This is a short follow up on the original 3D Printed Casting “Mock Ups”. Considering the length of the original post, that’s an understatement. But sometimes it’s necessary to fill in the blanks when progress is low and discouragement is high.
Even though progress has been slow, it’s actually been beneficial in this case. The original design is based on our “fleet” of Bachmann passenger cars, literally dozens and dozens and dozens of them. Some modified with our Passenger Car Lighting systems, some still sporting the original 9V battery twin light bulb version. All of them suffering from flimsy, rubberized plastic handrails.
I wouldn’t mention those handrails except we’re talking about 3D printing. What better replacement for plastic than plastic? Well, metal for one. Brass to be exact, but then we’d need jigs for bending the brass to shape, most likely 3D printed as well.
Design “Flaws”
Just like those original handrails that failed the test, so did our original casting design. Well, at least the mock up did. The first flaw was discovered when first fitting the 10′ diameter curved track section. A redesign doubled the number of segments to better fit the curve. This was discussed in the first installment and it works quite well.
The next “flaw” is genuinely a “new” one, as in there’s not enough clearance for the new USA Trains Heavyweight passenger cars. And before you ask, no, there are not dozens of them. But there is a decade of them. There was a bulk deal on ten of them around Christmas time, so I pulled the trigger, as well as ordering a pair of F7 A-B units for A-B-B-A running.
They’ve been packed away since then, awaiting completion of all these “infrastructure improvements”. After unboxing one of them to test with, it was readily apparent the design was too narrow for these behemoths. The car is longer than the mock up! The wheels just fit on a single curve section though.
The steps and the equipment boxes both will interfere with the platform or the capstones. Back to the drawing board! It took some doing, and some days to do it, but I managed to add a “crude” approximation of the new passenger car to the mock up design.
Back To The Drawing Board
The test fit also reveals a flaw in the “track trough”. Not sure where I picked up that fault, but for whatever reason, the track is sitting proud of the platform rather than flush with it. To give an idea of how the prototype fits together, most platforms are slightly higher than the track, by about 4″ (10cm). In scale, that’s roughly 1⁄6″.
I figured giving the equipment that little bit of a height boost would hopefully compensate for any errors made while measuring their dimensions. Looks like I worried about the wrong measurement errors. Add that to the list of things that need fixed.
I’m back and forth with whether to try to forcibly disassemble the mock ups or just print all new pieces. I say try because the chemical solvent I use to cement the plastic pieces literally melts the two together into one part. Printing all new pieces is going to take a lot longer.
Each 4″ x 7″ retaining wall segment takes 4½ hours to print. Two of the pillars that join the wall segments take 3½ hours. An 8″ long track trough takes 5 hours. It should have been obvious when the curved track trough only took 3½ hours to print.
Anyway, these flaws are certainly obvious now. Not to worry though, the entire reason for all these mockups is to find the errors and flaws before they’re cast in stone, er… concrete.
Time Is Of The Essence
Alright, being overly dramatic, but time certainly is the essence of the conundrum. As in there is not enough of it to get ahead of everything that needs done. So little to do and so much time… Strike that. Reverse it.
Some say if deadlines are not set, they’ll never be met. Tell that to hurricane Debby. Now instead of spending time moving closer to the goal of running trains, it will now be spent preparing for a hurricane.
Retract the SunSetter™ awning. Stash any loose items that will blow away, like lawn chairs and cushions. You get the idea. Now add to that the garage where those items are usually stored is still the disaster it was right after the A/C decided to leak all over everything.
Progress is slow, but progress is progress. The large empty storage bin that used to sit in front of the table saw because there was no place else to put it is now filled with HO scale items that used to occupy a slot on the bookshelves in the office. It will fit beneath the work cell, taking up the wasted space under it.
Next Steps
Immediate steps are hurricane preparation, like dumping the work cart full of dirt at the end of the driveway where it has washed out around the apron and sidewalk, then retract the awning so as not to create a cart full of mud.
Beyond the immediate, back to the drawing board. The track trough and curved section redesign has already begun, old hold temporarily to prepare for Debby. I don’t like leaving the 3D printer sit idle for any length of time, but short of printing more 4″ x 7″ retaining walls, it will have to wait for the new part designs.
The big ticket item is capturing the step by step process for actually creating the station platform from all the separate cast pieces and how to create forms with them for a concrete pour. So far the mockups have captured segments of the final product, but not the process of creating those final products.
The garage needs a few more items completed before it’s ready for casting concrete patch into those retaining wall panels. There’s a stud space or two where the sill plate is totally rotted that could use a new chunk of 2×4 before setting the table saw in front of there.
The new shelves are already installed but need some thought put in to organizing what should go there and what will fit. All the things that haven’t been used and won’t be any time soon were thrown out to make more space.
It continues to evolve, like the wall cabinet for electrical items expanding to occupy two cabinets. Next is going through that cabinet that has all the “might be useful” items for the model railroad, ripe for harvesting more trash that will never be used.
Long Term
Long term is 3D printing with PETG, a more suitable material for use outdoors. Definitely more heat resistant than PLA. Not sure about its UV resilience, but paint can mitigate any shortcomings there.
The first designs will be concerned with ties and insulated split jaw parts. The originals printed in PLA lasted about ten minutes before they started to melt and deform in the Florida heat. Those stainless steel rails get mighty hot in the sun!
Next will be structural items, like window and door frames, “gingerbread” decorations and supports on buildings, etc. The ultimate goal is to create our own switches and turnouts, custom fit to the needs of the Barkyard Railroad.
Stay tuned. Much more to come.