Monday, June 27, 2016

Modeling The New Haven DEY-2, Part 2


This is the first model that I tried to record the construction progress in a photo log. I am a modeler first, not a photographer! I get so interested in the modeling itself that I often forgot and still do forget to take photos of some of the steps in the model building process.

When this model was built I had just acquired my first digital camera. Many of the photos reflect my inexperience with this simple point and shoot camera, the photos do get somewhat better as the model neared completion. Although some of the photos are quite poor I hope they are sufficient enough to get the point across.

As stated in the last post, I had no dimensional blue print for the superstructure of the New Haven DEY-2 switcher. All dimensions were taken from a traced GE drawing that was resized to HO scale. As the dimensions for the model were taken from that drawing, I made no record of the dimensional data of the model as it was being built therefore none are offered in these posts. I do hope though that some of the modeling techniques may be useful in building a model needed for your railroad.

The Long Hood.

The last post showed how the detail was removed from the long and short hoods of an Atlas RS-1 body shell and that these hoods were then shortened to reflect the length of the hoods on the DEY-2 switcher.

This post will concentrate on adding a thin styrene layer over the long hood of the Atlas body shell to represent the basic details of the outside skin of a DEY-2.

Re-Siding the Long Hood

Note that before the hood ends of the shell were shortened the inside width of the Atlas RS-1 shell was measured. Using that measurement, a sturdy piece of styrene was cut to size and glued in between the two sides of the shell before the original ends were removed. This reinforcement piece will hold the inside dimension to the original spec and the sides square to each other after the original ends are removed. The below photo shows this piece in place.

Click to enlarge photos

There are three things to note in this second photo.

1. As mentioned in part one, the Atlas hood is a little short in height, a strip of styrene has been added to bottom of each hood side to raise the hood to the correct overall height.

2. A rectangular notch was been cut into both sides of the front edge of the hood, these notches will house the sand filler hatches. These notches were cut into the sides before the new end piece was glued into place.

3. A piece for a new structural end is glued to the end of the shell. The width of this rectangular piece is cut to the exact outside width of the Atlas shell, the height of this piece is taller than needed and will be trimmed off next.

This next series of photos is just to show that it is easer to accurately cut the curvature into the new end after it is glued in place opposed to trying to do it before hand.

Trim off excess material

 Finish up wit a flat file
The finished piece forms a new structural member for the end of the body shell.

The shell is now ready to be re-sided with a layer of .010" styrene, this layer will represent the outside skin of the long hood or the layer that the eye will see on the finished model.

The end of the long hood has two access doors, The first three pieces of the outside layer will outline the opening in the end of the hood for these doors. The larger of the pieces is again cut to the exact width of the Atlas hood.

In this photo the three pieces have been glued to the end of the shell defining the opening for the two end doors. The top edge of the large piece was trimmed to fit the curvature of the hood using the same method as the structural piece underneath.

Below is the beginning of the basic overlay of the hood sides and top. This .010" styrene overlay is very pliable and easily bent, will hold its bends much like folding a thick piece of paper.  It is very important to cut this piece perfectly square to insure a good fit in the end product.

The following is a quick way to get the correct dimension for the overlay piece from side to side. Take a long strip of .010" styrene and clamp it even with the lower edge on one side, then tightly rap it over the top of the hood down to the lower edge of the other side, clamp it, then cut it off even with that edge. Measuring the length of that strip will reveal the total side to side dimension need the overlay piece.

The length of this overlay piece from the cab to front of the hood is to be cut the same length as the Atlas shell without adding for the thickness of the new end pieces, this will provide an allowance for two panel gaps in a later step.

Below is the bent overlay piece. After removing the clamps and setting the piece aside the bends will spring back to a lesser angle than needed. Later when needed the bends can then further bent over to the permanent angle required, again much like folding a piece of heavy paper.

The top of the prototypes sheet metal hood was fabricated in three sections, a long center piece and two shorter pieces, one at the cab end and the other at the hood end. These separate sections can be seen in part one on the finished model and also the GE drawing.

The bent overlay below is cut into three sections using the GE drawing as a guide for the dimensions. Note that the separation lines used to snap the styrene into three sections were scribed into the back of the overlay sheet before bending.

Using the GE drawing and prototype photos as a guide to determine where all the panel separation lines/gaps are, the first section of the now three piece basic overlay is cut its final size.

This first overlay panel is now glued to the supporting under shell making sure to also cover both layers of the new front panel.

A styrene liquid solvent cement (Testors) was used for this. This glue will not mar the outside surface of the thin .010" overlay pieces if used sparingly. I like to apply it to the back of the piece being attached using a scrap piece of styrene as a squeegee to spread the cement evenly then letting it flash off for a few seconds before positioning, there is a short period of working time for making positioning adjustments before the piece becomes permanent.

The notch for the sand filler hatch below is reopened easily with a sharp #11 blade.

This is one of those photographer holidays where no photo was taken of the components of the sand filler hatch before assembly . It is basically made from four strips of styrene glued to form a box, then a fifth piece bent and inserted into the box. A photo of the components will be shown in the building of the short hood.

The sand filler hatch is inserted into the shell, positioned, then glued from the back side.

With the sand filler hatch in place the three pieces for the single door under this section are cut to size. The door is the center piece, the other two pieces represent fixed in place panels.

These pieces are glued in place leaving a .010" gap around the door including the bottom to represent a clearance with the walkway for the door to swing open.

This next photo shows that the remaining two sections of the basic overlay have been affixed to the shell.

Aligning the smaller section that is closest to the cab, with the back edge of the shell where it meets the cab, this smaller section was then glued on first. This section remains full sized with no modification.

The large center section needs to be cut to size as seen below. It is important that the bends fit the shell tightly before the sides of this section are cut to the final size. This can be achieved by over bending until the styrene retains enough memory for the bends to tightly fit the shell. This is done before the sides are cut off, for once the sides are gone you will loose the leverage that they provide for making the bends, making further consistent bending near impossible.

To glue the center section in place, ACC is used for a secure and quick curing bond at the bends. To prepare the center section for gluing  to the shell, properly position the section in a dry test fit, a sharp pencil line is drawn on the shell along the bottom edge of both bends and the section is removed from the shell.

Using one of the pencil lines as a guide, ACC is applied to the shell from the line up and over the radius of only one of the bends, quickly, again using the line as the guide the center section is carefully repositioned on the shell until the ACC is fully cured at this one bend. Next lift the center section just enough to add a small amount of ACC under the top of the hood, then add more over the hood radius down to the pencil line of the opposite side squeegee out then quickly lower the center section onto the ACC to secure the panel in place.

To make short of the long, accurately position, then glue one side till cured then glue the rest.

When positioning the center panel there should be an approximate .010" panel gap between the center section and the sections on both ends.   

There are two fixed panels, one on each side of the opening that frames where the row of side access doors will be. For ease stock sized styrene strips that closely matched to the drawing were used for this. They were glued onto the sides with a .010" gap that matches and continues the panel gap across the top of the hood, then cut off even with the bottom edge.

This next photo shows all the door and fixed panels that go into the framed opening outlined in the last step. There are six doors in total, four wide and two narrow. There are five fixed panels, one wide, one narrow and three very narrow, the four narrow ones are again a stock size styrene strip for ease.

When sizing the width of the doors and large remaining fixed panel, the sum of the width of the four narrow stock sized styrene strips plus twelve panel gaps of .010" each must be subtracted from the overall width of the framed opening.

Using a .010" piece of styrene as a feeler gauge in the panel gaps is helpful aligning the panels while gluing.

Here all the panels have been glued to the supporting under shell.

I add this last photo just as a reminder that it is very important that all the pieces of the overlay must be cut squarely and affixed squarely for it to all come out correctly in the finished product. This is not hard to do, just very time consuming and tedious!!

Next part will have a look at the cab.

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