Getting GOing again on a Project

I haven’t worked much on the first test of the Hawker Siddeley single level GO car since last fall.  The discovery of the CAD error in the first print in October (see here) has kinda set me back, as despite the quick fix in the 3D computer model, I haven’t really felt like spending the money to re-print the first sample body until I was certain any other issues were found out.  For now and for me, for my first sample and the model that will be in my collection, for the moment, I can live with the wrong window radius.  This weekend, I finally got off my rear end and said I’m sick of looking at the half finished bits of this car.  Lets actually paint the fine details, and look at what needs to be done so the car is presentable.  Ordinarily, the upcoming Barrie-Allandale Train Show on the February 17-18th would be cause for motivating me to have had it done, but the Toronto Railway Museum isn’t able to attend the show this year, so my models won’t be out on display.  Their next major outing is likely now Doors Open Toronto at the Roundhouse on May 26-27.  That gives me more time for getting any parts I discover I need, but to figure that out, I actually need to work on it.

IMGP6672RawConvTinting clear styrene window strips with Tamiya Clear Smoke paint. It looks better when done and dry than this mid way though shot makes it look.

With the window error, and this being the largest 3D printed body I’ve designed, along with a completely 3D printed interior and underbody, there’s lots of learning experiences in this project. Not only fit and clearance to make sure the parts still fit when assembled and things like clear window glazing are added, but making sure you can even do things like finish the car and assemble it and have it run.  It has all fallen down on the have it run, my first attempt at 3D printed trucks are to be kind, garbage, but as they are easily swapped out, the only thing really keeping me from moving forward was myself.  I’ve also discovered some parts of the body and underframe have warped over time, even with the strengthening brass in the frame.  This is something I’ll need to examine more, though the longer I have looked at and worked on the car, I suspect that if I ever manage to bring it to the market, it will be by using the 3D prints as masters for resin castings, not as a fully 3D printed car.  The 3D printed material is just posing too many issues for something of this size thats designed to actually run on your layout.

IMGP6673RawConvMagnets to hold the body and frame together and in alignment. A trick I learned while designing D-1, but taken from an Athearn/Roundhouse coach I was using for parts on that project.

The two biggest tasks were installing magnets to hold the frame and body together, and finishing the windows.  The Magnets are 0.125″ diameter round magnets, that are set into circular openings in the frame and body prints and held in place with CA. I’d use epoxy, but I have concerns with the bit of heat it generates as it cures warping the 3D printed parts, CA doesn’t have this side effect.

For the windows, it was a slow and steady couple of hours lining the window frame gaskets black, then inserting the windows with a smoke tint.  One thing I realized from this is the full interior gets lost with the smoke.  This is good for the future as not having the interior would reduce the cost of the 3D prints substantially.

Progress on GO Cab Car 104 as preserved at the Toronto Railway Museum. Need to sort out the cab stripes, then I can finish the front end details.

At times today, it felt like every two small steps forward I took, I took one big step back.  It took four attempts at figuring out how to get a number board into place in the cab.  I’d designed them thinking I could light them.  Same for the headlights above the cab.  Both of those have been non-starters because of other design decisions in how the pieces went together, that whole learning by doing with the 3D designing of models I mentioned above.  For future prints I’ll be making some changes to the design of the interior to leave more clearance for fitting it in when the windows are glazed, and to make installing the number boards a bit easier.

I also discovered that somewhere along the line, I ruined the screw holes for mounting the couplers.  That resulted in me having to go at the front end of the car with my Dremel to drill through the brass bar that forms the spine of the car to let me create new mounting holes for the coupler screws.  It worked, but only just barely was I able to create new holes and tap the brass bar enough to take the screw.  Again, this kind of error doesn’t hurt as bad on my car that will likely never run on a layout, but I need to sort out what I did wrong in the design to make sure someone else doesn’t have that problem if I sell them a print.

All in all, despite many frustrating setbacks, I managed to advance the model a lot.  I certainly know some spots where I need to go back to the 3D model and make adjustments before any future prints of parts of the car are attempted.

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