Cool!

Love the diamond stack, Dave...a great improvement!

Are you going to use Kadee N scale couplers on this and your cars?

Couplers

Thanks, Verne. I haven't really decided on the couplers yet but I'm actually leaning towards link and pin for the On18 stuff.

New Stack

The new stack looks a little better with a coat of primer on it. It's a snug press fit atop the original stack and will remain removable so that a canopy can be installed.

Next I'll primer and sand the body, then add some weight inside the boiler and water tank. I won't be adding a decoder at this point (not sure where it would fit!), but the body will remain removable to keep that option open in the future.

Adding Weight

The Kato 11-103 mechanism is a pretty smooth runner, but as with any 4-axle locomotive, the more weight over the wheels to improve pick-up, the better.

The 3-D printed body weighs next to nothing as is. Fortunately it is also completely hollow, making it easy to add weight to the interior of the boiler and the water tank. I chose to use the old shot-and-epoxy method.

First, it was necessary to fill in the cut-off stack to keep the epoxy from leaking out. To do this, I heated a short piece of plastic sprue with a lighter, effectively melting it into the opening.

Next I poured in about 1.5 oz of BBs. I chose BBs because their small size would fill as much of the void space as possible.

The last step was to mix up about a thimble full of 2-part epoxy and slowly pour it over the BBs. I used Envirotex Lite because I had some handy, but just about any pourable resin would do.

The resin was added just a few drops at a time, letting it sink down and settle around the BBs without overflowing. I'll let that cure for about 24 hours before going on.

Priming and Smoothing

Fresh from Shapeways, 3D printed parts can be a little rough. The body for my critter was printed with what they call "Strong White and Flexible." It's a polyamide nylon and the results have a rough, dusty texture like 500 grit sandpaper. ABS plastics can be smoothed with an acetone vapor process but that won't work with this type of plastic. After searching high and low on the web, I finally came across a simple priming and painting technique that would deliver results that were good enough.

The first step was to clean the piece thoroughly with a wash of 70% isopropyl alcohol.

Once that dried, I affixed some masking tape to a piece of cardboard, sticky side up to hold the piece, then took it outside for painting. I used satin black Krylon Paint with Primer for Plastics. Like any primer, it contains particulates to help fill in and smooth the painted surface.

The idea is to spray it on fairly thick. The material is very absorbent so it takes several coats to get a decent finish. I applied the first coat, allowed that to cure for 20 minutes and then applied a second coat. I did not sand between coats. The point of this technique is to smooth the surface without taking away the delicate printed detail. Here's how it looked after the first 2 coats:

You can see how much of the paint has been absorbed by the plastic. A third coat was added 30 minutes later, and then a fourth coat an hour after that. A fifth and final coat was applied 5 hours after the fourth. Each successive coat helps to smooth out the surface. Here it is after 5 coats:

Not perfect, but a much smoother surface than what I started with. This will work as a base for final painting and detailing.

Super glue

I watched a video where someone making model car parts just painted on super glue with the nozzle of the glue and then smoothed it around. Then he sanded it and it's nice and smooth. You can prime with regular paint after that.

I saw that one too. I think

I saw that one too. I think that would be a good solution for some smaller printed parts. I wanted to give this "no sanding" technique a try.

Yes

I think it was a pretty small part.

Paint

The corporate colors of the Calico Gold Company are gold and green. Today I masked off everything but the water tank and bunker and then sprayed the model with a satin finish enamel called Hunt Club Green.

There's just a little bit of over spray to touch up but so far, so good.

Next I'll be getting to work on the cab.

Nice!

Great job making the job of smoothing those rough surfaces without a lot of frustrating sanding! I like the green and black...will look pretty snazzy pulling that cute passenger car in the background! 

Lookin' good!

Coming along well, can't wait to see it with more details! Are you going to put some controls and levers in the driver's end, or keep the interior simple? 

Controls

Thanks guys!

Yes, I'll be adding as much backhead detail as I can. I need to figure out a firebox door to the boiler, then add the necessary steam piping, gauges, throttle, brake lever, Johnson bar, etc... The trick is finding details small enough. Even some HO stuff is oversized for this critter.

You can always try scratch building...

I bet that some wire could get you pretty far in terms of piping and stuff, and you could always try fashioning your own parts out of odds and ends.

Firebox and Throttle

Scouring my scrap boxes for parts, I came across a body shell for what I think is an old HO MDC Consolidation. The overall backhead was much too large but I saw that I could cut out the firebox door and then scratchbuild a throttle valve.

I cut out the firebox door with a razor saw and then used some 220 grit sandpaper taped around a thick marker to sand a curve into the back of the piece.

Next, I cut off the HO throttle and made a new one from a paper clip. I drilled a hole with a #61 bit to receive the new throttle.

Now it was time to paint the firebox flat black. While I was at it, I masked off the green parts of the body and went over all the rest of it with flat black too.

I wanted to add some fancy brass bands to my boiler. I cut 2 bands about 4 scale inches wide from some brass foil. I taped this down and then coated one side with 3M 45 All Purpose Spray Adhesive.

Once the glue was tacky, it was then a simple matter to apply the bands to the boiler like tape. After that, the new firebox and throttle were glued in place with gap-filling ACC. Here's how the critter is looking as of this evening:

A Shorter Stack

After staring long and hard at the model, and getting a comment on another forum that reflected my concerns, I decided to cut a scale 12" from the length of the stack. Makes much more sense for a mine locomotive and reduces the exaggerated "cartoony" look. I also applied some decals today and I must say that the "Walter Knott" is shaping up to be a rather elegant little critter.

The gold water slide decals were custom printed from my designs by Stan Cederleaf. They were applied using Micro-Set and Micro-Sol to snug them down to the painted surface.

Thunder Mesa Website Update

Today on the Thunder Mesa blog, I bring the entire build up to date so far: http://www.ThunderMesaMiningCo.blogspot.com

Here's the Walter Knott, fresh from the paint shop and on its way up the line to Calico for final outfitting.

Looking Good Dave

Hi Dave,

Nice photo, Your #2 looks good in transit and your finishing is excellent, Hey its narrow gauge and gold mining, What's not to like?

@ Dave

In that desert heat I hope it gets a roof to provide some shade from the glaring sun.  If you don't some engineer is going to add on his own made from ugly, used and rusty corrugated metal on a couple of crooked poles.  You know what would look cool?  If it had a canvas roof over it.  Something in a vanilla folder color, but looks like canvas.  That would go good with the green!  Wait!  It would need to be fireproof!  Unless you got a spark arrester on that thingy.  Maybe the taller stack was the way to go after all.

Den

Roof and other details.

Thanks guys. I'm still thinking about a cab and roof. If I do add one it will definitely be open-air. I started on a wooden cab but decided it was impractical. I'll probably mock something up in paper first to see what will work.

In the meantime, I added a little more interior detail in the form seats for the operator(s) and an "oak" floor for the bunker. Both were made from 1/16" scribed siding stained with Minwax pens.

Not much room in here! The operator will basically be sitting on top of the fuel supply.

Short range coal supply

So Dave,

Just another excuse for a few lean-to's (4 poles to hold up a corrugated iron roof) scattered around the mine site with a sack or 2 of coal under the tin roof? Probably next to the watering points and maybe at one or two other spots at the mine? Or maybe even just a judiciously-placed wheelbarrow of  coal?

Small Coal Bunker

Maybe a small coal bunker hanging over the rear coupler similar to the one on this engine:

I'm glad

...others brought up the height of the stack, Dave. I hate to say anything about someone's kitbashing/imagineering work.

But now the critter looks like more "critterish" and less like something out of the Toonerville Trolley genre!

...

I went looking and found an image of what might be the prototype...

http://www.dyxum.com/dforum/show-us-your-railway-pictures-2_topic67262_page14.html

From the description:

For those who have issue with the original stack...

But i think it came out really well, Dave.

Original stack

Oh, I liked the original stack, I just wanted something a little different. Thanks for posting the pic! It gives me some ideas for the top of the boiler. I've got a blue enamel coffeepot that might be perfect up there. I like the placement of the wooden toolbox too.