We Broke Them to Find Out
Every 3D printer owner has had this moment.
You’re standing in front of your filament shelf.
Red Bull or coffee in hand.
Staring at rainbow, dual-color, and tri-color spools thinking:
“Yeah… but which one of these is actually strong?”
Because let’s be honest:
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Rainbow filament looks awesome
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Dual color looks sick
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Tri-color looks like your printer is showing off
…but none of that matters if your part snaps the first time you look at it wrong.
So today, we decided to stop guessing and actually test it.
The Big Question
Is solid-color filament stronger than multi-color filament?
To find out, we tested four versions of the same exact filament:
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Single color
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Dual color
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Tri-color
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Rainbow
Same material.
Same printer.
Same settings.
Same test.
The only variable? Color.
Test Setup (Keeping It Fair)
All test samples were printed using identical parameters:
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Printer: Bambu Lab X1C
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Walls: 3
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Infill: 15% rectilinear
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Material: Silk PLA
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Model: Custom bridge designed for force testing
Each bridge fits directly into our force gauge, allowing us to measure exactly how much force it takes to cause failure — recorded in Newtons.
This isn’t a bend-it-by-hand test.
This is controlled, repeatable, and measurable.
Why Multi-Color Might Be Weaker (The Theory)
Here’s the theory — or at least what makes sense in a maker brain.
Multi-color filament typically involves:
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Multiple pigments
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More complex extrusion paths
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Potential changes in melt flow
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Tiny inconsistencies where colors transition
In theory, that extra complexity could affect layer bonding.
So logically, you’d expect this strength order:
Single color → Dual color → Tri-color → Rainbow
But thinking and knowing are two very different things.
So we broke some filament.
The Results
🌈 Rainbow Filament (Apple Rainbow)
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Failure Force: 23.5 Newtons
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Equivalent: ~5.2 lb of force
Instead of snapping cleanly, the sample bent first and then slowly cracked apart. No dramatic snap — just a gradual failure.
That’s about the same force as holding a five-pound weight or half a gallon of milk.
🎨 Dual-Color & Tri-Color Filament
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Failure Force: ~26 Newtons
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Difference between them: ~0.01 lb of force
Both dual-color and tri-color samples landed in nearly the exact same range. The difference between them was so small it’s essentially a rounding error.
In other words:
They’re functionally the same in strength.
⚪ Single-Color Filament
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Failure Force: 29.8 Newtons
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Equivalent: ~6.7 lb of force
This sample took the most force before cracking and showed more resistance before failure.
That’s roughly the same as holding a seven-pound weight, or a half-gallon plus a quarter-gallon of milk.
What This Actually Means
Yes — solid-color filament was the strongest in this test.
And yes — rainbow filament was the weakest.
But here’s the important part:
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Dual-color and tri-color filament performed very close to solid color
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The biggest strength drop happens with rainbow filament, not multi-color in general
So this isn’t “multi-color is weak.”
It’s more accurate to say:
The more complex the color transition, the more strength you may give up.
Back to the Filament Shelf
Rainbow filament still looks awesome.
Dual color still looks slick.
Tri-color still looks like you printed it just to flex.
But now you know what you’re trading for those looks.
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If strength matters: solid-color silk PLA wins
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If appearance matters: you already knew the answer
Because sometimes the goal isn’t “strong.”
Sometimes the goal is:
“That looks awesome.”
Want More Tests?
Huge thanks to Amolen for supplying the filament and being cool with honest testing — no scripts, no filtering, no “please make it look good.”
All tested filaments are linked below.
And remember:
Color is what you notice first — strength is what you notice when it fails.