SP Jawbone Branch (Part 55) - Installing Spur and Foam Scenery for Owenyo#3

I've been away from the layout for most of a month... so let's get caught up with a series of photo-blog... Pblog... plog?... anyway... This is just a smattering of my pictures I took in order.  There will probably be several posts in this series of photos.  Mostly you'll see lots of clamp pictures - but that's what you get when you're assembling the layout!

Sept 8th Photos Starting at Midnight

Time to make the decision by starting to work on the trestle spur roadbed.

I'm using the 3ft bubble-level as a straight-edge to clamp the spur's inner vertical frame to before gluing.  This will keep the frame straight, so it won't be wavy.

Looking towards the window, more clamps.

The transition to the spur's curve also clamped straight.  The front edge will be bent around to match the layout "cookie cutter" top sheet shape.

Planting more clamps to hold the pieces where I want them.

Notching of the vertical frame member over the cross span frames, which connect the main frame and the main track spline roadbed.

Time for more clamps on the diagonal brace frame.

Everything clamped together for the glue to dry.  I didn't want the spur's frame moving, so the lower clamp is holding the spur's frame at the right distance along the diagonal sub-frame.

Back checking where the front spur frame lands on the wall.

I use water to pre-wet the structure before I put the glue on.  There's an area of "wetted" rear frame still showing, as the applied Gorilla Glue is about to start expanding over the later photos.

Lots of drop-clothes in the form of paper towels to keep the drips from causing trouble.

Small amounts of Gorilla Glue is starting to expand from the first angled joint.

Starting to clamp around the curve.

Again, wetted MDF for the bonding with the Gorilla Glue at the start of the spur's curve.

Main cross brace on the primary direction of the #3 Module frame.

Expanding Gorilla Glue filling in vertical gap, but I was still concerned how strong this joint would be, given that I made square-cut notching in the frame-strip.

Back Frame joint.

The glue filled in around the rear frame joint.  The notches in the frame make it level, to my pre-glue dry fitting.

Filling in frame joint with glue.

I applied a good amount of extra glue around this joint, and used some plastic bag material between the module frame and the wall-bracket, so the module won't get glued to the wall!  I don't mind the glue squeezing out, or expanding, but I don't want to break it off of the bracket later.

Time to Work on the Top and Rear Frame

Time to start putting in the cookie-cutter roadbed top, which required ~1/4" shims underneath.

Overview of the end of the standard gauge spur, which will be under the trestle.  I placed some shim material under the top-surface roadbed to hold it at the right level while the rear frame is glued in place.  At this stage I am dry-fitting everything.

Box-section rear frame being glued in place.

This type of dry fitting is good, as I need to practice how I'm going to clamp it when I have glue on the parts.

Waiting for the glue to dry on the straight portion of the spur roadbed.

I'm cross checking the way everything fits at this point.

How much more can I do while the glue dries?

And, what's it like with the piece of flex track in there?

Still waiting for the glue to dry.

Checking the view down the curve.

16 Adding shim along short-wall support for the spur's curved roadbed.

Let's add a bit of shim to support the edge of the roadbed curve against the rear-frame, along the right wall.

Looking down at the right end of the #3 Module.

Downward view of the wall between the window and doorway.  Marks in place to show where I'll be cutting it of.  This allowed me to move the spur radially around the main track.  The extra material would then be cut off.

Time to Glue

Ok, now to the rear Spur Frame.

Level-bar checking that the spur is on the correct level and the spur is "flat" without any humps and dips.  It will need to be, as the future trestle will want to be on a constant surface.

I wanted to use the level to keep checking the flatness of the roadbed.

And now the forest of clamps comes into play again.

Wow, that's a lots of clamps!

Another view of the clamp forest.

Time to Mock it Up

Now that the spur roadbed is stable, time to see if everything fits.

I make a number of test fittings to check everything, evaluate how the views of the layout look, etc.

Let's check from the doorway, lift-out area.

Backing up a bit to see how the curve comes into the main track.

More views

The "reverse" view checking how everything looks.

Close-up of the joints under the trestle roadbed.

Detail view of the footings of the trestle and how the front frame glue is bonded.

"Doped" Paper Towels?

On old balsa wood airplane kits, the final skin of the model used to be made with tissue and "dope" which was a varnish, which would tighten the tissue as it dries.  I've also used techniques like this to make 'tar paper' on roofs of cars and buildings.  I decided that I wanted to do something like this to contain the glue drips and provide more bonding area around the weird angled joints in this module.

Front main frame and front spur frame.

Close-up of the application of paper-towels to form both a bag around the wet Gorilla Glue, keeping it from dripping, and also to provide effectively a "fiber-glued" structure around the joint, adding strength.

Cross brace near the left end of the spur's roadbed.

Close-up on another example of cut paper-towel filling in square-cut joint, and allowing the glue to fill the void.

After Midnight (Sept 9)

Another Midnight Mockup!

Another overview of the whole module with train posed as a mockup.

Time to Lay in the Foam

This is a dry fitted piece of foam for the rear section.

Now that the basic parts of the spur's roadbed has dried, it's time to start installing the rear foam pieces into the rear portion of the module.  I made sure not to let the left end of this foam get too low into the pin and bolt connection to the #2 Module.

Dry fitting the rear foam panel.

The next section I worked on was the rear piece that would fill in the rear corner of the module.  This section will wedge in well, but also have some glue to secure it.

The edge of the rear foam block will be cut down later.

It's good to finally see the module filling in for the first time.

A nice high view of the foam and positions of the relevant pieces of foam.

Starting to lay in the foam between the main track and the trestle spur pit's roadbed.

Back to a track-level view of the whole spur and trestle area.

The foam is now filled in from the rear piece along the right wall, following the edge of the spur.

A view of the trestle with the various pieces of foam filling in.

I like coming back and taking photos to check against the prototype photos to see how the layout is coming together.

In Closing

Time to see what the local with a 2-8-0 will look like switching this part of the layout.

Let's have another mockup!  Sadly, being a "nightowl", my work on the layout during these late summer days starts at about 9-11pm and stops somewhere around 3-4am.

Next time we'll look at Sept 14th, nearly a week later, as I continued to work on the smaller pieces of foam being put in.

Jason Hill

Related Articles:

SP Jawbone Branch (Part 54) - Roadbed & Rough Scenery for Owenyo#3 (Aug 31-Sept 6)

Jawbone Branch Layout Build Index

OwlMtModels Mini-Kit Conversions for Accurail 40ft Boxcars

Time to upgrade my Accurail SP single-sheathed boxcar fleet

This post is to finally show the new conversion ends from OwlMtModels to make the basic Accurail 40ft Single Sheath USRA clones more like the SP B-50-8,10,11, and -13/14-class cars.  Accurail has offered these kits with either a 1920s "7-8" pressed steel end or a 4-vertical post wood-sheathed end.  Unfortunately, neither is right for SP's ~8000 single sheath boxcars of this rough design.

The stock wood ends of Accurail boxcars are nice, but the details on the ends aren't correct for the SP's boxcars.

Over the years I've built over 20 of the Accurail cars for my fleet during the late 1990s and early 2000s.  While resin models of these cars are available, I don't really want to build a new fleet of resin kits when I have so many Accurail cars already in my fleet.  Now that I'm building the Jawbone Branch layout, these converted Accurail cars will become the backbone of my SP wood-sheathed boxcar fleet.

The answer in the form of OwlMtModels' newly designed 3d printed ends.

The ends are 3d printed and include a large flange on the interior side to bond to the interior of the injection molded roof and sides of the Accurail body.

Multiple versions are in the works at OwlMtModels:

* OMM 4072 B-50-8/10/11 wood ends (with option for either plain end or lumber-door end.)

* OMM 4073 B-50-13/14 rebuilt steel Dreadnought Ends, vertical staff hand brake. (Almost all B-50-14s and many B-50-13s fitted during the 1930s.

* OMM 4074 B-50-13 As-built wood ends (with option for either plain end or lumber-door end.)

* OMM 4075 B-50-13/14 rebuilt steel Dreadnought Ends, with lower platform for power-brake refit.

In this post, I'm only working with pre-production samples of OMM 4073 and OMM 4074, which will be made available for sales at the SPH&TS 2024 Convention in Sparks, NV in mid-October.

The ends are designed to use Carmer cut bars, and so a pivot is provided for such, but not included.  Yarmouth Model Works makes several photo-etched Carmer levers, which should work on these parts.  Grab iron holes are printed into the ends, but probably have back-filled with resin before the processing was completed, so those will need to be drilled out.  The brake staff holes will probably need to be cleared too.  Then a suitable staff (wire) and wheel (probably Cal-Scale) will be installed.  The retaining valve has been printed in-place, but a 0.009" wire retainer pipe should be fitted on the Dreadnaught End version of these parts.  The wood ends have the retainer pipe printed-in-place.

Bonding flange which will allow the glue to form a tight grip between the body shell and the new ends.

Pre-assembly prep on the ends is minimal, but important none the less.  I carefully make a few light passes with my mill file to remove any remains of the support contact points from the bonding areas outside of the rib.  This will insure that the part fits smoothly against the end of the chopped Accurail car body.

Chopping the Body

Two long cuts are made in the ends of the body, just inboard of the sides.

The first step is to chop into the injection molded ends, along the inside edge of the sides.  Once the cuts are made, the end is popped out.  Note: I usually only do one end of the car at a time, this allows the other end to provide good rigidity and support to the sides and help keep everything square throughout the process.

I just bend the end of the car back and forth until it fatigues and breaks loose.

Step two is to trim back the sides to remove the original corner posts.  I did part of this with the razor saw in the past, as I got a little impatient on the second end (A-end), I went ahead and chomped through the last 1/16" of sides with my sprue-cutters.  I marked the parts to discard with a black Sharpie marker, stopping just at the edge of the wood boards.  It did require some careful alignment to be sure I wasn't going to bite too much off.  

Dry fitting the A-end for B-50-13/14 'as-built' wood end.

Side view of A-end after filing is complete on 1st prototype print.

In Step three, the last 0.015-0.025" of the sides are filed or sanded down to the ends of the wooden boards.  On the roof, the lateral 'running board' support should be as far back as I trim that section.  File everything smooth and even across the whole end.  I check the progress on keeping it square and even with a regular dry test fitting of the part.

Finished prep work sanding and filing car-end.

I should note at this stage I also am sure to clean the remains of the ends down to the inside shape of the body.  The new ends are designed to match the shape of the body's natural interior.  If I cut deeply into it, or make a chamfer around the end, it shouldn't be a problem.  However, I do like to keep the structure as clean as possible.  A few scratches or even rough sand paper marks could help with the bonding, but I don't want anything that will prevent the ribs on the new end from fitting down tightly when fitted.

Inside view of bonding flange with a bit of extra ACC flowed in after primary glue pass was made.

When satisfied that the dry fitting is good, as in the ends fit tightly against the body all the way around the joined edge with the Accurail body.  I remove the end and carefully put a small amount of thickened ACC/CA type glue along the inside corner of the end and the exterior side of the bonding rib.  I extend the glue application down the ends to the bottom, past the rib, where the end will still be in contact with the car-side.

I found often it is helpful at this point to have the frame of the car in-place inside the body.

Showing how I pivoted the end into place.  This is a little trickier with the larger flanged end.

The end is then slipped into place from above, allowing the notch in the end to wrap around the coupler box, but not bond to it.  In the past I've used a couple rubber bands to hold the end in place, however if any ACC/CA glue squeezes out, then it's very easy to end up with parts of a rubber band glued to the exterior of the car!  When I built this pre-production test conversion, I just held it with my fingers on the end, avoiding the sides of the end until the glue was cured.  This took only about two minutes before I could let go and it was well bonded.  (Production 3d prints have a checker pattern on the exterior of the flange, which should allow for an even stronger bond to form.

3d printed end and rubber bands to hold them in place while the glue dries.

Another option on the bonding process, is to use larger rubber bands (I used ones from larger broccoli bundles from the grocery store), and the carefully stretch these around the car body with the underframe in place.  I usually like to add a bit of shim to the car-side over the non-ladder area, so the rubber band can't get down against the joint where any ACC could come out, bonding the rubber band to the model!

In Closing

That pretty well wraps up the list of how to do the conversion of the basic Accurail car.  This should be applicable to even factory painted models.  Pre-painting the end should be possible, although I would avoid getting paint on the area which will be the bonding surfaces of the 3d print.  

Pacific Electric B-50-13 with B-50-13/14 Dreadnought End installed, before detailing.

A few details still need to be installed; wire grabs, roof walk end supports, and brake wheel/staff.  Also on most of my conversions, it's easier to just remove the plastic stirrup steps on the model.  I'll be replacing them with standard U-shape A-Line stirrups installed.  The PE car will be getting the 45ft radii curve brake rigging modification to match detail photos in a separate blog post.

T&NO B-50-13 with original Wood Ends.

New end reporting mark decals will be needed to finish the car after the conversion is complete.  Remember that the SP standard in the 1910s-1931 were to have the ends and roof painted black or have black car-cement (aka tar) applied.  After 1931 the SP started shifting to overall Freight Car Red, and Anthony Thompson suggests that the last black roof/end cars were so painted around 1942.  So paint your models accordingly.

Jason Hill

Related Articles:

Previous modeling posts on these classes, before these ends are available.

Modeling B-50-Series Boxcars (Part 3) - Plastic Options for B-50-8, -10, & -11 class cars

Plastic Options for B-50-12, B-50-13, B-50-14 class cars - Accurail & Tichy models

SP 24864 (Part 1) - Kitbashing B-50-10 from Accurail 40ft Boxcar - Not including these parts, I'm waiting for the earlier B-50-8/10/11 ends to be produced.