I've been doing T and M scale models for some time and figured I would share some of my tips for 3D printing handrails (and other small details) in this diminutive scale. I like etched metal but you can't do the same things with etching and the turn around for etching is pretty bad.
At this point I should point out these are printed on a Phrozen Sonic Mini 8K using an 80-20 mixture of Phrozen Aqua 8K (grey) and Prozen Onyx Impact Plus. This gives the print a decent amount of flexibility and hence durability for these tiny parts. How tiny? The handrails are 0.18 mm diameter. The riskiest part of handling them is removing from the supports (I use 0.23mm diameter supports) and remove them with a standard #11 blade. I print, wash, air dry for a day, and cure for a couple minutes--then slice away. Incidentally, when the models come out of the printer they look like wet noodles, distorted and curled. But as they dry they contract and go back to shape. That contraction can be an issue as I note below.
On the DL535, the long handrails detach as a unit with the outside of the frame so they can be printed laying horizontally. Here's why--Although I have printed handrails vertically they tend to contract and pull the stanchions "out of plumb". Printing horizontally gives them more dimensional stability for some reason. It also makes painting much easier, when complex striping or lettering must run down the long hood. Note the front and rear handrails are printed vertically on the body, and supports are arranged to keep some tension on them and keep them plumb. I suppose they are short enough to not contract as much as the long runs along the length of the body. But the supports are attached to the outside and take some care to remove the tiny "nubs" that often remain.
For the EBT caboose, the end ladders are also similarly thin--this was the first test print and based on this I am going to try going "all-in" with end railings. I also have some issues to fix with the frame and roof as well. But I like how the smokejack came out and the rest of it, generally.
As a side note--the T-scale Train Master was printed with all stanchions vertical, attached to the body. I got around the contraction issue by modeling the stanchions at an increasing angle off plumb the closer they got to the end of the loco. The railings are also thicker to take more abuse (a whopping 0.22 mm diameter) since I wanted to make them as fool-proof as possible.
To be frank, I don't like this solution as much as making the separate handrail/frame that can be printed horizontally. And some of the Train Master paint schemes really would benefit from removable handrails.
I do wonder how the new DLP printers would do with this task? Also, I have never printed models at an angle either--just doesn't seem necessary. I wonder how this would affect the shrinkage issue, if at all?
- Jesse
