Silicon Carbide Abrasive Nylon Filament: Grit, Uses, Specs
Material guide · 7 min read · updated 2026-10-24
Silicon carbide abrasive nylon is nylon monofilament with SiC grit mixed through it before extrusion. As the filament flexes against a part, grit on the tip and sides cuts, and as the nylon wears, fresh grit is exposed. It is the most common abrasive filament for deburring, edge radiusing, surface finishing and floor stripping.
This page covers how the material is built, which numbers matter (diameter, grit and loading), and typical starting specifications for common jobs.
How SiC abrasive filament is made
Grit is blended into molten nylon and extruded as monofilament, so the abrasive is spread through the whole cross-section rather than glued to the surface. Filament producers typically load 20–40 % grit by weight. The base polymer is commonly nylon 612, chosen because it keeps its stiffness when wet better than PA6 or PA66 (see PA612).
SiC is very hard and sharp but relatively brittle. On a hardness comparison published by one filament producer, silicon carbide is about 2,480 Knoop, against about 2,100 for aluminium oxide and 7,000 for diamond. The same producer notes that the SiC it uses contains less than 0.1 % iron oxide and no free iron, so it can be used on aluminium parts without iron-contamination corrosion.
Diameter, grit and loading
Coarser grit needs a thicker filament to carry it. The pairings below are typical of commercial abrasive filament ranges.
- Brush stiffness rises with roughly the square of filament diameter in a packed tuft, so a small diameter change has a large effect on aggressiveness.
- Finer grit in the same filament means more cutting points. Producer data puts 120 grit at about 50 % more particles on the surface than 80 grit.
- Raising loading from 30 % to 40 % adds about one-third more grit. Going above 40 % noticeably reduces filament durability.
| Filament diameter | Typical grit | Typical loading |
|---|---|---|
| 0.30 mm | 600 | 20 % |
| 0.46 mm | 500 | 30 % |
| 0.56 mm | 120, 240, 320 | 30 % |
| 0.76 mm | 240 | 30 % |
| 0.89 mm | 180 | 30 % |
| 1.02 mm | 80, 120 | 30–40 % |
| 1.27 mm | 80, 120 | 30–40 % |
| 1.52 mm | 46 | 30 % |
| 1.78 mm | 36 | 25 % |
Typical applications and starting specs
These are starting points, not rules. Trim length, fill density, speed and coolant all change the result. Our abrasive nylon brushes cover disc, wheel, roller, end and tube formats.
| Application | Diameter | Grit |
|---|---|---|
| Floor stripping | about 1.5 mm | 46 |
| Aggressive floor scrubbing | about 1.0–1.3 mm | 80–120 |
| Floor cleaning / buffing | 0.4–0.5 mm | 320–500 |
| Sheet and coil cleaning | 0.89–1.02 mm | 80–180 |
| Parts deburring | 0.56–1.02 mm | 120–240 |
| Wood structuring | 1.14–1.52 mm | 46–80 |
| Wood denibbing / finishing | 0.56–1.02 mm | 120–240 |
Brush wear and set-up
Short-trim and long-trim abrasive brushes wear in different ways, and both affect how you run them. Short-trim brushes wear from the tips. As the filament gets shorter it gets stiffer, so the brush becomes more aggressive over its life. The usual starting deflection of about 3 mm (1/8 in) cannot be held without more pressure, and that extra stress at the flex point can eventually snap filaments.
Long-trim brushes, including long-string deburring tools that use the sides of the filament, wear differently. The filament gradually tapers as nylon and grit wear away, stiffness drops, and the tips start breaking off. In continuous production these tools are usually changed on a schedule to keep the finish consistent.
Most premature failures come from fatigue at the base. Filament producer guidance points to two causes: parts positioned too close to the brush core, which over-flexes the filament, and heat at the flex point, which circulating coolant reduces.
Pros and cons
- Pro: the flexible filament follows contours and cutouts, so it deburrs without changing part geometry the way a rigid wheel can.
- Pro: no wire breakage. For many finishing jobs it is a safer alternative to wire. See abrasive nylon vs wire.
- Pro: low iron content makes it suitable for aluminium and other non-ferrous parts.
- Con: heat is the enemy. Nylon softens as temperature rises, and one producer reports that stiffness drops by about another 50 % between room temperature and 60 °C. Dry, fast running can melt filament tips, so use coolant or lower speed where possible.
- Con: in general abrasive practice SiC is preferred for non-ferrous metals, stone and glass, while aluminium oxide is preferred for high-tensile ferrous work. Test on steel before committing.
How to specify and alternatives
Specify grit type (SiC), grit size, filament diameter, base nylon if it matters (PA612 or PA6), crimped or straight, trim length, brush format and mounting (shank, arbor bore, thread), and maximum operating speed. Our RPM and surface speed guide explains why speed ratings matter. Send a part drawing and the burr or finish target with your RFQ so the factory can propose grit and diameter.
Alternatives: aluminium oxide filament for tougher grit on steel and finer finishes, and ceramic grain filament for the fastest cut on hard alloys.
Frequently asked questions
- What grit abrasive nylon brush should I use for deburring?
- For general parts deburring, 120–240 grit on 0.56–1.02 mm filament is a common starting point. Use coarser grit (80) for heavy burrs and finer grit (320 and above) for light edge breaking and finishing.
- Is silicon carbide or aluminium oxide better for abrasive brushes?
- SiC is harder and sharper and is the most widely used abrasive filament. It is usually preferred on aluminium, brass, titanium, stone and glass. Aluminium oxide is tougher and is often preferred on steel and for finer finishes.
- How much grit is in abrasive nylon filament?
- Typically 20–40 % by weight, with 30 % the long-time standard. Loadings above 40 % reduce filament durability.
- Can abrasive nylon brushes be used wet?
- Yes. Coolant or water reduces heat, which is the main cause of filament softening. Filament on a PA612 base keeps its stiffness better when wet.
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