Kitbashing EBT #6 - Part 2

As I mentioned in my previous post, the AHM Roundhouse 0-6-0 is reasonably close to the EBT's Mount Union yard goat: the drivers are the right size and the length is within a foot of the prototype.  Beyond that, however, there are some significant differences between the two.  Compare the following photo of #6 with the AHM switcher as advertised on eBay.

Note that the model places the bell between the forward sand dome and the steam dome, whereas the prototype has the bell between the forward sand dome and the stack.  A careful examination of the model will also reveal that the domes are quite different from those of the prototype.  In addition, the model has a pair of air pumps about halfway between the cab and the smoke box, passing through the left hand walkway.  EBT #6 had a single pump just forward of the cab.  The kit's cab is steel, while #6 had a wood cab.  And the headlights differ as well.

It was clear that I was faced with two choices.  I could build the kit more or less according to the plans and finesse the differences; or I could "cut and paste" the kit's boiler and cab, add brass parts from Precision Scale Company, and make a reasonably close approximation to the EBT prototype.  Being a glutton for punishment, I opted for the second choice.

The first task was to rearrange and replace the steam domes.  Since the domes are molded on to the kit's boiler, that required removing all three of them.  I considered sawing them off, but I was concerned about damage to the boiler.  Instead, I decided to drill them off.  Using a pin vice with a small bit, I drilled a hole from the underside into the center of each dome.  I enlarged the holes with increasingly large bits, until they would no longer fit in a pin vice.  Then I turned the drill bits manually, gradually scraping away the base of the domes until they were entirely removed.

While I was working on drilling out the molded on domes, I called PSC and ordered a set of two brass sand domes and a brass steam dome for a D&RGW K-37 (parts HO-3014 and HO-3016).  Careful measuring with a micrometer revealed that the 0-6-0 boiler was within a few inches of the K-37, which was, after all, originally a standard gauge engine regauged to 3 foot gauge.   Once the kit domes were removed, I test fit the replacements.  I found that the holes for the rear sand dome and the steam dome were just a tad too big.  Also the hole left from removal of the forward sand dome (where the bell would be positioned) would have to filled in. 

I used Squadron White  Putty to fill in the holes on the boiler.  To keep the filler from extending into the boiler, I wrapped the weight with plastic Cling Wrap and inserted it below the openings.  Then I used a small piece of thin styrene to smooth on a layer of white putty to fill the holes.

After the putty dried, I used fine Emory cloth to smooth off the surface.  While I was at it, I also filled in the opening for the air pumps on the left running board.  In the following photo the domes are just sitting on the boiler and have not yet been glued in place.

Once the putty was thoroughly dry, I sanded it smooth and cemented the domes in place with five minute epoxy.  In the following photo, the cab has been test fit and the visor on the headlight has been removed.

The cab presented its own challenges.  In looking through the PSC steam catalogue, I found only one cab that was a reasonably close approximation to the cab on #6.  It was a Ma & Pa cab in plastic  (part HO31691).  My original intention had been to replace the steel cab in the kit with the wooden version, but the steel cab fit the boiler better  I decided to keep the front and rear portions of the AHM cab, along with the roof for mechanical strength.  I used only the sides of the wood cab from PSC, carefully cutting out the steel cab sides and sliding in the wood sides, glueing them with Plastruct cement.

At this point most of the major alterations to the cab and boiler were done, and it was possible to assemble the engine to see how it all fit together.  Here I have added a "one lung" air pump just forward of the fireman's cab door and a brass steam generator, both parts from my scrap box.  There is still a good deal of detail work to be done, but already my model of #6 is a much more accurate representation of the Mount Union prototype.

This concludes the second installment of how I kit bashed an AHM Roundhouse 0-6-0 into the EBT's #6 standard gauge switcher.  In the next post I will discuss installation of the new can motor and how I constructed a styrene firebox and backhead to disguise it.  Also covered will be the installation of dual couplers on the front engine beam and the rear tender beam.