styrene in prepration for the next series of cuts...

Nose Outline

Using the saw again I make the first rough cut. It's a bit oversized so I can fiddle with the shape...

Add caption

I check the fit on the nose again and make a close cut. This time I angle the saw blade so I get a slight miter. I want the rear of the part a hair larger than the front. It is still slightly oversized to allow a final sanding to the proper contour...

Nose Extension Glued in Place

Using files and sanding sticks I try to get the styrene to match the nose contours. Takes a while as I go slowly so I don't gouge the part...

Sanding to Shape

Even if the shape looks close I still use a little filler. I use Testors Contour Putty for this. I tried Squadron Green, but don't like the texture or "appliability" (is that a real word?). The Testors is finer, stays soft longer and can be worked a bit more. I use finer and finer grits of sanding sticks to finish up the shape...

Nose After Contour

Same process is used on the rest of the shell. I add a long rectangle of styrene to the top of the model to simulate the radiator shutters...

80 Feet of Baldwin

The shell gets a preliminary coat of DGLE to highlight the faults in the finish. Some more sanding and filling. The final step in the basic body shape are the body panels. I use 0.010" thick styrene strips to simulate the the panel seams. On the first shell I use 0.010" x 0.040" wide strips but found these looked oversize. This time around I'm using 0.010" x 0.020" styrene. I pin the one end down with plastic glue...

Horizontal Panel Seam

I stretch the strip out and after lining it up I pin the other end down with glue. I then run the glue along the strip, letting capillary action draw in the glue and sealing it to the body. This gets repeated three times on each side for the horizontal seams. I make them overlong and them trim them to size. The vertical spacing is eyeballed. The vertical seams are done in a similar fashion. I place them every ten feet gluing the upper end down and letting it dry. I place them all on one side. When the glue dries on the one end I pull the strip perpendicular and glue the lower end. I let the glue set up and then run the glue along the strip. Last of all I trim them to fit...

Vertical Panel Seams

On goes another coat of paint to bring out the flaws. I fill in any large gaps in the body with 0.020 and small holes and pits with contour putty. More sanding and some scraping and paint and so on and so forth. If some things still don't look right I do them over.