3D Printer Filament: A Complete Buying Guide

We've printed thousands of spools across our two-year run with a Bambu P1S. Some materials became favorites. Others taught us expensive lessons. This guide is the cheat sheet we wish we'd had: what each filament is for, what we trust, and what to avoid.

One thing first: the filament you buy matters more than the printer you own. A great printer with bad filament makes bad prints. A modest printer with great filament makes shockingly good ones. Don't cheap out on filament if you care about how the print turns out.

The Four Filaments You'll Actually Use

There are dozens of filament types. For 95% of beginner and intermediate use, you only need to know four:

• PLA — the easy one. What you'll print 80% of the time.
• PETG — for things that need to be tougher (functional parts, outdoor use)
• ABS / ASA — for things that need to be hot-tolerant and impact-resistant (car parts, tool handles)
• TPU — for things that need to bend (phone cases, gaskets, jiggly toys)

Other materials exist (nylon, polycarbonate, PEEK) but they need enclosed, high-temperature printers and aren't beginner-friendly. Master the four above first.

PLA: The Beginner's Best Friend

PLA is the easiest filament to print. It's made from cornstarch, smells slightly sweet, doesn't warp easily, and works on every printer. It's what comes free with most printers, and it's what most "best 3D print" photos online are made of.

When to Use It

• Decorative pieces, figurines, miniatures
• Indoor display objects
• Cosplay props that won't see heat or stress
• Anything where pretty matters more than tough

When NOT to Use It

• Outdoor pieces — PLA degrades in UV light over months
• Anything that goes in a hot car (it warps around 140°F)
• Functional parts under load (gears, mounts, structural pieces)
• Anything food-related (most PLA isn't food-safe even when labeled so)

PLA Variants

The PLA family has gotten interesting:

• Standard PLA — the baseline. Cheap, easy, works.
• PLA+ — PLA with additives for higher impact strength. Slightly stiffer to print but more durable. Our default for prints that will get handled.
• Silk PLA — has a glossy, almost metallic sheen. Looks gorgeous on display pieces. Slightly more brittle than standard.
• Matte PLA — the opposite of silk. Soft, paper-like surface that hides layer lines beautifully. Our pick for any sculpture or organic shape.
• Wood-fill PLA — has actual wood particles mixed in. Sands like wood, smells like sawdust when printed. Beautiful for picture frames and decorative objects.

PETG: When PLA Isn't Tough Enough

PETG (Polyethylene Terephthalate Glycol) is what plastic water bottles are made of. It's tougher than PLA, more heat-resistant (up to ~175°F), and somewhat flexible without snapping. Slightly harder to print — it's "stringier" and needs higher temperatures — but well within beginner reach.

When to Use It

• Phone mounts, car accessories that might sit in the sun
• Functional parts that flex without breaking
• Outdoor items (it's UV-resistant)
• Food-contact items (some PETG is food-safe — check the manufacturer's spec)

The Stringing Problem

PETG loves to leave wispy strings between print sections — it's the material's #1 quirk. Slowing down the retraction speed and lowering the nozzle temperature by 5-10°C usually fixes it. Bambu Studio and OrcaSlicer have PETG presets that handle this automatically.

ABS / ASA: The Tough Stuff

ABS is what LEGO bricks are made of. ASA is a similar material with better UV resistance. Both are stronger than PLA and PETG, hold up to high heat (170-200°F+), and are great for impact-resistant parts. The catch: they need an enclosed printer because they warp dramatically as they cool, and they smell during printing (toxic? probably not at hobby scale, but ventilate anyway).

When to Use It

• Parts that go in cars (especially in summer)
• Tool handles, mounts, brackets
• Anything that might get dropped or stepped on
• Outdoor signage and fixtures (ASA specifically)

When NOT to Use It

• If you have an open-frame printer (skip ABS, just use PETG)
• If you can't ventilate your workspace
• For aesthetic or display pieces — the surface finish isn't as nice as PLA

TPU: When Things Need to Bend

TPU (Thermoplastic Polyurethane) is rubbery. Squishy. Flexible. It comes in different hardness grades (95A is firm, 60A is super-flexible). Great for phone cases, gaskets, watch bands, and any part that needs to compress or bend without breaking.

The Catch

TPU is slower to print than rigid filaments — sometimes half the speed. It needs a direct-drive extruder (not Bowden), which the Bambu printers all have. It also tends to absorb moisture from the air faster than other filaments, which leads to print quality issues if you store it badly.

Storing Filament Properly

Here's the secret most beginners learn the hard way: filament absorbs moisture from the air, and wet filament prints terribly. You'll see popping noises, stringing, blobby layers, and rough surfaces. The fix is keeping filament in airtight, dry storage.

Your Options

• Vacuum bags with desiccant — cheapest option. Buy gallon-size vacuum-seal bags and toss in silica gel packets. Works fine for most filaments.
• Filament dry boxes — sealed plastic boxes with humidity indicators. Better than vacuum bags because you can dispense filament directly while it stays dry.
• Filament dryers — heated boxes that actively dry filament before/during printing. Essential for TPU and nylon, nice-to-have for PETG, optional for PLA.

What Brands We Avoid (And Why)

We're not naming specific bad brands because it's not fair to those companies — quality fluctuates. But here's the pattern: avoid the cheapest filament on Amazon (the $9-12 spools). The diameter tolerances are sloppy enough that the filament jams in the extruder. The color consistency is bad — you'll see streaks within a single spool. And the brittleness varies, so what worked Tuesday breaks on Wednesday.

Stick to $15+ per kilogram. The cost difference per print is pennies. The quality difference is night and day.

Colors and Variety

Once you've nailed quality, have fun. Modern filaments come in:

• Dual-color (gradient) — color shifts from one end of the spool to the other
• Silk multi-color — three or four colors that change every meter or so
• Glow-in-the-dark — actually glows. Great for kids' rooms and Halloween props.
• Glitter / sparkle — has metallic flakes embedded. Looks stunning on flat surfaces.
• Wood, stone, metal-fill — looks and feels like the real material. Heavy and abrasive on nozzles (use a hardened nozzle).

The Workshop's Honest Take

Most people overthink this. Here's our actual buying pattern:

• 80% of our prints: Bambu PLA Basic or PolyTerra Matte PLA. White, black, and one or two seasonal colors.
• 15% of our prints: PETG for functional pieces — usually black or white.
• 5% of our prints: Specialty (TPU for gaskets, ABS for car parts, silk PLA for showpieces).

Pick one PLA brand you trust. Buy black and white in 1kg spools. Add one color when you start a new project. Resist the urge to fill your storage with 30 colors you'll use once. Build your filament library slowly, around projects you're actually printing.

And dry your filament. We can't say it enough. Most "my printer is broken" stories on Reddit are actually "my filament is wet" stories. A $90 dryer pays for itself in saved prints within a month.