I didn't purge enough material on some of the colors (white/black to red), but overall I'm happy with the outcome.
Red - Protopasta Opaque Red
Blue - Atomic filament royal blue
White - Atomic filament bright white
Black - Atomic filament jet black
what's the MMU setup?
It's been a while since I set it up, but I think this was all of the changes. I did these mods while I was setting up and it was never fiddly for me like it is for a lot of folks.
PTFE clip: http://www.thingiverse.com/thing:3587022
Opened up selector: https://www.printables.com/model/103029-mmu2s-selector-with-mods-remixed-to-refine-filamen
RMU inspired buffer: https://www.printables.com/model/77054-mmu2s-buffer-inspired-by-rmu-buffer
PTFE coupler: https://www.printables.com/model/6605-prusa-mmu2-ptfe-holder-m10-passthrough-adapter
Larger PTFE tubing (3mm ID)
Looks pretty great despite the flushing problem. I think I like the red color where "too much" white is behind it. Wonder if you could set the whole model to be white Infill or at least some white directly behind the red...
What's your setup? Bambu with AMS?
The part that you're referring to is a little closer to the color as stands by itself. I also had wipe to infill turned on and I'm not entirely convinced that the "opaque red" is really 100% opaque.
I had to search for a while to find a good red that I liked. I really want to try Dragon Red by Materio3D (link) but they've been out of stock for a while, even on Voxel Factory's website so I think they've stopped making it.
I printed on a MK3S+ with MMU2s. The modifications I mentioned in my other comment have made it rock solid, a couple thousand color changes on this print without issue.
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