2 Foot gauge tractor loco in 1/16th scale

[Ray Dunakin]

Nice! I love the paint on those wheel centers, looks very much like old, greasy metal.

[finescalerr]

Glad you had some time to model. Adequate. -- Russ

[Hydrostat]

Nice! I love the paint on those wheel centers, looks very much like old, greasy metal.

Ditto. How did you achieve that look of creeping oil/grease residues at the wheel's back side and for the build up grime and grease? This looks very good, Chuck.

Volker

[Chuck Doan]

Thanks!

I first did a coat of Krylon flat black primer, followed by Vallejo Model Air Burnt Umber airbrushed on. Then a thin coat of Polly Scale Grimy Black. Then I applied a mix of Mig pigments, rust black and tan. Then I added a mix of brown and black oil paints and fine powdered dirt to the face. Based on reference pics, I added some "grease" seep thru to the slots and a bit on the farside. The pigments wicked up the oils in a surprisingly pleasing fashion. Still seems to be visible after a couple of days of drying. Happy accident! I think the oil paints are going to work well for grease, just have to allow plenty of time to dry.

[lab-dad]

Looking good.
How are the printed parts working out?
I emailed you about painting mine, may be I have an old address?

Marty

[Chuck Doan]

Sorry Marty, I was out of the office last week. Clean them WELL. I use Acetone and then a good soda-blasting. Then Acetone again. Any residual wax will leach through paint and eventually cause a sparkly powder to emerge (It brushes off, but that assume you can reach it with a soft brush).

I have been using Mr. Surfacer spray can as a primer. The grey and the 1500 black work well and seem to be durable. I have used Vallejo acrylic and Polly scale with no problem as a top coat. I'm sure enamels will work too, but I don't know if the Mr. Surfacer is a good base for enamels (kinda hard to read the can).

Epoxy and ACC work well for bonding.  

Hope that helps some!

[TRAINS1941]

Great to see you working on this again.  Beautiful job on those wheels.

Jerry

[Chuck Doan]

Got the running gear parts primed. Had some setbacks with the painting before, so hopefully it will go better this time.

[TRAINS1941]

Good to see you making parts again.

They kook great.

Now just keep going with the updates.

Jerry

[finescalerr]

Please find time to work on this model. I, and probably everyone else, will be fascinated by your progress. -- Russ

[lab-dad]

That's sneaky doing the wheels and treads separately...
Why?
What happened with the paint? Was it a FUD issue or just a paint issue?

Oh, and we need to talk about your 1/16 gas-pump and pastels........

-Marty

[Chuck Doan]

Originally I was going to make the tires steel (or rather have someone turn them for me) for the look. But then I decided to try printing them and see if I can get a steel finish I like. So the steel option is still open and that's why the parts wound up separate.

The issues have been with the FUD wax and the sparkly powder. I thought I had cleaned them well, but the powder leached thru. Twice. It takes about two weeks for it to start to show up. I have had mixed results; some parts clean fine and never show sparkles. I am beginning to think some parts may be more porous than others.

[Chuck Doan]

Well, it's almost the end of November and I have built almost nothing this year. But the summer has ended, the yacht is in dry dock, and the pretty girls have removed their thongs and put them away until the spring. And so, back to the modeling grind.

I seriously underestimated the frame for my loco. The 3D printed frame sat all summer with the tractor perched on it in the hottest room in my house. All seemed well, but once I started cleaning the wax off, it began bowing and yawning enough to convince me the FUD material was too unstable to use. It was also a fair bit undersize to my 3D model, almost an 1/8" short and a 1/16th inch narrow.

The prototype uses C channel structural steel, with no thick cast sections often found in small loco frame design. The die-cast tractor weighs about 3/4 of a pound with the wheels removed, so I needed something thin yet strong to support it.

Earlier in this topic, David Fischer offered to assist in some casting, so I contacted him to see if I could cast the frame pieces. He expressed doubt that they would be stable enough in the thin sections required. He recommended building the frame up with individual pieces of styrene and metal for greater rigidity. This seemed more work than I wanted to do, but eventually he convinced me to give it a go, and this is what I am doing. I'll write it up in detail when I get more time.




Here are the side frames in primer for flaw detection. I go through many prime and strip sessions.






I attached the frame sides to the journal pedestals yesterday. I hung a few other parts on to get a feel for it. The end beams seen here are printed, but I will be making styrene versions. The FUD material is too unstable in these thin profiles. (The toothpick will be painted and weathered in the final model)

Thank you David, for the assistance! What a Forum is all about.

[lab-dad]

Im curious, likely too late but why not do the frame in steel?
Would be easy the shear and bend up.
Looking good none the less, glad your back from the yacht and babes.
Mj

[Chuck Doan]

Maybe easy for some, but I have virtually no metalworking tools or skills.  I used K and S brass strip, plus a smaller strip to get to the correct height. I am well behind the many ace fabricators on this forum. But one does what one can.