There are few pieces of equipment as vital in the painting world as spray nozzles. No matter what kind of coating you’re spraying – stains, clear finishes, enamels, or latex paints – your nozzle determines everything from the width of your spray fan to the output of fluid. But unless you know how to decode a spray nozzle’s cryptic numbers, you’re flying blind.
In this beginner’s guide, as a professional spray nozzles supplier, we’ll break down that mysterious string of digits and letters so you can unleash the full power of your airless sprayer. You’ll learn how the numbers on a spray tip control spray fan width, material output, and more.
Why Understanding Nozzle Numbers is Essential
I’ll admit – for a long time, I was clueless about spray nozzles. As a newbie painter, those tiny engravings on the nozzle didn’t mean much to me. I assumed that as long as it physically fit on my sprayer, it must be “the right nozzle”.
And for simple DIY jobs, that logic sort of works. You can slap on an arbitrary nozzle and pray for passable results. But once I started taking on more complex professional jobs, picking the wrong spray nozzle led to disastrous outcomes.
I’m talking hours of rework sanding and stripping. Tons of wasted material from too much overspray or a fan pattern that was way too wide. And endless frustration trying to figure out why my finishes were coming out blotchy or grainy.
It all came down to picking the wrong nozzles. And once I cracked the code on those mysterious digits, it unlocked a whole new level of airless sprayer mastery.
Now I obsess over nozzle selection like a PGA pro obsesses over his clubs. Because when you use the right spray nozzle for your material and spray technique, everything gets easier.
So whether you’re a pro painter or just getting started with your first DIY project, learning how to pick the perfect nozzle is one of the best things you can do for your painting success.
Anatomy of a Spray Nozzle
To understand what those numbers and letters on your nozzle mean, let’s quickly walk through the key parts of a typical airless spray nozzle.
There are small differences between brands. But most modern nozzles have the same basic structure:
- A metal handle that connects to the gun. Usually marked with the brand name and model number.
- An aluminum guard that protects the nozzle. Guards come color coded to ID your nozzle’s spray angle.
- The actual nozzle tip made of hardened carbide steel. This has your all-important size markings.
- A seal at the base prevents paint from leaking backwards into the guard.
Now take a closer look at the tip:
You’ll usually see a string of numbers – something like 515 or 217. Along with a letter or two that identifies factors like the material or spray quality.
Decoding these markings is the secret to picking the right nozzle.
Breaking Down Nozzle Markings
Thanks to an international standard, most spray nozzle numbers follow consistent conventions across brands. Let’s take them piece by piece.
Spray Fan Width
The first digit in your nozzle’s number signifies one-half of the nozzle’s fan width. This width is measured when you hold the gun 12″ from the surface at a 90 ̊ angle.
For example, a 515 tip produces a spray fan 10″ across:
- First digit 5
- 5 x 2 = 10″ fan width
A 313 nozzle would create a narrow 6″ fan (3 x 2 = 6″). While a 729 tip sprays an extra wide 14″ fan (7 x 2 = 14″).
So by changing your first number, you control coverage area. Wider is faster for broad surfaces. Narrow focuses more oomph to dig into grooves and details.
Nozzle Orifice Size
The last two digits indicate the physical size of the nozzle orifice in thousandths of an inch. This tiny hole is the last stop for fluid before it atomizes and sprays onto your work.
Our 515 tip has a .015″ orifice (15 thousandths of an inch). A 211 would be significantly smaller at .011″. And a 639 extra large at .039″.
The bigger the orifice, the more fluid can pass through. So for heavy films you need big tips like .035″+. While thin materials like stains require tiny tips around .009-.013″.
Nozzle Material and Features
You’ll also see letters on most nozzles that give extra info about that specific model.
Materials are common, like:
- SS – Stainless Steel
- WC – Tungsten Carbide
- BR – Brass
Some other letters denote special tip features:
- LP – Low pressure
- FF – Fine Finish
- AV – Adjustable Valve to control flow
So a “517 LP WC” uses tungsten carbide for long wear at low pressures. While a “215 BR” is a brass tip good for common painting jobs.
Putting it All Together
Once you know what the numbers and letters represent, decoding any nozzle is simple:
- The first digit shows spray fan size
- The last two digits show orifice size
- Letters identify features and material
For example, a “513 LP SS” sprays a 10″ fan from a .013″ orifice. It works at low pressure and the tip itself is stainless steel.
Super easy, right?
Now that you can “speak nozzle”, let’s see how this all translates into choosing the best tip for your project.
Matching Nozzles to Materials
One key skill that separates the pros from DIYers is properly matching nozzles to whatever coating you’re spraying. As a quick cheat sheet:
- Thin materials – tiny tips (.009-.013″)
- Medium coatings – mid-sized tips (.013-.019″)
- Heavy fluids – big tips (.021″+)
But a better approach is to check the spray recommendations that come with your actual coating. Most have a chart right on the container or spec sheet.
For example, General Finishes suggests a .011″-.015″ tip at 1,000-1,500 PSI for their popular Arm-R-Seal Oil & Urethane Topcoat. So I’d grab a 311, 413 or 513 nozzle to start testing.
Follow the paint’s guidelines when available. But here is a handy chart with some ballpark starting points for various materials:
| Material | Nozzle Size |
|---|---|
| Clear Coat Lacquer | 009 – 011 |
| Varnish, Water Sealers | 009 – 013 |
| Shellac | 009 – 013 |
| Water Borne Lacquer | 012 – 014 |
| Clear Acrylics | 012 – 014 |
| 100% Acrylic Latex | 013 – 015 |
| Oil-based Enamels | 013 – 015 |
| Polyurethane | 013 – 015 |
| Interior Latex | 015 – 017 |
| Exterior Latex | 017 – 019 |
| Primer Latex/Oils | 017 – 019 |
| Heavy Latex | 021 – 025 |
| Elastomerics | 025 – 039 |
| Block Fillers | 025 – 039 |
I know that seems like a ton of stuff to memorize. But keep this chart handy, and after a few jobs you’ll have your most common sizes down cold.
Adjusting for Pressure & Speed
Fan width and orifice size are a great starting point for getting the right nozzle. But for truly dialed-in spraying, you also need to consider pressure and spraying speed.
Higher pressure forces more fluid through the nozzle. So you can use a smaller tip at 1,000 PSI vs 700 PSI and maintain the same output.
Slower pass speed also gives the coating more dwell time on the surface, increasing film thickness. While a quicker arm allows you to stretch output over more territory.
This is where the paint manufacturer charts really pay off. They suggest not just a tip size, but optimal pressure and wet film thickness too.
If coming up with your own parameters, a good formula to remember is:
- 1,000 PSI with a 12 inch per second pass speed deposits around 1 mil of coating per coat.
So for a 2 mil finish, make two passes at those baseline settings. Or up the fluid flow to deposit it heavier on a single go-round.
No matter what numbers you land on, be methodical with pressure changes in 50 PSI increments. And control speed using consistent arm movements. This keeps results consistent while honing in on your best nozzle/setting combo.
Why Spray Nozzles Matter More Than Your Gun
As a beginner, I put tons of thought into choosing the perfect spray gun. And quality guns are important – don’t get me wrong.
But what I didn’t realize is that your nozzle matters 100X more than your gun when it comes to the actual spraying process. You can connect an amazing Graco Silver Plus to some random nozzle and still fight frustrating results.
Yet combine a no-name spray gun with the right tip for your project and the outcome can be flawless.
It comes down to this:
Your gun is just a delivery mechanism. It’s the nozzle that takes over atomization duties right before that mist of paint reaches your work.
So upgrade your gun for comfort and reliability. But obsess over nozzle selection to unlock the true potential of any airless spray system.
Decoding Nozzle Catalog Numbers
The last piece of demystifying spray nozzle numbers is learning a brand’s cataloging system.
Typing a bunch of random digits into a search box is annoying. But when you understand the logic behind a nozzle series, finding alternatives is simple.
Let’s use Graco’s RAC X tips as an example:
- The “R” means fully reversible to clear clogs
- “AC” = Airless Compatible
- “X” signifies advanced technology
Then you have the size number – RAC X FF LP 217:
- “FF” = Fine Finish low pressure
- “LP” = Low Pressure
- “217” = 6″ fan width, .017″ orifice
So if I want to experiment with a narrower fan, I’d search for another RAC X FF LP tip…maybe a RAC X FF LP 315. Same features and pressure rating, just adjusted for a 4″ spray pattern.
Catalog logic varies by brand. But once you pick up on the shorthand, finding alternate nozzles is a breeze.
Wrapping Up
As you can see, the string of numbers and letters on your spray nozzle packs a ton of meaningful info. Translate them correctly and you unlock precise control over sprays fans, film thickness, and atomization.
This might seem complex when you’re just getting started. But before long, reading nozzle markings becomes second nature.
So refer back to this guide whenever decoding a new nozzle. With some hands-on practice, you’ll be spraying like a pro in no time.
Thanks for reading – let me know if you have any other painting questions!
