Metal Filled Filament for 3D Printing: Density, Nozzle Wear, and Real Uses

What a metal-filled filament actually is

A metal-filled filament is still a plastic. The base is a regular polymer, PETG in both Prusament data sheets covered here, and the manufacturer disperses a fine metal powder through it. The printed part is not a metal part. It keeps the stiffness, heat tolerance, and limits of PETG, plus whatever the filler brings. If you want a solid metal part, that is a different process entirely, covered in our guide to metal 3D printing.

Not every filler is chosen for the same reason. Some powders are there for looks, giving a surface you can polish or patina. Others, like tungsten and magnetite, are chosen for what they physically do: add mass, stop radiation, or respond to a magnet. This guide focuses on that second group, using the Prusament PETG Tungsten 75% and PETG Magnetite 40% sheets as the reference.

What all of these filaments share is abrasiveness. Metal powder wears a nozzle far faster than plain PETG does, and the high density changes how your slicer estimates material use. Both points come back in every section below, because they shape which printer you can use as much as which settings you pick.

Density: why tungsten changes the math

According to the Prusament sheet, tungsten, also called wolfram, has a density of about 19 grams per cubic centimeter. That is comparable to gold and roughly 1.7 times denser than lead. The filament inherits that trait: at the same weight, a spool of PETG Tungsten 75% holds noticeably fewer meters than a spool of regular PETG. Prusament puts it simply: fewer meters of filament for the same weight.

In practice, the spool looks short, and a finished part feels surprisingly heavy for something that looks like ordinary PETG. That is exactly the point when you want to weight an object: a figure base that stops tipping, a tool handle with better balance, a compact counterweight. Magnetite adds weight too, and Prusament lists plain weighting among the uses for PETG Magnetite 40%.

Density brings one practical catch. Your slicer calculates part weight and cost from the density stored in the filament profile. Use a standard PETG profile and the numbers will be wrong. Prusament notes that the PETG Tungsten 75% profile is not included in PrusaSlicer and provides a downloadable config bundle for the MK3S+. For other printers, the company points you to its support team.

Nozzle wear: why a hardened nozzle is not optional

Both Prusament sheets are blunt about it: tungsten is highly abrasive, and magnetite particles are just as bad. A hardened nozzle is required for both. A soft brass nozzle slowly bores out as the meters go by, which throws off extrusion and line width with no obvious warning. Our guide to 3D printer nozzles walks through the nozzle families and how they hold up to abrasion.

The mechanism is the same as with carbon fiber filaments, with one difference: here the filler is a powder, not fibers. It does not align along the print lines, but it grinds constantly against the nozzle bore and the extruder drive gears. Hardened gears and a filament path without sharp bends make life easier.

Prusament adds a warning specific to tungsten: any printer issue, whether a partial clog or under-extrusion, can significantly reduce the radiation shielding properties of the part. In other words, a worn nozzle does not just make an uglier part. It makes a part that no longer does its job. The company recommends cleaning and calibrating the printer properly and testing it with its calibration object before committing to a functional print.

Print settings: bed, nozzle, and build surface

Both filaments follow the logic of regular PETG, with their own temperatures. For PETG Tungsten 75%, the Prusament sheet lists a nozzle temperature of 260 ± 10 °C and a bed at 80 ± 10 °C, and it calls the heated bed necessary. For PETG Magnetite 40%, the sheet lists 270 ± 5 °C at the nozzle and 100 ± 10 °C on the bed, with no enclosure required.

The build surface follows pure PETG practice: a satin or textured sheet. For tungsten, Prusament recommends cleaning the sheet with isopropyl alcohol, and using the smooth sheet only with a glue stick as a separation layer. For magnetite, the advice flips. Isopropyl alcohol is not recommended because adhesion may become too strong. Instead, the sheet suggests window cleaner on an unscented paper towel, applied to a cold bed, or warm water with a few drops of dish soap.

One caution for magnetite: the sheet reports lower layer-to-layer adhesion than pure PETG. Orient parts so loads do not pull layers apart, and skip it for stressed mechanical parts. For finishing, Prusament notes that both dry and wet sanding work on PETG Magnetite 40%.

Uses: weighting, shielding, and magnetic parts

Tungsten works as shielding because its high atomic number, 74, lets it stop X-rays and gamma rays, as the Prusament sheet explains. The company lists medical applications: shielding for radiopharmaceuticals, test tools for diagnostic radiology equipment, custom gamma camera collimators, and customized shielding covers. The appeal of 3D printing here is producing complex, individualized shapes, since very dense materials are hard to machine.

Let's be clear about what this guide does not claim. It does not validate any protective performance. A real shielding part must be designed, measured, and qualified by a competent professional, with the right thickness and inspection of the printed part. Prusament itself warns that a print defect sharply reduces effectiveness. For a hobbyist, the realistic use case is weighting and experimentation.

Magnetite plays a different game. PETG Magnetite 40% is paramagnetic: anything you print with it can be attached to a magnet, but the part does not become a permanent magnet under home conditions. Prusament lists electronic parts such as switches, potentiometers, and induction loops, electromagnetic shielding, lids for magnetic boxes, tools that stick to a magnetic holder, magnetic puzzles, and art or design pieces.

Is it right for you? Printer and budget check

Before you buy a spool, check three things on your printer. First, the nozzle: if you still run the stock brass nozzle, plan on a hardened nozzle that fits your hotend. Second, the heated bed, which Prusament calls necessary for tungsten and which runs hotter still for magnetite. Third, the extruder, whose drive gears also take abrasion.

You do not need a professional machine. A mid-range printer with a hardened nozzle and a heated bed is enough, and magnetite does not even need an enclosure. The real added cost is the spool itself: tungsten-filled filament is far more expensive than standard PETG, and each spool holds few meters. To see the full picture, our startup budget tool helps you tally printer and consumables.

For a first run, pick something simple and useful: a base that needs weight, a holder that should stick to a magnetic strip. Print Prusament's calibration object first, use the provided profile, and remember that PETG Magnetite 40% does not like loads across layers. These are specialty materials. They solve a specific problem, not everyday printing.

Sources and limits

• Prusament — PETG Tungsten 75%
• Prusament — PETG Magnetite 40%

We organize manufacturer and community documentation; we have not measured these products ourselves. The manual for your exact model takes precedence over general guidance.