Airless Paint Spraying: Pressure, Tip Size and Technique That Decide the Finish

Paint sprayer supplies, spare tips, filters, swivel seals and solvent, run roughly 5–10% of the machine price per year; buy them with the machine.

Paint sprayer replacement parts that matter: the tip (wears and widens the fan), the filter (plugs and starves the tip), the seal kit (leaks and drops pressure), and the hose (restricts flow when kinked). Keep a tip and filter set per gun.

An air sprayer paint setup (air-atomized) gives the finest finish but lower transfer efficiency, 30–45% versus 50–70% for airless, so lines pick airless for speed and air spray for appearance coats.

Coating spraying on an industrial line shares the same physics as airless painting: film thickness follows flow divided by coverage area, so a 10% speed change on the conveyor requires a 10% flow change to hold the same dry film thickness.

A clean spray paint nozzle is a productivity tool, not a nicety: a partially blocked tip can cut flow by 30–50% while the pump keeps running, and the resulting fan distortion shows up as tiger stripes on the job. Soak the tip in solvent or a tip-cleaning brush kit between coats rather than wiping the orifice with metal.

Choosing an airless paint sprayer gun means matching the tip, filter and hose to the pump: a 0.017-inch tip at 200 bar delivers roughly 1.2 L/min, and going up one tip size raises flow by about 30% at the same pressure. The paint sprayer tip size chart breaks the three-digit code into fan width and orifice, with the published flow table behind it.

The Short Answer
How Airless Spraying Works
Airless vs Air Spray: What Each One Buys You
Decoding the Tip Number
Choosing a Tip: Coating First, Then Machine
Setting Pressure the Right Way
Spraying Technique That Holds Up
Worked Example: How Long Will 2,000 ft² Take?
Why Tips Wear Out (and What It Costs)
Common Problems and Fixes
Safety: The Part Nobody Skips Twice
FAQ
Pre-Spray Checklist
The Bottom Line

The Short Answer

Airless paint spraying is the fastest way to put a thick, uniform coating on a large surface. Instead of compressed air, a pump pushes paint at 1,500 to 3,000 psi through a precision carbide orifice, and the pressure drop alone shreds the paint into droplets. No air is mixed into the stream, which is why it is called “airless.”

The finish you get is decided by three levers, in this order:

Tip selection: the two numbers on the tip set how wide the fan is and how much paint leaves the gun.
Pressure: set it as low as the coating will atomize; pressure is for atomization, not for speed.
Technique: distance, angle, stroke speed and overlap. A perfect tip at the wrong distance still runs or dry-sprays.

Get those three right and airless paint spraying beats brush and roller on speed by a factor of three to five, lays down films thick enough to cover in fewer coats, and does it with less overspray than conventional air spray. Get them wrong and you get tails, runs, orange peel and a redo.

How Airless Spraying Works

An airless paint sprayer has four working parts: a pump, a hose, a gun and a tip. The pump (piston or plunger, electric or gas driven) raises the coating to 1,500–3,000 psi (some industrial units run higher). The hose carries that pressure to the gun, and the gun’s trigger either blocks or releases it. The tip is a small tungsten carbide disc with a precisely ground slot, and it is where atomization happens.

When the trigger opens, paint is forced through the slot, and the emerging sheet of fluid widens into a flat fan that tears into droplets. Fan width, droplet size and edge definition all come from orifice geometry and pressure, not from air. That is the defining difference from air spray.

The physics is worth knowing because it explains why the machine behaves the way it does. Fluid leaving the orifice obeys Bernoulli: velocity v = √(2·ΔP/ρ). For water at 2,000 psi (13.8 MPa), that is roughly 166 m/s; at 3,000 psi (20.7 MPa) it is about 203 m/s. Nothing sprays: the paint is injected out at hundreds of metres per second and tears itself apart.

Flow through the tip follows Q = Cd·A·√(2·ΔP/ρ), flow is proportional to orifice area and to the square root of pressure:

Double the pressure, flow rises 41% (√2 = 1.41), not 100%. This is why cranking pressure to “get more paint out” is the wrong move: you get a little more flow, a lot more overspray, and faster tip and pump wear. If you need more flow, change the tip.
Orifice area grows with the square of diameter. A tip that goes from 0.015″ to 0.021″ (1.4× the diameter) has 1.96× the area, roughly double the flow at the same pressure. That matches the published flow tables, which is why tip size dominates everything else.

Two practical consequences follow. First, atomization quality is pressure-driven: too little pressure and the sheet does not tear fully, giving “tails” and strings at the pattern edges. Second, the fan is a dense hydraulic sheet that lays down a wet film immediately, exactly what high-solids and thick coatings need.

Airless vs Air Spray: What Each One Buys You

The choice is not “better,” it is “better for what.” Airless exists to move volume; air spray exists to move finish quality.

	Airless	Conventional air spray	HVLP
Atomizing energy	Hydraulic pressure	Compressed air	Low-pressure air
Typical fluid pressure	1,500–3,000+ psi	10–50 psi	~10 psi at air cap
Transfer efficiency	~50–65%	~30–40%	≥65% (SCAQMD threshold)
Application rate	Fastest	Slow	Slow
Film build per coat	Thick; 20+ mils with heavy tips	Thin	Thin
Finish smoothness	Good, slight orange peel	Smoothest	Very smooth
Best fit	Large surfaces, high-solids, elastomeric	Furniture, automotive	Fine finish, regulated areas

HVLP is defined by the SCAQMD/EPA threshold of 65% transfer efficiency at air cap pressure at or below 10 psi; conventional air spray sits around 30–40% because much of the paint bounces off in overspray; airless lands between the two, typically 50–65% depending on pressure, tip and operator. That is why airless paint spraying is the default for exterior walls, fences, steel, tanks, block filler and elastomeric coatings: it puts thick material down fast and wastes less than air spray doing it.

Air spray’s advantages are real but narrow: the finest finish (furniture, automotive), finer detail control, and thin films where needed. If a job is 2,000 ft² of wall, airless wins on every axis except pump price. A good rule: choose airless when the surface is large or the coating is thick; choose air spray when the finish is the product.

Decoding the Tip Number

Every major airless tip, Graco, Wagner, Titan and most others, uses the same three-digit code, and once you can read it you can spec any job. The code means:

First digit × 2 = fan width in inches at 12″ from the surface. A “5” sprays a 10-inch fan, a “3” sprays 6 inches, a “7” sprays 14 inches.
Last two digits = orifice size in thousandths of an inch. “15” is 0.015″, “17” is 0.017″.

So a 515 tip produces a 10-inch fan from a 0.015″ orifice, and a 517 tip produces the same 10-inch fan from a 0.017″ orifice. The two numbers are independent: a 317 and a 517 both have a 0.017″ orifice, but the 517 spreads that same flow over a 10-inch fan instead of 6 inches, a thinner film per pass, which is how fan width sets mil build.

The commonly quoted flow table (water at 2,000 psi / 13.8 MPa, from Graco-type tip charts; higher-viscosity coatings flow less):

Tip	Orifice	Fan at 12″	Flow @ 2,000 psi	Typical use
209	0.009″	4″	0.09 gpm	Lacquer, varnish, clear sealer, wood stain
311	0.011″	6″	0.12 gpm	Stains, lacquers, urethanes
413	0.013″	8″	0.18 gpm	Enamels, primers, thin acrylics
515	0.015″	10″	0.24 gpm	Standard latex, acrylics, oil-based primers
517	0.017″	10″	0.31 gpm	Latex with heavier build, exterior
619	0.019″	12″	0.38 gpm	Heavy latex, large exteriors
623	0.023″	12″	0.57 gpm	Block filler, thick primers
727	0.027″	14″	0.77 gpm	Elastomeric, texture

Manufacturers also color-code families: blue/black for general use, green for fine finish, neon for low-pressure fine-finish tips, yellow for striping, grey for heavy-duty high-pressure tips. The colour is branding; the three digits are the spec that matters.

Choosing a Tip: Coating First, Then Machine

Tip selection has three constraints, in this order: coating viscosity sets the orifice, surface size sets the fan, and pump capacity sets the ceiling.

1. Coating → orifice. Thin material needs a small orifice, thick material needs a big one. If the orifice is too small for the coating, the tip clogs and the pump stalls; too big, and you get a heavy, sagging film you cannot control. The widely used coating-to-orifice ranges:

Coating	Orifice range
Lacquer, stain, clear sealer	0.009″–0.013″
Oil-based paint	0.013″–0.015″
Latex paint	0.015″–0.019″
Heavy latex, smooth elastomeric	0.021″–0.025″
Elastomeric, block filler	0.025″–0.035″+

2. Surface size → fan width. Small surfaces and trim need a narrow fan so overspray stays low: 4–6″ fans for doors, cabinets and trim; 8–10″ for general interior and exterior work; 12–14″ for large walls and production exteriors; 24″ “wide” tips exist for high-production flatwork, but need a pump with enough flow to keep a full pattern. Fan width also interacts with distance. See Spraying Technique That Holds Up.

3. Pump capacity → ceiling. Every pump is rated for a maximum flow in gallons per minute. The tip’s flow at your operating pressure must stay at or below that rating. Oversize the tip and the pump cannot hold pressure. Atomization collapses, you get tails, and the pump cycles hard and wears early. Undersize it and you just spray slowly, which is safe. When in doubt, pick the tip whose flow sits around 80% of the pump’s rating.

Filters follow the orifice. Gun and pump filters are matched in mesh so they catch particles smaller than the orifice will pass. A 0.015″ tip with a coarse filter lets grit straight through to clog the tip. The standard pairing: 200-mesh (red) for 0.006″–0.013″ tips, 100-mesh (blue) for 0.013″–0.015″, 60-mesh (black) for 0.015″–0.029″, 30-mesh (grey) for 0.029″ and up. A reversible tip (the “RAC” style) clears most clogs by flipping 180° and triggering, worth it on most jobs.

Setting Pressure the Right Way

The single most common pressure mistake is cranking the dial. The rule, from every equipment manufacturer’s training material, is: use the lowest pressure that produces a fully atomized pattern. More pressure does not mean better coverage. It means more overspray, faster tip wear and a shorter pump life.

The procedure is the same every job:

Start at the low end of the machine’s range and spray a test pass on cardboard or scrap.
Look at the pattern edges. Tails, streaks or strings at the fan edges, mean the coating is not fully atomizing. Raise pressure in roughly 500 psi steps until the fan is a clean, even sheet edge to edge.
Once the pattern is clean, stop. That is your working pressure.

Typical working pressures for architectural latex land around 1,500–2,200 psi; fine-finish work runs higher. The tip number encodes the working pressure class. Match the tip to the pump’s pressure window, not the other way round.

Remember Q ∝ √P: going from 2,000 to 3,000 psi adds only about 22% more flow through the same tip. Want more output? Change the tip, not the dial.

Spraying Technique That Holds Up

Technique is where most of the difference between a professional finish and a “painter’s first job” finish lives. The rules, from Wagner’s and Graco’s published technique guides, are consistent:

Distance: 10–14″ (25–35 cm) from the surface. Too far and the fan widens, the pattern thins and fades, and overspray climbs; too close and the paint lands too concentrated and runs. Fan width is rated at 12″, so that is the anchor distance.
Keep the gun at 90° to the surface. Arcing the wrist makes the distance vary across the stroke, which means a heavy pass in the middle and a thin, dry pass at the ends. Move your whole body, not your wrist.
Move at a constant speed. Inconsistent speed = patches and streaks. Spray in horizontal or vertical passes, whichever suits the surface, but keep the speed even.
Trigger discipline: start moving, then pull; release, then stop. Pulling the trigger while the gun is stationary dumps paint into one spot, a guaranteed run. Start the stroke, trigger, and release the trigger a moment before you stop the stroke.
Overlap each stroke by about 30%. This is the difference between a streak-free result and zebra stripes. A 10″ fan overlapped 30% gives an effective ~7″ of fresh coverage per pass.
Keep a wet edge. Work in sections and keep the boundary between sprayed and unsprayed area wet so the next pass blends in. Stopping to think in the middle of a wall leaves a dry seam.

If you are coming from brush and roller, the mental shift is that the tool sets the film thickness, not you. Your job is to move it evenly; the tip and pressure decide how much paint lands. On exteriors, many contractors back-roll after airless paint spraying to knock down orange peel and press paint into the substrate, a legitimate finish step, not a failure of the sprayer.

Worked Example: How Long Will 2,000 ft² Take?

Let’s put the numbers together. You are spraying a 2,000 ft² exterior with latex at 4 mils wet film, using a 515 tip (0.24 gpm at 2,000 psi).

First, how much paint is needed. One gallon is 231 in³. A 4-mil wet film over 2,000 ft²:

Area in in²: 2,000 × 144 = 288,000 in²
Wet volume: 288,000 × 0.004 = 1,152 in³
At 100% transfer: 1,152 / 231 = 4.99 gallons

Nothing sprays at 100% transfer. At a realistic 60% transfer efficiency for airless, that becomes 8.3 gallons of material actually leaving the gun. At 0.24 gpm, trigger-on time is 8.3 / 0.24 ≈ 35 minutes. Pure trigger time, that is. Setup, masking, repositioning and the 30% overlap add on, so budget a couple of hours for the spraying itself. The same wall with a roller is a full day, and with a brush, two.

Now the speed claim. A 10″ fan at 12″ moving at 3 ft/s covers 10″ × 36″/s = 360 in²/s ≈ 2.5 ft²/s of raw strip; with 30% overlap the effective strip is ~7″ wide, so ~1.75 ft²/s ≈ 6,300 ft²/hr. Nobody holds that rate all day, trigger-off turns and repositioning cut it hard, but it shows the ceiling airless operates near.

Why Tips Wear Out (and What It Costs)

Tips are tungsten carbide, the hardest practical material for the job, but every coating contains abrasive solids, titanium dioxide, silica, zinc, and they machine the orifice wider over time. The failure mode matters because it is invisible: as the tip wears, the orifice grows and the fan narrows. You get more paint per pass through a smaller effective fan, which means heavier film, runs, and more passes to cover the same area. The pattern degrades gradually, so crews keep spraying through it.

Published wear-life figures (approximate, coating- and tip-size-dependent, from airless tip selection literature): clear lacquers last around 400 gallons, latex between 75 and 250 gallons depending on tip size, block filler 75–250 gallons, and abrasive road-marking paint as little as 20–200 gallons. High pressure accelerates wear; running at the lowest good pressure is the single biggest tip-life lever, which is also why low-pressure tips double tip life while spraying at half pressure.

The cost of ignoring it is real. Graco’s worked example: paint at $15/gal, labor at $25/hr, spraying 5 gallons/hour. A tip worn from a 12″ fan down to a 9″ fan wastes about $36 per hour in extra paint and labor, roughly $300 in a working day. Other industry sources put a worn tip’s extra paint consumption at around 25%. A $30–60 tip is the cheapest insurance on the rig.

The check takes ten seconds: spray onto cardboard and look at the pattern. A clean, even fan edge to edge means the tip is fine. A narrowing fan, fading edges or a heavier center stripe means replace it. Keep a spare in the truck. Worn tips fail on the job, not before it.

Common Problems and Fixes

Symptom	Root cause	Fix
Tails/strings at pattern edges	Pressure too low for coating; tip too large for pump; worn tip	Raise pressure in 500 psi steps; downsize tip to pump rating; replace worn tip
Runs and drips	Gun too close; stroke too slow; heavy film from oversized orifice	Hold 10–14″; keep stroke speed even; downsize orifice
Dry, powdery, “dusty” finish	Gun too far; pressure too high; thinning too aggressive	Close distance; drop pressure to lowest good pattern
Orange peel	Pressure too low; coating too cold or viscous; poor thinner match	Raise pressure slightly; warm coating; correct thinning per label
Heavy center stripe, thin edges	Worn tip (fan collapsed)	Replace tip
Clogging	Wrong filter mesh; dried paint; too-small orifice for coating	Match mesh to orifice; strain paint; use reversible tip
Surging / spitting	Clogged inlet filter; kinked suction hose; pump cavitation	Clean filters; straighten hose; check pickup tube

Notice how many of these are system problems, not tip problems. If a new tip still tails, the machine or the coating is the problem. Diagnose before you buy parts.

Safety: The Part Nobody Skips Twice

Airless paint spraying is the one spraying technology where a safety mistake can cost a finger or a hand, so treat this section as the most important in the guide.

Injection injury is the big one. Fluid at 1,500–3,000 psi can penetrate skin, and skin can be breached at pressures as low as 100 psi. An airless injection looks like a small puncture, but the paint is inside the tissue, and the injury is surgical: if fluid enters a finger or hand, go to an emergency room immediately and tell them it is a high-pressure injection. Delay measured in hours can mean amputation. It does not hurt much at first; that is the trap.

The rules that prevent it:

Never point the gun at any part of your body: not to test, not to clear, not “just for a second.”
Never check for a leak with your finger. Look, don’t touch. A pinhole leak at 2,000 psi cuts like a scalpel.
Keep the tip guard on. It is not a convenience; it is what stops a misdirected stream.
Engage the trigger lock whenever the gun is not in your hand.
Relieve pressure before any cleaning or tip change: lock the trigger, turn the pump off, then trigger into a waste pail until nothing comes out. The hose holds the full working pressure even with the pump off. A pressurized hose is a pressurized gun.
Never clear a clog by holding your hand over the tip or pressing it against a surface to blow it backward. Use the reversible tip, or relieve pressure and remove the tip.

Then the standard coating hazards: a NIOSH-approved respirator for solvent and isocyanate exposure, overspray is aerosol, and fine droplets are easy to breathe, plus safety glasses, gloves, coveralls and ventilation. Solvent-based materials need spark-safe handling: no smoking, grounded equipment, vapor-safe lighting. Overspray travels further than you think; mask everything you want to keep.

FAQ

What pressure should I use for airless paint spraying? The lowest pressure that fully atomizes the coating, typically 1,500–2,200 psi for architectural latex, higher for high-solids and elastomerics. Set it by testing the pattern, not by habit.

How far should I hold the gun from the surface? 10–14″ (25–35 cm), perpendicular to the surface. Fan width is rated at 12″, so that distance is your reference.

What tip do I use for latex paint? 0.015″–0.019″ orifice, a 515 or 517 for general work, 619 for heavy exterior builds. Thin coatings (stains, lacquers) take 0.009″–0.013″; elastomerics and block filler take 0.025″+.

How do I read the numbers on an airless tip? First digit × 2 = fan width in inches at 12″; last two digits = orifice in thousandths of an inch. A 515 sprays a 10″ fan through a 0.015″ orifice.

Why am I getting tails at the edges of the pattern? Not enough pressure for that coating and tip, the tip is too large for the pump, or the tip is worn. Raise pressure in 500 psi steps first; if that fails, check tip size and wear.

How long does a tip last? Coating-dependent: roughly 400 gallons with clear lacquers, 75–250 gallons with latex, as little as 20 gallons with abrasive road paint. Lower pressure extends life; a worn tip wastes paint and labor far faster than a new tip costs.

Pre-Spray Checklist

The Bottom Line

Airless paint spraying is a hydraulic process with three independent levers: tip (fan width + orifice), pressure and technique. Choose the tip from the coating and the pump, set pressure to the lowest fully atomizing value, and spray at 10–14″ with a 90° angle, even speed and 30% overlap. The finish beats brush and roller on speed and air spray on waste. Tips wear invisibly and expensively. Check the pattern on cardboard, not the calendar. And every job: at 2,000 psi, the gun is a tool that demands respect. If you are speccing guns, tips or lances for a coating line or a contracting crew, our spray gun range covers the hand-held end, and the nozzle wear guide explains the same erosion math that destroys airless tips, or talk to us about your application and we will work the numbers with you.