Scratchbuilding an AT&SF Tender

(All photos copyright © Paul Washburn; used by permission)

Project Description

Paul Washburn decided to scratchbuild another steam locomotive. In particular, he is building an AT&SF 3129 class 2-8-2 Mikado. He was sending progress photos to a handful of people, including to me, the NASG webmaster. I am particularly interested in this because I want to scratchbuild a steam locomotive as well. I asked Paul if he would mind if I would share his photos with the audience of the NASG web site, and he gave me his blessing.

I think this provides a unique opportunity to see how an experienced builder goes about constructing one of the, arguably, most complex projects one can tackle in our hobby (Paul has built a number of engines and cars from scratch, some of which have photographs on this web site). This page features the construction of the tender; there is a separate article for the construction of the locomotive itself.

The Tender Body

Paul started with the 12,000-gallon tender. It starts life off as a simple styrene box. The square stock of styrene in the corners is not only for rigidity, but also to allow him to round the outside corners.

Additional 0.040" styrene was used on the interior to strengthen the body.

The tender shown next to the scale diagram Paul is using as his guide.

In the next photo you can also see that Paul rounded the exterior corners. He also added more interior bracing.

These are the tools Paul used to do the rounded corners.

The motor tool shown in the above photo was used to carve out the interior corners. This then allowed for the installation of the tender tank top.

Next up was the installation of the top trim around the tender using some 0.020"x0.040" styrene strip. This photo also shows how Paul dealt with the curved corners for that top trim. He added more than he needed, and then later filed it down to match the desired profile.

The next photo shows the completed trim. Note that the trim is over-extended to the outside of the tender body, as per the prototype.

Paul then started working on some of the end details.

The Tender Frame

The basic frame is made up of styrene with a brass spine the length of the frame. It also has a brass end beam. This will provide the drawbar pull strength of the model, a solid coupler connection, and a good platform to which to attach the trucks.

The brass spine was fastened to the main frame using three 1-72 screws. Paul also used the 1-72 fasteners to mount the frame to the body (the four corner holes shown in the next photo).

Note the side-sill styrene strips that also hide the brass frame from view.

The Tender Trucks

Paul will be using cast-resin side frames for the trucks, so for durability, he built the truck frame out of brass. This will also facilitate the installation of the truck bolsters.

The side frames are attached to the metal inner frame using epoxy glue.

Adding the Final Details

A few more details added to the body. The beauty of an unpainted model is that it is easy to identify which parts were fabricated and added to the basic body. The brass parts and wire are easily identified. All other parts were hand-made out of styrene.

The next two photos show the addition of the rear ladder, grab irons on the corners, electric conduit for the lights (along the outside, top edge), and some more pipes and fittings.

Paul mentioned that the oil bunker on top of the tender is attached with a couple of screws. This allows him to remove it later to be able to more easily apply the rivets to the oil bunker.

Finalizing the Underframe

With the next set of photos, Paul shares the work he has done on the brass parts of the underframe, and the end sills.

Applying Rivets

Paul highly recommends using the Archer Fine Transfers rivet decals. The photo shows the ones he used for the tender.

For fixatives he uses Walthers Solvaset to settle the decals, and then, when finished, over-sprays them with Alclad II Klear Kote Matte ALC 313.

Here are the rivet decals applied to the top of the oil bunker. He marks out their location with a ruler and a pencil, and then lays the decals to that line. Note that you can make out faint lines going across the bunker, too, so that rivets match each other on the other side as well. A ruler and a razor blade were used to cut out a line of rivets from the Archer sheet. These decals do require a lot of patience, so his recommendation is to take your time.

The sides of the oil bunker get the rivets, too.

Adding the rivets to the hatches and their hinges.

The tender body gets the same Archer rivets treatment.

Note the rivets on the end of the body.

Phillippe Cousyn had Shapeways 3D-print the front steps and the toolbox for the tender.

And, here is the tender completed.

References

12,000-gallon tender side profile drawing

Prototype photo of 12,000-gallon tender

AT&SF #3158

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