Looking to Print a Caboose...

[wm3798]

Wow.  I'm certainly glad there wasn't anything more serious, but that sounds plenty serious enough!

Lee

[SkipGear]

Wide platform version is done.

[GimpLizard]

Wow.  I'm certainly glad there wasn't anything more serious, but that sounds plenty serious enough!

Lee

Yea. It was a bit scary, but it certainly could have been worse. Even a week later my nerves are still a bit on edge.

[PJPickard]

I really like what you did with the handrails. I've been thinking about this myself...I'm also working on a printed caboose.
What software are you using? Mine is limited in how you can place supports(Z Suite) I'm almost thinking of just modeling the supports.

Thanks!

[SkipGear]

I've been doing everything in tinker cad. Working on a second version of the handrails and support system for them now. I was able to cut the handrails out but it was tedious and they were still very fragile. I thickened them up from .25mm up to .35mm and added a better brace across the bottom for mounting. I also opened up some gaps where the fit together to allow for paint thickness.

I have totally given up on any auto support system for regular, geometric models. I will draw my own or use the slicer software to manually support it.

Definitely still a learning process with a bunch of trial and error thrown in. I eventually want to be able to have alignment pins and holes on the parts.

[PJPickard]

We are thinking along the same lines...I have this idea to print the interior of the caboose and add the sides and ends and have them line up automatically. More work to assemble yes, but I get better prints when I print detailed things like the sides flat on the build plate.

[peteski]

We are thinking along the same lines...I have this idea to print the interior of the caboose and add the sides and ends and have them line up automatically. More work to assemble yes, but I get better prints when I print detailed things like the sides flat on the build plate.

You are basically printing a "kit" of parts to be assembled.  Nothing wrong with that.
Actually I wish more 3D designers did that, especially with vehicle models.  Sure, 3D printing technology is capable of printing the entire model (including the full interior) as s single printout, but then how do you paint that darn thing, or install windows?  Plus, having things like wheels separate makes painting much easier.

[reinhardtjh]

I've been doing everything in tinker cad. Working on a second version of the handrails and support system for them now. I was able to cut the handrails out but it was tedious and they were still very fragile. I thickened them up from .25mm up to .35mm and added a better brace across the bottom for mounting. I also opened up some gaps where the fit together to allow for paint thickness.

I have totally given up on any auto support system for regular, geometric models. I will draw my own or use the slicer software to manually support it.

Definitely still a learning process with a bunch of trial and error thrown in. I eventually want to be able to have alignment pins and holes on the parts.

A possibility for the handrails and like is mixing the resins.  There is a strong but flexible resin called "Tenacious" by Siraya Tech.  It's not cheap ($65/KG on Amazon) but you mix it between 20% and 30% with your normal resin and it adds strength but also a small amount of give.  That is, less brittle.  The one gotcha that I see is that it's said to work best at temps 25-30C (77-86F).

https://www.amazon.com/Tenacious-Flexible-Resistant-Siraya-Tech/dp/B07PLJ9XW9

On Reddit 9-10 months ago https://www.reddit.com/r/ElegooMars/comments/eaznbp/siraya_tech_tenacious_with_elegoo_mars_should_i/

Based on this for handrails you might want to go up to 40 or 50%

[SkipGear]

I need to quit adding details and finish this thing.

[wazzou]

What was the rationale for the prototype to build a caboose with such wide platforms thus creating a steep climb up or down the steps?
I'd think that wouldn't be all that safe?

[SkipGear]

The step design is not really that uncommon, at least for B&O. The wagon top caboose had the same steps. Many C&O & N&W had similar steps designs.

I think the reasoning was that it would make the car stronger without the cutouts in the floor for the steps. These caboose were often on the back of trains that needed pushers and the stronger caboose saved time because the would not have to uncouple the caboose. They could also cut the pushers off on the fly without having to reassemble the train.

[Chris333]

So no banding in the print where the window  are?

[SkipGear]

This is a close up of the first one I painted. It's a quick print job and sloppy glue together just for test fitting but the only hint of vertical banding is along the edges of the roof and the cupola roof.


Printing the wide porch version right now, with the updated end rails and roof walks, as well as a smoke jack and hole to mount it. If these work as planned, it's a kit.

PS. I found out how brittle this stuff is, the caboose above has been glued back together after squeezing it a bit to cure a bulge in the sides created by a tight fit to the floor, and one side shattered. Once I am happy with the design, I'm going to try Gray resin. I know how the green works so I'm using it to set the model up first.

[John]

PS. I found out how brittle this stuff is, the caboose above has been glued back together after squeezing it a bit to cure a bulge in the sides created by a tight fit to the floor, and one side shattered. Once I am happy with the design, I'm going to try Gray resin. I know how the green works so I'm using it to set the model up first.

This is looking really good ..  to fix the bulging .. maybe add an internal support .. like this guy did ..

[Maletrain]

What was the rationale for the prototype to build a caboose with such wide platforms thus creating a steep climb up or down the steps?
I'd think that wouldn't be all that safe?

The original designs of the B&O I-1 and I-5 caboose had bolster spacing designed to keep the truck wheels from reaching the steps (15' bolster span).  When the B&O decided to increase the bolster span to 19' on their I-5C design, they needed to get rid of those passenger car type steps to provide clearance for the journal boxes on the trucks.  There is a statement in Dwight Jones' book about "light pusher service" for the I-5C design, so frame strength may have been an issue, as well as stability increase due to wheel placement closer to the car ends.  It was the I-5Ds that had their (steel) frames filled with concrete and scrap steel to allow for heavy pusher service.

Many of the I-1s were rebuilt to parts of the I-5 specs over the years, so had wide end platforms, even if their bolster span was not increased to 19'.  I don't know if any I-1s ever got 19' bolster spans, but some end-on photos seem to look like they did.

From an ops standpoint, these I-1s should not be pushed from the rear by helper locos used for steep grades on heavy trains.  By the transition period, they were probably only used on locals.  Of course, when switching relatively light cuts of cars, the road engines often pushed on I-1 cabooses.

When we get to the I-5D models, there are plenty of period photos with really big locos pushing on those cabooses on the rear of heavy trains - maybe a 2-8-8-2 or a pair of 2-10-2s!

(see modifications in next post)