Hardened vs brass nozzles: when you actually need one

Brass is the default nozzle material because it conducts heat superbly and machines cleanly, which makes it cheap and good at the actual job. Its weakness is hardness: brass is soft, and anything abrasive in the filament will wear the orifice open.

What counts as abrasive

More filaments than people expect:

• Carbon fibre (PLA-CF, PETG-CF, nylon-CF) — the worst offender in common use.
• Glass fibre filled composites.
• Glow-in-the-dark — the phosphorescent particles are genuinely abrasive, which surprises people.
• Glitter and sparkle filaments.
• Wood, metal and stone fill — variable, but assume abrasive.

Plain PLA, PETG, ABS, ASA and TPU are not abrasive. A brass nozzle printing those will last a very long time.

How fast does brass actually wear?

Faster than most people believe. Continuous printing with a carbon-fibre filament can visibly open up a brass nozzle within a few spools — sometimes within one. The failure is gradual and sneaky: the hole widens, extrusion width drifts, walls thicken, dimensional accuracy slips, and you spend an evening recalibrating a printer that is mechanically fine. If your prints have quietly got worse and you have been printing something filled, check the nozzle first.

The options above brass

• Hardened steel. The usual answer. Cheap, widely available, survives abrasives well. The trade-off is thermal conductivity — steel conducts heat considerably worse than brass, so you may need to print 5–10 °C hotter to get the same flow.
• Ruby and diamond tipped. Excellent wear resistance with brass-like heat transfer, at many times the price. Justified if you print abrasives constantly.
• Plated copper / brass with a wear coating. A reasonable middle ground where available.

The honest recommendation

Keep a brass nozzle in the printer for everyday PLA and PETG, and keep one hardened steel nozzle in the drawer to swap in when you print anything filled. That is a couple of pounds of insurance against a slow, hard-to-diagnose decline in print quality.

If you print carbon-fibre filament routinely, just fit hardened steel and leave it there. The slight temperature bump is a smaller nuisance than replacing brass nozzles on a schedule you keep forgetting.

Do not forget the rest of the path

Abrasive filament wears everything it touches, not just the nozzle. Extruder gears and — on Bowden setups — the PTFE liner also take a beating. If you have been printing composites for a while and something feels off, the nozzle is the first suspect but not the only one. See PTFE tubing and when to replace it.

Questions people ask

Do I need a hardened steel nozzle?

You need a hardened steel nozzle only if you print abrasive filaments: carbon fibre, glass fibre, glow in the dark, glitter, wood, metal or stone filled. Plain PLA, PETG, ABS, ASA and TPU are not abrasive, and a standard brass nozzle printing those lasts a very long time.

Which 3D printer filaments are abrasive?

Abrasive filaments include carbon fibre and glass fibre composites such as PLA-CF, PETG-CF and nylon-CF, glow in the dark, glitter and sparkle filaments, and wood, metal and stone filled filaments. Carbon fibre is the worst offender in common use. Plain PLA, PETG, ABS, ASA and TPU are not abrasive.

How long does a brass nozzle last?

A brass nozzle lasts a very long time with plain PLA, PETG, ABS, ASA or TPU. With abrasive filament it wears quickly: continuous printing with carbon fibre can visibly widen a brass nozzle within a few spools, sometimes within one. The wear is gradual, so print quality declines slowly rather than failing suddenly.

How can I tell if my nozzle is worn out?

A worn nozzle has a widened hole, which shows up as walls that print thicker than intended, drifting extrusion width and parts that are no longer dimensionally accurate. If print quality has quietly declined and you have been printing a filled or abrasive filament, check the nozzle before recalibrating anything else.

Do I need to change my settings for a hardened steel nozzle?

Yes, usually. Hardened steel conducts heat considerably worse than brass, so you may need to print about 5 to 10 degrees Celsius hotter to get the same flow. Everything else stays the same, provided the nozzle diameter matches the one set in your slicer.

Is a ruby or diamond nozzle worth the money?

A ruby or diamond tipped nozzle is worth it only if you print abrasive filament constantly. They combine excellent wear resistance with heat transfer close to brass, but cost many times more than hardened steel. For occasional abrasive printing, an inexpensive hardened steel nozzle is the sensible choice.

Does carbon fibre filament damage anything besides the nozzle?

Yes. Abrasive filament wears every part it touches, including the extruder gears and, on Bowden printers, the PTFE liner. The nozzle wears first and is the first thing to check, but after long use with composites the gears and tubing may also need replacing.