How I finally got clean cutaway prints on my Saturn V build - steps that actually worked

I did a cutaway S-IC stage a couple years back at a similar scale and ran into the same warping problem on curved cut edges. My fix was a bit diffrent: I left a thin web of material bridging the opening and sliced it out with a hobby knife after the halves were glued. Kept the shells rigid during printing and the seam came out decent. Crude, but it worked, and I only had one stage to worry about rather than three.

On painting internals before assembly, full agreement from me. I tried touching up a feedline after gluing a stage together once and ended up repainting half the intertank section. Never again.

One thing I'd add from experiance: layer lines from a filament printer show up badly on curved tank walls at this size, and sanding the outside of a cutaway is risky because you can knock the interior detail loose. I ended up printing just the exposed half shells on my resin printer and kept the rest in filament. Cost a bit more but the S-IVB forward dome looks way cleaner now. My build also lives on a heavy base, an oak plaque I picked up at a hobby shop, for the same tipping reason. At 60cm tall the whole thing is basially a lever waiting for a cat or a sleeve to catch it.

That common plug idea across all three stages is clever, wish I'd thought of that on mine. I ran a wooden dowel up through the core instead, so the stages stack on the dowel and I can still pull one off to show the interior. Downside is you can't twist the stages for display angles, they're locked facing one way.

How'd you handle the engine bell cluster at that scale? At 1:185 the F-1 nozzles are tiny and mine came out fragile enough that two snapped off during painting.

Not sold on the resin half shells honestly. Anything the size of a stage section on a resin printer comes out brittle, and you're also dealing with curing resin in a big open vat and washing a part that tall without it wobbling. I snapped a tank wall on mine just snipping supports off, so a whole exposed dome would've shattered for sure. Filament with a fine nozzle plus a coat of filler primer smoothed the banding on mine well enough that nobody notices at display distance. Cheaper too, and a dropped model at that height is a real risk.