Well, I’ve had numerous setbacks on my locomotive building enterprise (which between that and work have left me too busy to post) including two today, one of which I have recovered from but the other I have not.

Has anyone used Blacken-It on a brass chassis?  I had paint peeling issues, with the paint flaking and getting into the gears, so I figured I would blacken a new chassis, it’s an external frame anyway, so unlikely to been seen as long as it is not bright brass.  It turned out great, and still looked and worked great the next day.  But a week later, disaster – the steel axles are all rusted and bound up in the brass axle holes (bearings).  I figure it’s one of two problems, moisture from the last 915 alcohol bath (and I hadn’t yet oiled the axles) or galvanic action that is catalyzed by the blackening agent.  I don’t think it is moisture since I routinely use the ultrasonic bath. Has anyone seen this phenomenon before?

On the good side I do have two chassis running, one of them seems to be doing well.  Lots of lessons learned – I’ll have to go back and update the blog soon – probably none of which would have been made by more experienced modelers. 

But, on to another project that seems be making progress and is more fun!

Chama Sandhouse Tower

At last year’s Amherst Railway Society Show in Springfield, MA, I was thrilled to see that Banta Modelworks came out with a Ridgway sandhouse kit in N scale.  It’s an excellent little kit, laser cut plywood, nicely done from what I have seen so far. The only disappointing part of the model is that it is of Ridgway’s version, which doesn’t have a cool sand tower (I doubt that was lost on the workers who shoveled it by hand into the engines…)

So I pulled out my Chama sandhouse plans and put together a 3D CAD model of the tower, and sent the prototype version to Shapeways to see how their new high resolution FUD would print it.  Fortunately it was printed, even with large stretches of just 2x6” scale boards and the detail was very nice. A photo of an unpainted prototype is above, and one of both two prototypes is shown below (one painted, just the tower, and one unpainted with support structure}along with a partially built Ridgway sandhouse.  I have about 7 changes to make, but based on the prototype I am very confident that this is practical with high 3D print yield, and it’s not too fragile (it’s actually quite flexible.) The 3D resolution is not perfect, but there is noticeably less was on the casting and I’m thrilled with Ultra detail. I still need to figure out how to model the down spout (probably just a wire) and valve mechanism.

Thanks to the Quick Pic Books, I noticed something not in typical photos or drawings that I’ve always been puzzled about – there is an air cylinder on the side of the sandhouse to move the sand to the top of the tower – filled by the engines that stop for sand.  Neat, I can make a 3D model of that as well.

A reasonable Chama facsimile could be made from the Banta kit, but I may 3D print the sandhouse as well to see if I can do building walls effectively (may be more expensive that laser cut plywood).