Airless Spray Tip Selection
How to read airless tip codes and match orifice size and fan width to the coating, the pump and the shape of the work — and when a worn tip is costing you money.
Key takeaways
- An airless tip controls two things: flow rate (set by the orifice size) and fan width (set by the tip’s cut angle).
- In the common three-digit code, the first digit doubled gives the approximate fan width in inches at 12 in (300 mm), and the last two digits are the orifice in thousandths of an inch.
- Choose the orifice for the material’s viscosity and the film build you need, and the fan width for the shape of the surface.
- Tips wear: the orifice grows and the fan shrinks, increasing film build and waste. Replace tips on a schedule, not when the pattern is already ruined.
The spray tip is the smallest and cheapest part of an airless spray system, yet it has an outsized effect on productivity and film quality. The same pump and gun can lay down a fine-finish lacquer or a heavy epoxy mastic depending entirely on which tip is installed. A poor choice causes tails, sags, dry spray, wasted material and fatigue for the applicator.
This article explains how tips are coded, how to select one for a given coating and surface, and how to manage wear.
Reading tip codes
Most North American airless tips use a three-digit number. Using a 517 tip as an example:
- First digit (5) — multiply by two for the approximate fan width in inches when the gun is held 12 in (300 mm) from the surface. A 5 gives roughly a 10 in (250 mm) fan.
- Last two digits (17) — the orifice diameter in thousandths of an inch, here 0.017 in (about 0.43 mm).
Some manufacturers, particularly in Europe, express fan size as a spray angle in degrees instead. Fan width also changes with gun distance and with pressure, so the printed figure is a nominal value measured under defined test conditions. Always check the manufacturer’s chart for the exact convention.
Flow rate rises with orifice area, not diameter. Moving from a 0.017 in to a 0.021 in orifice increases the area — and approximately the flow at the same pressure — by around half, so small changes in the code make big changes on the wall.
Choosing the orifice size
The orifice must be large enough for the coating to flow and atomize at a reasonable pressure, but small enough to control film build. Thicker, higher-solids and filled materials need larger orifices; thin stains and sealers need small ones. The coating’s product data sheet usually lists a recommended tip range and is the first place to look.
| Material type | Typical orifice range | Notes |
|---|---|---|
| Stains, sealers, lacquers | 0.009–0.013 in (0.23–0.33 mm) | Low viscosity; fine-finish tips common |
| Alkyd and acrylic enamels | 0.011–0.015 in (0.28–0.38 mm) | Light industrial and architectural work |
| Latex wall paints, primers | 0.015–0.019 in (0.38–0.48 mm) | General architectural |
| Industrial epoxies and urethanes | 0.015–0.023 in (0.38–0.58 mm) | Varies widely with solids and viscosity |
| High-build mastics, elastomerics | 0.021–0.035 in (0.53–0.89 mm) | Heavy, filled or fibrous materials |
These ranges are starting points. The coating’s viscosity, temperature and solids content, along with hose length and pump capacity, all shift the right answer. A pump also has a maximum tip size it can support; exceed it and pressure will drop and atomization will suffer.
Choosing the fan width
Fan width should match the work, not the applicator’s wish to finish quickly.
- Narrow fans (roughly 4–8 in, 100–200 mm) suit structural members, flanges, pipe and other narrow shapes, and are useful for stripe coating by spray where the specification allows it.
- Medium fans (roughly 10–12 in, 250–300 mm) are general-purpose for walls, tank shells and plate.
- Wide fans (14 in, 350 mm and up) speed coverage on large, flat surfaces such as roofs, floors and hulls, but require a pump with enough capacity to atomize the larger total flow.
For two tips with the same orifice, the wider fan spreads the same flow over a larger area, so it lays down a thinner wet film per pass at the same gun speed. That relationship is a useful lever: if a coat is sagging, a wider fan with the same orifice may cure the problem without changing the gun speed.
Tip types and features
- Reversible tips rotate 180° in the guard so a clog can be blown out by spraying backward, then turned forward again. They are standard on most modern guns.
- Fine-finish tips incorporate a pre-orifice that helps atomize at lower pressure, producing a softer pattern with less overspray.
- Low-pressure tips are designed to atomize at reduced pressure, extending pump and tip life.
- Flat tips are used in some industrial and fixed-installation applications and in some multi-gun setups.
Plural-component guns use tips or mix chambers matched to the proportioner; see plural-component spray equipment for those systems.
Never remove the tip guard or point the gun at anyone. Airless pressures can inject fluid through skin. Always relieve pressure and engage the trigger lock before changing or clearing a tip.
Tip wear and replacement
Carbide tips wear as abrasive pigments pass through them. The orifice enlarges and rounds, so flow increases while the fan narrows. The applicator often compensates by raising pressure, which accelerates wear further and increases overspray. Worn tips quietly waste material and raise film build beyond the specification, especially with highly filled primers.
- Record a baseline. Spray a test pattern on cardboard at the working distance and pressure with a new tip, and note the fan width.
- Check regularly. Repeat the test pattern periodically during production.
- Replace on schedule. When the fan has narrowed noticeably — many crews use a loss of about a quarter of the original width as a trigger — replace the tip.
- Verify film build. After any tip change, confirm the coat with wet film thickness readings.
Cleaning tips promptly after use and storing them in the appropriate solvent or water also extends their life.
Frequently asked questions
What does a 621 tip mean?
In the common convention, it gives a fan of roughly 12 in (300 mm) at a 12 in gun distance and has an orifice of 0.021 in (about 0.53 mm).
Should I use a bigger tip to go faster?
Only if the pump can support it and the film build stays in specification. A larger orifice delivers more material per second, which can lead to sags and overbuild unless gun speed and fan width are adjusted.
Why does my pattern have heavy bands at the edges?
These “tails” usually mean pressure is too low for the tip and coating, the material is too viscous or cold, or the tip is worn. Increase pressure within limits, condition the material, or try a smaller or fine-finish tip.
How long does a tip last?
It depends on the coating’s abrasiveness and pressure. Tips may last for many hundreds of gallons with light architectural paints but wear much faster with zinc-rich or highly filled primers.
Educational reference. Coating performance varies by formulation. Always follow the manufacturer’s product data sheet, safety data sheet and your project specification.
