Notes for 2002 Naperville Proto Meet

Notes for 2002 Naperville Prototype Modelers Seminar

“Superdetailing Hopper Cars” - John A. Spencer

Construction sequence:

Do all work on body and frame separately before bonding together.

Replacing cast-on hopper grab irons:

This is the most visibly effective modification you can make on a hopper model.

Tools:

Microchisel - 1/16” (corners softened).

Fine chisels made by snapping off tip of dental drill and grinding on a stone.

Scraper – short, stubby angled blade ~1/8” edge (e.g., Grifhold 24-E).

Needle in handle for centering drill holes. Keep sharp on a stone.

#79 or 80 drill in pin vise.

Cutter- narrow tip (e.g., ModelExpo JP13A or equivalent).

Nominally 1/16” cardboard! (For polishing.)

Spacing gauge – 0.030 stock corresponds to 2-” AAR safety standard.

Pliers - narrow flat-nose.

Method:

Cut off surface projection of cast-on grab keeping fastener intact with microchisels.
Keep bulk of cast-on grab in place for support while drilling.
Center for holes just below each fastener.
Drill #79 or 80 – clear through if you dare.
Nip out the remaining cast-on grab material; be careful not to stress thin parts.
Carve off and generally smooth all the cuts. On surface molded grabs carve very close to flush then scrape down. On unpainted models fine sanding can be done if desired (down to ~600 grit, wet). Finish off by polishing the surface with the end of a freshly cut piece of ~1/16” gray cardboard used on-edge.
Wait to install grabs until after finishing any brake rigging, etc. requiring access.
Grab irons - commercial or jig bent (scale thickness (0.009 – 0.010”).
Clean and pre-blacken grab irons for best glue and paint adhesion.
Cut lead length suitably. If accuracy is required, e.g. hopper corner ladders, a cutting guide can be made by drilling a pair of holes in suitably thick styrene.
Test fit for width and adjust if necessary for a comfortable fit in holes.
Apply a drop of thinned contact cement to each shank then insert.
When a row is in place, slide the spacing gauge under all grabs and adjust alignment. Contact cement allows easy adjustment while it still holds.
Carefully slide out the gauge and recheck alignment – sight down the line.
ACC from behind if feasible. If front applied be ready to blot the excess.
Adjust parallelism with flat nose pliers.
Trim protruding wire on the inside. Leave a little on visible interiors to depict the backside of the fastener.

Stewart 1935 AAR offset triple hopper subside sill modification:

A substantial percentage of the offset triple hopper cars were built with a straight side sill between the bolsters with a corresponding tapered member stretching to the end sill. This design is shown in AAR Mechanical Division Plate 601. The Stewart model depicts the cars with the drop side sill and level end members. Changing this to the straight side sill is fairly simple. Stafford Swain described a method for CN hoppers in Mainline Modeler, May 1997, page 36. This method differs somewhat. It can also be used on the Athearn offset hopper.

Cut out a full notch down almost to the level of the side sheet in the tapered area.
Remove the excess side sheet length.
Using a fresh razor blade (zero kerf), cut the subside sill from the main side sill.
At the right end, also cut the base of the ladder stile free from the side end sill.
Use a pair of flat nose pliers to gently stress the cut subside sill downward.
Install segments of EVG 2x8 stock in the notches - ends flush with cut.
Bond the subside sills even with the bottom of the 2x8. Pro-Weld is good here.
At the right sill, add a sliver of 0.010”x 1.3mm wide to the base of the stile.
Trim, scrape and sand as required.

Hopper end vertical support modification

As with the side sill variation, many of both the twin and 3-bay hoppers used vertical angle iron end supports that extended to the top chord. The Stewart model conforms to the original 1935 AAR design as shown in Plate 601. There are several ways to modify the Stewart model. The simplest approach (“layout quality”) is to cut out the kit supports, smooth the residuals on the body and use EVG or Plastruct angle stock. A more accurate technique is to fabricate a nominally 4 x 3 angle with EVG dimensional stock. This neglects the rivet detail on the car end. The third way is to use an embossed Mylar strip for flat leg of the angle and an edge bonded EVG 1x3. You can re-contour the existing vertical member for support. The method used here, since I plan to build a considerable number of these kits, is to create a pattern using embossed Mylar and EVG stock. There are several advantages to this approach. You only need to put the extra effort into making the parts once. The castings can be made with embedded fine gauge wire for strength and they can be cast in a color that nearly matches the kit paint. The pattern was made flat on a small sheet of styrene. Open face polyurethane castings were made with 0.008” brass wire tucked in before the resin sets. A mix of 1:1 Raw Sienna to Burnt Sienna dry color pigments was added to the resin before mixing. To get a more intense color casting, you can dust the mold with the pigment.

Slope sheet braces

This is a common omission on most commercial kits and clearly an important visible feature. Richard Hendrickson described a method for modeling this feature in his article in Railmodel Journal, August 1995, page 16. They can be fabricated as shown on flat 0.010” sheet stock with EVG 1x3 placed on edge. Cut out the center open area first, then trim the outside angles. The top ends of these angles are tapered (not shown on the figure). Bond the transverse angle to the slope sheet bottom 30” down from the end-bottom edge. For the Stewart hopper, the wedge block at the bottom needs to be trimmed at an angle before installation. The part is bonded to the body end sill with sufficient space to allow the frame end sill to fit in place.

Top chord gussets and fasteners

There were several different patterns used for the angle gussets along the top of offset side hoppers. Clear photographs are needed to define this detail. At least three different arrangements have been observed:

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The incorrect gussets (*) were cut off with a microchisel. The paint was scraped on the opposite side. New triangular gussets cut from 0.010” x 0.040” styrene ~5.5mm long were solvent bonded. When set, the outside corners were chamfered slightly with a scraper to better match the originals.

These gussets were also riveted to the top chord. This can be simulated by pressing a sharpened #24 gauge syringe needle tip centered on the same line as the side gusset rivets and slightly outboard of the top chord centerline. Making a template with a slot that fits the gusset angle can do this more precisely.

Hopper bottom width correction

Examination of AAR Standard drawings reveals that most hopper models have a width at the bottom of the bay that is too narrow. The Athearn twin is a notable exception. Prototype hoppers are nominally 7’-8 across the bottom whereas the Stewart model is only 6’-11. Compared to prototype photos, the hopper bottoms on the model slope inward too much. The model was corrected by adding cast extensions that include a facsimile of a Wine frame and lock. Rectangular door castings were also applied.

Embossed Mylar underside details

Slopesheet cover plates, bolster and crossbearer caps were drafted with Corel Draw in proper size to apply to the hopper bottom. The figure to the right is reproduced correct size. To use, make a 1:1 copy onto laserprinter transparency film. Emboss and score before cutting out the pieces. The faint lines are used to align rivet rows for use with a rivet embossing tool. Note that the hopper bottom sheets were drawn with a little extra width (8’) at the tip. Adjust for the use with your specific model. NYC 9004007 was built with hopper side extension castings that correct the overall width.

Top chord corner gussets

Hopper top corners were reinforced with riveted gussets. The figure at the right is correct size to copy onto film and emboss. Sand the cast-on corner irons flat and apply the embossed part. When solidly attached, sand into final shape.

Drop grab irons

A simple bending jig can be constructed from styrene stock as show in the figure to the right. These dimensions yield a drop of ~2-”. Add more holes for other length grabs. The drop bend can be made sharper with pliers.

Brake rigging method

The ’35 AAR design floating and intermediate levers are 13 x 13 and the cylinder lever is 19 x 30 (model used 22 x 26). The underside levers are nominally 3’-6 from the bolster centerline. Install the floating lever fulcrum (embossed/folded/drilled 0.003” mylar). Clevises are cast in flat mold made from Cal-Scale AB-283 cylinder clevis as a pattern. Cut off the shank and use the ‘U’ part. Install properly oriented clevises on the brake levers with thinned contact cement (1 CC : 1 toluene). Drill #80 for a 0.010” fulcrum pin on the floating lever. Cut appropriate lengths of blackened 0.010” brass rod for top rods and make a ~right angle bend. Drill center sill #80 inboard of the bolster. Trim the top rod length to the lever. Make the lengths appropriate for brakes in released configuration. Install the floating lever in the fulcrum with a drop of contact cement on the pin. Clevis shanks are ~2” segments of 0.024” OD wire insulation (salvage from excess grain-of-wheat bulbs leads). Dilate the insulation on the tip of a straight pin and slip on the end of the rods. Contact cement the top rod in the drilled hole. Apply a drop of contact cement to the end of the floating lever clevis and a drop to the insulation shank on the A-end top rod. Tack the rod and clevis together. Adjust alignment while the cement is pliable. Apply a little MEK if the joint gets too tight. Locate the intermediate lever (or cylinder lever on house cars) and cut the main rod to length. Join the B-end top rod to the lever and then the main rod. At this point the whole system is flexible so it can be adjusted (posed) as desired. When everything looks right, apply a drop of ACC to all the joints. Add angled top 24” safety guards per standards.

Reweigh stencils

Steel cars – Pre-1949: every 30 months. Post ’49: 30 months first time then 4 years.

Accurail® Proto:HO AccuMate® E-Type couplers

Remove excess length of the center sill outboard of the bolsters. The ORER “Outside Length” is the distance between the striker plates. Calculate the required length of the Accurail draft gear as half the difference between the outside length and the revised center sill length. Trim the back of the draft gear to length. The outboard 0-80 screw can be avoided by installing a segment of 1/16” styrene rod cut flush with the surface of the bottom plate. Use the 0-80 screw in the rear. This allows the coupler maintenance.