Rainbow Color Blend Top

Engineering + Art = Magic primetowerdesigns.com
Beginner's Guide	The Next Dimension	How It's Made

As if straight out of The Wizard of Oz, this twister will have Dorothy singing Somewhere Over The Rainbow in no time! The Big Top circus pattern delightfully transforms into a smooth rainbow effect when spun.

Setting Expectations

This design leans more toward “fun experiment” than pure practicality. On single-nozzle printers it triggers a filament swap at every layer. However, printing several at once keeps the swap count the same, so the time and filament overhead is much more manageable.

Because of all the tiny color pockets, the outer contours won’t be perfectly smooth. This is expected and doesn’t affect performance. You can see this most clearly in the third gallery photo.

For a refined experience that doesn't even require an AMS, check out SpinCraft, the creativity-sparking interactive top kit based on an innovative series of interlocking color disks. That said, Rainbow Twister has its own charm, creating a continuous gradient in a compact form that's easy to pick up and spin.

Filament Colors

Every red/yellow/blue combination I tried worked decently, but it took a lot of experimentation to dial in the colors to avoid a muddy green.

1. Red - Bambu PLA Basic
2. Highlight Yellow - Overture PLA (Bambu PLA Basic yellow works almost as well)
3. Sky Blue - Polymaker PLA Matte (Bambu PLA Basic cyan works almost as well)

For bolder colors you can use an RGB palette, though the yellow/orange section will appear more brown.

Printing

Since most layers of the top have 2 colors, single-nozzle printers will require many filament swaps - 239 of them. While this would be a lot for a single top, the model has a small footprint and many copies can fit onto a plate without increasing the waste, thus reducing the average swaps (and time) per top. The main print profile I uploaded includes 12 tops per plate, though this can be increased even further. With 12 copies, each top requires a mere 20 filament swaps, bringing the cost per top down to about 45 cents.

Tip: Check your purge chute periodically to ensure it remains clear.

Dual-nozzle printers, namely the H2D, really shine here - they only require 2 filament swaps, even when printing a single top. To accomplish this, you'll need 2 red spools (one for each nozzle) and one of the red parts of the top will need to be toggled to use the additional spool. On such a printer, the layer height can also be reduced (0.2mm → 0.1mm) to improve the top's quality without increasing the count of filament swaps. While I don't own an H2D myself, I created an H2D-specific print profile which Bambu was kind enough to test for me.

Assembly

Use a few drops of superglue to attach the halves together. Carefully align the pattern and seams. Don't apply glue too close to the edges or it will ooze out and cause surface discoloration.

You'll typically have 10+ seconds to slide the halves around before the glue starts to set. Use this time to make sure they are well centered, to avoid a choppy spin. One half's surface is ever so slightly larger than the other, so make sure they are positioned such that you can see a tiny rim around the smaller half. Hold firmly in place for ~15 seconds, and then let sit for a few minutes before testing. Wait a few hours before vigorous use.

Thank You

Enter the Next Dimension (Easy to print. Lit by a glow stick. Free.)