looking at his stuff - for Z it's remarkable.
Clearly under the Shay it's a Rokuhan drive, and while they are well made and inexpensive, it you ever wanted a 200mph Shay, there you go. That's why I had to put gearheads in my Nn3 kits with those same trucks. The 70-tonner looks like it has a FUD or plastic frame.
The 44-tonner and the Shay appear to be cast brass bodies, the 70-tonner is FUD with etched parts. Good parts, just not cast brass.
And of course, they aren't 'printed' in brass, they are doing this as a lost wax print, casting it in plaster, melting out the wax, pouring in brass, which is why it's so expensive. I looked at the Shapeways design guide for this and wow, I thought regular FUD was complicated. Lots of design issues on getting the lost wax out.
I guess it depends on what you're good at, CAD or working with materials. I'm old-school enough I still like working with tactile materials and parts. And stuff goes horribly wrong with CAD, figure you're going to need 1-2 test prints of that shell and THEN finally run it in brass when you get everything right.
The process of getting a boiler 'right' on a frame and getting the end result to look 'right' on an existing chassis is not easy. Proportion is everything, and how and where you compromise is as well. On yours, with a slightly longer wheelbase, if you keep the boiler length right, it's got to go somewhere. It would look like you'd set everything off the front drive axle dimension behind the cylinders and let the extra 18" go toward the cab, then shorten up the trailing truck distance. If you can get the boiler diameter and height 'right' on the mechanism the rest is easy, but getting that part on an EXISTING chassis to fit around everything. If you just stretch the entire boiler it won't look right. With that Fleischmann, you also have that big motor in there that's right in the firebox area to design around for clearance.
On the 2-6-0, the cab didn't look right, I ended up taking a foot off the bottom and redoing after I did in-process photos. On the D16 4-4-0, it was a real battle to get the brass tube boiler low enough so the centerline of the boiler and the overall height was spot on. The worst was the Jamco 4-6-2, the model boiler was almost two feet too high, I took it all off the cylinder saddle only to find out the valve gear was whacking the boiler....got that, finally looked right, but that's what you go through on these. Making a precise CAD model means you have to work around your mechanism and compromise issues, and I see a lot of designers that don't do that, personal pet peeve, do a precise print and walk away.
For me, it was just as easy to start cutting K&S tube up with the Dremel to fit over the mechanism until I could get that diameter and basic dimension right. Once you get that, it starts coming together more as a parts search than fabrication. The only parts I usually fabricate from scratch are the boiler, running boards (brass, not styrene!), sometimes the cab, and a whole lot of brass wire piping, handrails, and detail. The .010 wire air cooling coil on the D16 was a MAJOR detail part to fabricate, you can't cast or print that, I made a soldering jig in aluminum.
I did styrene running boards on my old Heisler, that was a mistake. That's 'usually' where you pick up a model, and they are the first thing to get damaged and broken. Since then I've always done those in brass by cutting stock and soldering to .020 wire drilled into the boiler shell. You'll never get that entire tube hot enough for a good solder joint. But those take a beating, metal is good.
Oh, and the easy answer on tubing, just buy one of everything for stock. They are made so that each size slides in the next one, so if you're building a tapered boiler just start with the smallest course and layer up the next size. And you may have to cut and compromise to work around your mechanism.
