Specialty Filaments Explained: ESD, Conductive, Magnetic, Smoothable and More

When a Standard Filament Isn't Enough

Most parts are best in a standard material: PLA, PETG, ABS, ASA, nylon or a composite. Specialty filaments exist for the cases where the part needs a property no ordinary plastic has: carrying a small current, shedding static, sticking to a magnet, weighing half as much, or looking like stone. Each one adds that property by mixing something into a familiar base polymer, and that addition almost always costs some strength. The rule of thumb: choose a specialty filament for the one thing it does, and check that its base polymer's other properties are good enough.

Electrical: ESD-Safe vs Conductive

Both are loaded with carbon, but they solve opposite problems, and mixing them up is the most common specialty mistake:

A Note on Ratings

An ESD or resistivity rating is measured by the filament manufacturer on its own test specimens. A printed part has walls, infill and layer bonds that differ from those specimens, so no printed part is ESD-certified by virtue of its material. If a part must qualify for an ESD-controlled area, it has to be tested in its final geometry. The same logic applies to our fire-resistant ABS-FR: the flame rating belongs to the material, not the part.

Magnetic PLA: Attracted, Not Magnetized

Iron-filled PLA contains enough fine iron powder that a magnet sticks to it, which is useful for tool holders, whiteboard parts and teaching demos. It is not itself a magnet. The iron makes parts heavy and cool to the touch, and they can be rusted deliberately with salt water and vinegar for an aged-metal look. Expect lower strength than plain PLA: the filler interrupts the polymer.

Weight: PLA Aero and LW-ASA

Foaming filaments contain an agent that expands as the plastic is extruded, leaving tiny closed bubbles inside the part. The result can weigh around half as much as a solid print of the same shape, which is why RC aircraft builders use them. PLA Aero is the easy, indoor choice. LW-ASA brings ASA's UV and weather resistance, so it's the pick for aircraft and parts that live outdoors. Both are weaker and softer-surfaced than their solid versions: they are for light, not strong.

Finish: PVB, Marble, Sparkle, Silk and Translucent

Several specialties exist purely for how the part looks, and they are the quickest way to a presentation-quality print without painting:

• PVB (Smoothable): its surface dissolves slightly in isopropyl alcohol vapour, melting away layer lines for a glossy, near-molded finish. The best route to a smooth FDM surface on complex shapes.
• Marble PLA: dark speckles in a light base give a stone look that also hides layer lines.
• Sparkle PLA: glitter flakes that catch the light, most striking in dark colours.
• Silk and Matte PLA: a glossy sheen or a flat, layer-hiding finish.
• Translucent PETG: tinted, light-transmitting parts that are still tough enough to be functional, for diffusers and indicator lenses.

Sustainability: Recycled PLA

Recycled PLA is made from reprocessed industrial scrap instead of virgin resin. It prints and performs like standard PLA, so it is a straightforward swap wherever PLA would do. The trade-off is colour: recycled stock is blended rather than pigmented from scratch, so it comes in neutrals.

Supports: Why PVA Exists

PVA is water-soluble. We print it as the support material inside cavities and under overhangs that couldn't otherwise be cleaned out, then dissolve it away. It's the reason internal channels and nested mechanisms can be printed in one piece. You'd normally choose your part's material and let us decide whether soluble supports are needed; mention internal geometry in your notes if you're not sure.

Choosing Quickly

Quote a Specialty Part

Every filament in this guide is selectable on the quote page under FDM, and each shows only the colours it's actually made in. Upload your part, compare specialty and standard options side by side, and add a note if the part has an electrical, weight or finish requirement our engineers should check.