Spray Gun Cleaning Brush

A spray gun cleaning brush is a hand tool for clearing dried coating residue from the internal passages of paint spray guns, airbrushes, and similar precision fluid-handling equipment. It is not a broad-bristle brush for wiping down the outside of the gun. It is a bore-cleaning tool built around a twisted wire stem with short bristles held between the two twisted wires. The working end forms a brush diameter matched to a specific passage inside the gun.

Typical construction starts with a steel wire loop. Bristle material—brass wire, nylon PA, or less commonly natural bristle—is laid across the loop, and the wire is twisted to lock the filaments in place. The result is a cylindrical brush with a plain stem, straight wire, or loop handle on the opposite end. The brush is inserted into the fluid nozzle, air cap passage, or cup connection, rotated by hand, and withdrawn along with loosened residue. Solvent or gun cleaner is used as the carrier during the operation.

This tool fits into the disassembly-and-clean step of the spray gun maintenance sequence. Most technicians remove the air cap, fluid nozzle, needle, and cup before brushing. Brushing removes the attached deposit that solvent alone will not lift, particularly dried paint at the nozzle throat, threads, and sealing faces. It does not replace solvent soaking, ultrasonic cleaning, or calibration after reassembly.

The brush is selected by the bore diameter, not by the gun model alone. Two guns from different manufacturers may have nozzles with different internal diameters, so the set approach is common: several brush sizes cover the majority of passages. For OEM or production environments, brushes can be matched exactly to the gun’s fluid and air passage dimensions.

The following table lists the common production range for spray gun cleaning brushes. Dimensions and materials can be adjusted to your specific passage dimensions.

The brush diameter is the most critical specification. It must pass through the narrowest access opening while still contacting the passage wall. If your gun has unusual bore dimensions, we can produce brushes in custom diameters and working lengths.

Spray gun cleaning brushes are most valuable where dried paint and coating residue collect in small, hard-to-reach internal areas that solvent alone cannot clear. Typical use environments include:

• Automotive collision repair shops — cleaning HVLP and conventional spray guns between basecoat and clearcoat jobs, especially nozzle orifices and air cap holes.
• Industrial finishing lines — maintaining air spray and air-assisted airless guns used with primers, enamels, and two-component coatings.
• Woodworking and furniture finishing — clearing lacquer, varnish, and stain build-up from spray equipment used in cabinet and millwork shops.
• Airbrush and model painting — cleaning fine nozzles and needle passages where brush diameters under 2 mm are required.
• Paint manufacturing and testing labs — maintaining small spray and sample equipment between formula changes.
• General precision cleaning — any small threaded bore, orifice, or fluid passage where a small wire brush set is useful, including fuel passages, lubrication points, and air tool maintenance.

Start with the smallest bore you need to reach

Measure the internal diameter of the nozzle, air cap hole, or fluid passage. The brush diameter should be slightly smaller than the bore—typically 0.1–0.3 mm clearance—so it enters without binding but still contacts the wall. A brush that is too large will jam or bend; one that is too small will spin without scrubbing.

Choose bristle material by deposit and surface

• Brass wire — best for dried paint, cured coatings, and heavy build-up on hardened steel or stainless components. Brass is non-sparking and less aggressive than steel wire.
• Nylon PA — best for aluminum parts, anodized surfaces, plated components, and fine orifices where any metal contact is a risk. Nylon works well with solvent-softened residue.
• Natural bristle — for very fine passages or delicate surfaces where even nylon is too stiff; lower scrubbing force but compatible with most solvents.

Confirm the working length reaches the build-up

Measure from the cleaning access point to the deepest residue location. The bristle section must extend past the deposit, and the overall length must allow comfortable hand control. A stem that is too long flexes and reduces control; a stem that is too short leaves residue in the bottom of the passage.

Buy a set when passages vary in size

Single brushes work when every gun in the shop is the same model. When several gun brands or nozzle sizes are in use, a set with graduated diameters and both brass and nylon options is more practical. A set also covers future gun purchases without a second order.

When a brush is not enough

If the nozzle is completely plugged with catalyzed or baked-on coating, a brush may not clear it. First soak the parts in the recommended gun cleaner or use an ultrasonic cleaner. If the passage remains blocked, the nozzle may need replacement. Brushing is for routine residue removal, not for salvaging severely damaged parts. For aluminum or brass internal surfaces, always use nylon or natural bristle; brass wire is reserved for steel or stainless passages.

Spray gun cleaning brushes are rarely off-the-shelf for every OEM specification. We build to your nozzle and passage dimensions. The following attributes can be adjusted for your application:

• Brush diameter — custom sizes from 0.5 mm to 12 mm, in 0.1 mm increments when required.
• Working length and overall length — matched to passage depth and handle clearance.
• Fill material — brass wire, nylon PA (6.6 or 6.12), natural bristle; filament diameter chosen for stiffness and wear.
• Stem material — carbon steel with zinc or nickel plating, 304 stainless steel, or brass for non-magnetic environments.
• Handle — twisted loop, straight wire, plastic-dipped handle, or plain stem for insertion into a holder.
• Set composition — number of brushes, sizes, and material mix chosen for a specific gun platform.
• Color coding — different handle dip colors to identify brush diameter at a glance.
• Packaging — bulk, individual bags, retail cards, or workshop sets.

To define the custom configuration, provide the bore ID, passage length, access opening, component material, residue type, solvent, and any handle preference. A drawing or sample gun part speeds up the process. If your project requires material compliance documentation, inspection reports, or third-party testing, we can support those requirements as part of the customization process.