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Thursday, September 23, 2021

SPMW 7021A (Part 4) Wrecker - Rail & Tie Car

During the last three parts of SPMW 7021A (Part 1), (Part 2), (Part 3), construction and kitbashing, the rack and bulkheads have been fabricated.  It's time to finish one of the my most concerning details and get the new rack ready for paint.

Time to finishing painting the rack in this post!

Fabricating the "Hanging" Grab Irons


SPMW 7021A post-1958 photo - Eddie Sims collection

Looking at the prototype photos, there is a huge gap between the grabs on the side sills and the grabs at the frame level of the rack.  On the prototype car, there was an additional set of grabs suspended from the rack frame, which will allow rails to be pulled from the main deck of the car, yet will still be the correct height to allow easy access to the running boards on the top of the rack.

Grabs and Styrene Hangers

I decided to use 0.015"x0.040" styrene strip for the vertical hanging structural pieces.  The grabs are formed with OMM jig using 0.012" PB wire, to the "long" jig setting.

Marked hole, calipers and carbide scribe to mark hole center

I drilled the hole in the styrene strip 0.125" from the lower edge of the rack frame (same as the top of the hanging styrene strip).  The prototype steel piece has the grab at the very bottom, however I want to have a small amount of plastic around the grab iron, so I left it about 0.015" longer than where I drill the hole.

Completed grab irons and hanger strips

I inserted the wire grab into the hole in the styrene, then applied a drop of ACC glue to the back of the styrene.  With a small piece of scrap wire, I transferred a bit of ACC to the front side to finish securing the grab at a square angle to the styrene.  Note that I made two "Left" and two "Right" configurations of this assembly.

Completed A-end right side grab iron and hanger

The holes in the bulkheads were predrilled during Part 3, in anticipation of this coming step.  I apply a small amount of ACC to the remaining wire end of the grab iron.  With my favorite Leatherman pliers I grab the grab and press it into the hole in the bulkhead.

B-end right side grab iron and hanger

B-end left side grab and hanger, top grab is a little off level - oh well.

A-end left side grab and hanger

Next, the styrene strip is rotated up against the bottom surface of the rack frame.  Tamiya liquid glue is used to weld the styrene pieces together.  As it starts to weld the joint, I make sure to press it flush with the outside edge of the rack frame.  Often I used handles of metal tools, such as my tweezers, which can be used to align the plastic parts, but will not be effected by the liquid plastic glue.

A-End Additional Supports


New horizontal supports installed on each side of tie rack bulkhead.

I decided to put in two more 0.020"x0.040" styrene pieces between the upper rack bulkheads and the flat steel gussets to support the A-ends of the running boards.  These two pieces were a bit tricky to install, but with a bit of pre-softening with Tamiya liquid glue was easier.

Stanchion Top Cables


New 0.009" top cable threaded through stanchions

The top cables (0.009" PB wire) are now fitted through the tops of the H-column stanchions on the rack.  One end is bent over and secured with drop of ACC.  The other end is also secured with a small drop of ACC on the wire, then pulled into place and allowed to dry.

Masking & Painting


As with all things SPMW before 1958 and that wasn't a crane or a snow plow, SP Freight Car Red (FCR) is the color of the day.  The main body of the car would have already been painted FCR from the revenue service days.  The conversion date in 1939, I'm not 100% sure if the new tie rack was welded directly to the frame as it seems, but in any case, it was then painted overall FCR according to the 1950s photos I have of the adjacent cars from Bob's Photos.

I don't want to risk the deck weathering putting any masking tape down directly on it at this point in the painting and finishing stage of construction.  So, I need to make a non-sticky mask to keep my nicely weathered and distressed deck from getting any over-spray.

The main desk mask is cut from some standard paper scrap.

My mask is made from a scrap of standard 8.5x11" paper.  Two creases are formed for the width of the deck.  The paper is cut to the internal distance between the bulkheads.

Slipping the mask into place.

The mask is carefully slipped in between the main deck and the hanging grabirons.  A couple pieces of 3M Scotch tape are used to secure the paper around the body of the flatcar.  I needed to tighten up the paper, so I added a small amount of extra tape to cinch it a bit tighter.

Partly painted rack.

My finger grip would help bias the mask and pull it tight at the lower edge of the interior bulkheads when I was going to use the airbrush.

Painted rack completed and mask removed.

It looks pretty good.  It took two loads of SP Freight Car Red StarBrand paint in my airbrush to cover all the nooks and crannies of this complicated structure.  Best to just do light coats and keep going around the various areas, hitting all the angles you can see.

In Closing


Now the rack just awaits the wooden parts.

Well, this pretty well finishes the construction of the SPMW 7021A.  In the next post, I'll be building the running boards for the rack.  These will be made using pre-stained wood for those parts.

I'm also planning to build a load of rail and a frog for the main deck and ties for the rack of the car.  I hope you'll come back again to see the next post in this series.
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