Spray Gun Nozzles: Tip, Pattern and Pressure for Coating, Cleaning and Dosing

A spray gun nozzle is the business end of every manual coating, cleaning and dosing job: paint, sealant, degreaser, sanitiser, pesticide. Pull the trigger and liquid becomes a fan or a cone. The tip decides the shape, the pressure decides the finish, the orifice decides the flow. Get any one wrong and you are either stripping the coat off or flooding the floor.

The Selection Framework: Four Numbers

Every spray gun duty reduces to four numbers. Write them down before you touch a catalogue:

1. Pattern (fan angle): how wide the spray opens. 10° for a pencil line, 110° for a wide flood.
2. Orifice (flow): litres per minute at pressure. The “size” of the tip.
3. Atomisation (air cap): how the air shears the fluid. External for thin, internal for thick.
4. Transfer requirement: does the material need to land on the part (transfer efficiency) or cover fast? HVLP vs airless is this trade.

A tip chosen without these four is a guess with a part number. With them, the selection is arithmetic.

Reference Table: Tip by Duty

Tip	Angle	Orifice	Pressure	Use
11002–11004	110°	0.02–0.04“	Airless	Wide flood, primer
517	50°	0.017“	Airless	General coat
615	60°	0.015“	Airless	Fine finish
210	20°	0.010“	Airless	Stripes, edges
HVLP 1.3 mm	40°	1.3 mm	Air-assisted	Fine finish, low overspray
HVLP 1.8 mm	60°	1.8 mm	Air-assisted	General, thicker fluids

Tip codes follow the universal system: angle + orifice. The table is a starting point; test panels at your fluid settle it.

The Three Things a Gun Nozzle Controls

Every spray gun nozzle is specified by three numbers, and they are the only numbers that matter:

• Tip pattern (angle): how wide the fan opens, 10° for a pencil line, 110° for a wide flood.
• Orifice (flow): how much liquid per minute at a given pressure, the “size” of the tip.
• Air cap / atomisation: how the air shears the liquid, external mix for thin fluids, internal mix for thicker.

A “517” tip means 50° fan, 17 on the orifice scale (roughly 0.017“ → a specific L/min at pressure). That coding is universal across gun brands; learn it once and every gun speaks the same language.

Pattern Width: How Far, How Wide

The fan angle sets the strip you paint in one pass. A narrow 10–25° tip lays a line for stripes and edges; a 40–65° tip is the general-purpose coat; an 80–110° tip floods a wide, flat surface fast but with less impact.

Standoff matters as much as the angle. The rated pattern width is measured at a fixed distance (usually 30 cm). Closer and the fan is narrower and heavier; farther and it widens and thins. The rule: hold the distance the tip was rated for. Inconsistent standoff is the #1 cause of uneven coats, not the tip, the wrist.

Pressure and Finish

Pressure controls atomisation, not just flow. Too low and the fluid leaves as blobs (orange peel, spatters); too high and you make overspray that never lands (wasted material, breathing hazard, floor cleanup). The window is narrow and fluid-dependent:

• Thin coatings (paint, sanitiser): lower pressure, finer atomisation.
• Viscous (sealant, adhesive): higher pressure, larger orifice, or you starve the tip.
• Airless vs HVLP: airless drives fluid at high pressure through a small orifice (reach, speed); HVLP uses high volume low pressure (less overspray, more transfer efficiency). Pick by whether you care more about speed or material saved.

Air Atomising Gun Nozzles

When the finish has to be uniform and the fluid is tricky, coatings, pharmaceuticals, food glide, you use an air atomising gun nozzle. Compressed air shears the liquid into 10–60 µm drops at any flow, giving a controlled fan or cone that airless cannot match on delicate work. The cost is the air supply and the cleaning. For most industrial washdown and dosing, hydraulic (pressure-only) gun nozzles are simpler and enough.

Matching Tip to Duty

Duty	Tip	Pressure	Why
Fine finishing coat	40–65° airless, mid orifice	Rated for fluid	Even fan, controlled atomisation
Striping / edges	10–25°	Lower	Narrow line, no bleed
Wide flat flood (degrease)	80–110°	Higher	Coverage speed
Sanitiser / dosing	Air atomising or wide fan	Lower	Even wet, low overspray
Thick adhesive	Large orifice, airless	Higher	No starve

The table is a starting point. The real check is a test panel at your actual fluid and pressure. For the airless tip numbers behind each row, the paint sprayer tip size chart decodes the three-digit code and lists the rated flow at 2,000 psi.

Overspray, Transfer and the Floor

Overspray is material that leaves the tip and never reaches the work. It is wasted money and a cleanup and exposure problem. Three controls:

• Transfer efficiency: HVLP and air-assisted airless beat straight airless on keeping material on the part.
• Pattern match: a fan wider than the part wastes edges; narrower means overlap passes and stripes.
• Distance: hold the rated standoff so the fan is at its rated width when it meets the surface.

If you are mopping the floor under a spray gun, the tip is wrong, the pressure is wrong, or the wrist is moving. Fix all three.

Material and Chemical Service

Gun nozzles see aggressive fluids, solvents, acids, sanitisers. Material choice:

• Stainless (303/316L) for water-based and mild chemistry.
• PP / PVDF for acids and oxidisers; PVDF for heat.
• PTFE-lined for the broadest resistance.
• Ceramic or carbide orifice in abrasive duty (filled coatings, slurries). The orifice wears, not the body.

For solvent-borne coatings, stainless or PTFE-lined tips survive; for water-based sanitiser, stainless is fine.

Industry Applications: Where Gun Nozzles Earn Their Keep

• Industrial coating: airless for speed, HVLP for transfer; the tip sets the finish.
• Maintenance painting: a 517 airless tip, mid orifice, most jobs.
• Food-safe sanitiser application: a wide flat fan at low pressure; even wet, no overspray on the product.
• Chemical dosing from a gun: an air atomising gun for uniform drop control on a moving part.
• Anti-corrosion coating: thick, filled products; a large-orifice airless tip, or an air-assist for the finish.
• Touch-up and repair: a small HVLP tip, fine finish, minimal overspray.

Each application is the same four numbers with a different answer set.

A Worked Example

You are sanitising a food line with a handheld gun, water-based sanitiser, wanting even wet with low overspray.

1. Fluid: water-based, low viscosity → hydraulic wide fan, no need for air atomising.
2. Pattern: line surfaces, some flat → 65–80° tip.
3. Pressure: lower end of rated (less overspray, sanitiser transfer matters).
4. Material: 316L stainless. Sanitiser is mildly corrosive but water-based.
5. Distance: hold 30 cm, the rated fan width.

Even coat, minimal waste, no floor lake.

Troubleshooting: Why the Floor Is Wet

Overspray on the floor is never “the tip is bad.” It is one of:

1. Pressure too high → fine atomisation but the fan blows past the part. Drop pressure to rated for the fluid.
2. Tip too wide for the part → edges miss, land on the floor. Narrow the angle or move closer.
3. Standoff inconsistent → fan width varies pass to pass, stripes and puddles. Lock the distance.
4. Wrong gun type → airless where HVLP fits (or vice versa). Match transfer efficiency to the job.

The fix is always tip angle (pattern), pressure (finish), standoff (width), in that order.

How We Compare to the Catalogue Brands

The big finishing catalogues (Spraying Systems, Graco, Wagner) publish gun tips with documented fan angle, orifice flow and atomisation. Our gun nozzles track the same coding. A 517 tip is a 50° fan at a fixed orifice flow everywhere. What a buyer should weigh is spare-tip stock, compatibility with your gun, and lead time, not the angle math, which is universal. We publish per-tip flow and pattern so you size against the same numbers and keep tips on the shelf.

FAQ: Spray Gun Nozzle Questions We Actually Get

Q: What does “517” mean on a tip? A: 50° fan, 17 on the orifice scale (about 0.017“, a specific flow at pressure). The code is universal; learn it once, read every tip.

Q: Airless or HVLP for my job? A: Airless for speed and heavy films (industrial, big surfaces); HVLP for transfer efficiency and fine finish (where the material is expensive or the overspray is a hazard). The material cost usually decides.

Q: Why does my coat run (sags)? A: Too much material: the tip flows too much at your speed, or the standoff is too close. Narrow the fan, move back, or lighten the passes.

Q: Why does my finish look orange-peel? A: The drops are too coarse: pressure too low for the fluid, or the wrong tip for the viscosity. Raise pressure (within the tip’s rating) or switch to a finer atomising tip.

Q: Can I clean a tip with a wire? A: Never. A wire enlarges the orifice and ruins the pattern. Use the cleaning brush that came with the gun, or soak in solvent.

Maintenance: What Kills a Gun Tip

• Orifice wear: abrasive or filled coatings enlarge the orifice; the fan widens, the finish thins. Ceramic or carbide tips for abrasive material.
• Clogging: dried material in the tip; the pattern distorts. Clean after every use; soak for heavy jobs.
• Tip seat damage: a damaged seat leaks and spits. Replace the seat, not just the tip.
• Cross-threading: the small threads damage easily. Use the right wrench, seat snug.

A gun tip is a consumable. Clean it after every use and replace on inspection. A worn tip costs more in material than it does to replace.

Selection Checklist (Print This)

• Pattern chosen for the part, narrow for lines, wide for floods
• Orifice sized for the fluid and the film you need
• Atomisation matched, external thin / internal thick
• Transfer decision made, HVLP vs airless vs air-assist
• Standoff locked at the tip’s rated distance
• Spare tips on the shelf. They wear and clog

The Physics: Pattern, Film and the Finish

Three physical facts drive every gun tip:

• The fan width scales with the tangent of half the angle. A 40° tip at 30 cm makes a ~22 cm band; at 60 cm it is 44 cm. The angle rating is at a fixed distance: hold the standoff.
• The film thickness is flow ÷ (fan width × speed). The same tip at twice the speed lays half the film. The tip size and your pass speed are one equation, not two choices.
• The droplet decides the finish. Coarse drops (low pressure, big orifice) sag or orange-peel; fine drops (high pressure, small orifice, or air assist) level into a smooth film. The finish is a droplet story.

Every “my paint is bad” complaint is one of these three numbers out of line, pattern, film, or droplet.

Transfer Efficiency: The Material Math

Transfer efficiency is the share of the material that lands on the part:

• Airless: ~50–60%. Fast, heavy film, more overspray.
• Air-assisted airless: ~65–75%. The compromise; fine atomisation with good transfer.
• HVLP: ~65–80%. The best transfer; the material saved pays for the slower application.
• Conventional air: ~40–50%. The old standard; now mostly for fine finish where overspray is acceptable.

The trade is speed vs material saved. For expensive coatings, HVLP’s extra 20% transfer is real money; for cheap primer, airless speed wins.

The Five Mistakes to Avoid

1. A wire in the tip: the orifice is ruined; the stripe is yours. Brush or soak, never poke.
2. Wrong pressure for the fluid: too low orange-peels, too high oversprays. Use the tip’s rating and the fluid’s viscosity.
3. Skipping the test panel: the tip looks right and sprays wrong on your fluid. Test first; the panel is the spec.
4. Standoff drift: the wrist moves, the fan changes width, the coat stripes. Lock the distance.
5. One tip for everything: a fine-finish tip on primer floods it; a big tip on a touch-up drips. Change tips for the job.

Every one is a process error. Answer the four numbers and the five mistakes disappear.

Working the Gun: Stroke, Distance, Overlap

The tip is half the finish; the technique is the other half:

• Keep the gun perpendicular: angling the gun changes the pattern and the film; 90° to the surface, always.
• Flex the wrist, not the arm: a parallel pass at a consistent distance is the whole trick; swing from the wrist, keep the elbow locked.
• Overlap 50%: each pass overlaps the last by half its band; that is how a coat stays even. Less and you stripe; more and you double the film.
• Trigger at the edges: start and stop the pass off the part; triggering on the edge leaves a heavy start line.

The same tip, two operators, two results. Technique is the last 50% of the finish.

Material Selection for Gun Tips

Material	Best for
Brass	Most solvent-borne coatings; cheap, standard
Stainless	Aggressive chemistry, water-based corrosives
Tungsten carbide	Abrasive, filled coatings; the orifice outlasts brass many times
Ceramic	Heavy abrasive duty; the hardest, most brittle

The tip is the wear part: in filled or abrasive coatings, a tungsten carbide tip pays for itself in a season.

What to Send a Supplier for a Quote

1. Fluid and viscosity: the coating, its solids and thickness; viscosity picks the tip family.
2. Film required: the wet or dry film you must lay; this sizes the orifice and the speed.
3. Part geometry: the surface and how it’s held; this picks the angle and the gun type.
4. Transfer requirement: HVLP for expensive material, airless for speed.

With those four, the quote comes back with a tip and a gun. Without them, every supplier picks blind.

Air Atomising Guns: When the Finish Is the Product

For the finest, most uniform finish, or a fluid too thick for a pressure tip, an air atomising gun uses compressed air to shear the material at the tip:

• Control: 10–60 µm drops at any flow; the finish is repeatable, and the droplet follows the air, not the material pressure.
• The cost: a compressor and the air bill; and more cleanup than a pressure gun.
• The choice: air atomising when the finish or the fluid demands it (fine coatings, two-part materials, viscous products); pressure or HVLP for the everyday job.

The air gun is the specialist; the airless and HVLP are the workhorses. Match the gun to the finish, not the habit.

The One-Paragraph Summary

A spray gun tip is pattern, orifice and atomisation: pick the angle for the part, the orifice for the film at your speed, the atomisation for the fluid, and hold the standoff, overlap 50%, and trigger off the part. Get those right and the coat is even; get them wrong and you are mopping overspray.

Quick Reference: Tip by Fluid

Fluid	Tip family	Why
Thin solvent coatings	HVLP 1.3–1.4 mm	Fine finish, low overspray
Water-based	Stainless tip	Chemistry attacks brass
Filled/abrasive	Tungsten carbide	Orifice survives
Thick gel/adhesive	Large-orifice airless	No starve
Primer/sealer	110° wide airless	Speed, flood
Fine topcoat	15–40° narrow	Precision, low build

Thirty seconds to the family, then the four numbers do the rest.

Troubleshooting: The Full Walkthrough

1. Sags and runs: too much material: tip too big for your speed, standoff too close, or too many passes. Narrow, back off, or lighten.
2. Orange peel: drops too coarse: pressure too low, wrong tip for viscosity, or too far. Raise pressure within rating, or finer tip.
3. Stripes (light and dark bands): standoff drift or uneven overlap. Lock the distance, overlap 50%.
4. Spitting: tip seat damage or a clogged passage. Clean, replace the seat.
5. Dry spray (dust): material drying before it lands: too fine a drop, too far, too hot. Coarsen, close in, or cooler conditions.

Ninety percent of finish complaints are pattern, film or droplet out of line: the four numbers, not the tip itself.

One Sentence Before You Spec

Tell the supplier the fluid and viscosity, the film you must lay, the part geometry, and whether the material is expensive enough to justify HVLP, and a gun tip spec writes itself. Withhold the viscosity and you get a tip that drips or starves on the first pass.

The Bottom Line on the Finish

A spray gun nozzle is the cheapest part of the finishing system and the one that decides the result: pattern for the part, orifice for the film, atomisation for the fluid, transfer for the material cost, then hold the standoff, overlap the passes, and clean the tip after every use. Get the four numbers right and the coat is even; get them wrong and the floor is the product.

Bottom Line

A spray gun nozzle is tip angle (pattern), orifice (flow) and pressure (finish). Pick the angle for the surface, the orifice for the fluid, the pressure for the atomisation, and hold the rated standoff. Do that and the coat is even; skip it and you are mopping overspray.

Need a tip rated for your fluid, film and fan angle? Send the duty to our enquiry form or compare the spray gun nozzle range.