Rapid 3DShield Boron Carbide Filament

Print thermal-neutron shielding on the FFF printer you already have. Rapid 3DShield Boron Carbide is 50–60% boron carbide in a PLA-based binder. Parts absorb neutrons straight off the print bed, with no debinding, sintering or machining.

Specifications

• Boron carbide content: 50.0%–60.0%
• Filament density: 1.30–1.50 g/cc
• Diameters: 1.75 mm and 2.85 mm
• Formats: 0.25 kg and 0.5 kg spools; 1 kg pellet jars
• Made in South Central Wisconsin, USA

Why it works
Boron-10, 19.9% of natural boron, absorbs thermal neutrons with a cross-section of about 3,840 barns. At mid-spec loading, the calculated thermal-neutron mean free path in a fully dense print is about 0.4 mm, so a few millimetres of wall absorbs nearly all of a thermal beam. Capture products are stable, so the part does not build up long-lived activation. Read the full guide and thickness chart →

Printing

• 0.6 mm hardened steel, standard-flow nozzle (boron carbide is extremely abrasive)
• Prints similar to PLA, with minimal to no warping
• Make sure the filament feeds straight into the extruder
• Use 100% infill for shielding parts
• Do not dry this filament. It is less hygroscopic than PLA, and drying degrades the binder.

👉 Trusted Printers list · Printing guide

Used as printed, not sintered
Boron carbide sinters at about 1,956 °C (3,553 °F), beyond most furnaces. Neutron absorption comes from the boron content, so parts are used in their green state.

Applications

• Neutron detector shielding, liners, masks and collimators
• Beamline, sample-environment and neutron-imaging fixtures
• Prototyping before committing to hot-pressed B₄C
• One-off and short-run parts with no tooling or machining

Mixed neutron and gamma fields? Pair it with Rapid 3DShield Tungsten. Put boron carbide on the neutron side and tungsten behind it, where it also absorbs the 0.48 MeV capture gamma.

Purchase orders and volume
Most boron carbide ships on purchase orders to labs and OEMs, often dozens of spools at a time. Email info@thevirtualfoundry.com for a quote, large-order lead times, or pellet volumes. Need a different loading or powder? See Custom Filamet™ compounding.

Documents
👉 SDS and TDS · Research papers · rapid3dshield.com

FAQ

❓ Can I print this on my printer?
✅ Almost certainly. It works on nearly all open-architecture FFF/FDM printers with a 0.6 mm hardened steel nozzle.

❓ Can I sinter it?
✅ No. It is designed to be used as printed.

❓ Does it block gamma rays or X-rays?
✅ Not well. Boron and carbon are light elements. Use Rapid 3DShield Tungsten for photons.

❓ How strong are printed parts?
✅ Sturdy enough to handle and install, but they won't carry load as well as the base PLA would. Mount load-bearing parts in a holder.

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