Selecting the right spray tip for the job

How to select the Best Spray Gun Tips For Your Paint Job

The Spray tips that you use for your airless spray job can make or break your finish. This How-To guide explains why choosing the right spray tip is important, how the three-digit code system works, and which tips are suited to which types of paint job.

Why choosing the right Spray Tip is important

Using the wrong spray tup can severly affect productivity and user satisfaction. When a tip is too large, it causes overspray, sags, runs and an all-round poor finish.  This is problematic for several resons:

  • Overspray wastes product and reduces profitability
  • Re-Working paint jobs is costly and creates production line bottlenecks
  • Painters take pride in their work and re-working is demotivating

Using the correct tip can prevent all of these issues

How do spray gun tips work?

The first step to identifying the best tip for your job is understanding how airless spray gun tips work.

As the name suggests, an airless spray pump pressurieses paint without the use of air. Instead, the coating is forces through the spray tip orifice under extreme pressure.  This process atomises the paint and spray particles exit the gun in a fan pattern.  The size of the orifice determines the flow rate and width of the fan pattern.

Airless spray tips 3-digit system

The key to knowing which airless spray nozzle to use is understanding the 3-digit number that is printed on the tip. In the example below, you can see the number is 517.  The first digit (5) times 2 (10inch) gives you the fan width when spraying 12 inches away from the surface of the substrate.  The following two digits (1 and 7) make up the number 17, which indicates the orifice size in thousandths of an inch (17 thousandths of an inch).

Working out the spray angle

The first number of the 3-digit sequence represents the spray angle in degrees. Add a zero to the digit to get the angle.

Examples:

  • 2xx = 20 degrees
  • 3xx = 30 degrees
  • 4xx = 40 degrees
  • 5xx = 50 degrees

How to calculate the fan width

Imperial calculaition:

Multiply the first digit by 2 = x fan width

So, in the case of the 517 tip, the calculation would be: 5 x 2 = 10-inch fan width

Metric Calculation:

Multiply the first digit by 5 = x inch fan width

In the case of a 517 tip, the calculation would be@ 5 x 5 = 25cm fan width

NOTE: The fan width is based on holding the gun 12 inches (30cm) away from the workpiece

Working out the orifice size

The second two digits in the 3-digit sequence tell you the diameter of the tip orifice in thousandths of an inch. So, a 517 tip has an orifice diameter of 0.017 inches, expressed as 17 thou.  To convert inches to centimetres, multiply by 2.5.

Example:

0.017 inches x 2.5 = 0.0425cm

NOTE: Always check the manufacturer's details for your airless sprayer as they will often state a maximum tip size

The combination of fan pattern and orifice size will determine the thickness of your coating. Your actual flow rate will depend on your spraying pressure, and the type of paint you are using: high pressure equals high flow; heavier paints equals low flow.

Your choice of tip will depend on several factors:

  • Size and surface of item that you are coaitng
  • Level of finish that you wish to achieve
  • Type of product that you are using

How to select the correct spray gun tip for your workpiece

poxIf everything in your production line is of the same type and size and uses the same product coaitng, you can take a 'one size fits all' approach to choosing your spray tips. For paint shops that spray items of different sizes from large flat panels to small, intricate components, you will need a range of tips to achieve the best possible finish.

Choosing the spray tips based on what you are coating

The size the item that you are spraying will influence the airless spray gun tip that you use. Here are some general rules of thumb for common types of workpiece:

Type of Workpiece Spray tip number

Intricate components

These require a low volume and narrow fan width

209 for a 4-inch fan width and a 9 thou orifice size

Shipping containers

These require a large tip to provide a consistent spray fan and reliable flow of paint

517 for a 10-inch fan width and a 17 thou orifice size

Structural steel

The majority of structural steel workpieces are beams and columns that require a specified thickness of paint film, but you are also likely to have flanges and brackets thrown into the mix.

317 for a 6-inch fan width and a 17 thou orifice size

Agricultural machinery & construction plant equipment

These types of workpiece involve multiple moving parts and intricate components. They are often high-value items that demand a flawless finish, for which a fins spray pattern and even paint flow is necessary.

The fan pattern needs to be in the range of 6-8 inches, so the first digit would be between 3-4. The orifice size will vary depending on the type of product being applied.  As a general guide, a 413 tip suits a multitude of agricultrual machinery and construction plant equipment workpieces.

NOTE: It is good practice to test-spray a few workpieces with different tips to gauge which one delivers optimal results

Choosing spray tips based on the type of coating

Often the type of coating will dictate the tip diameter. For example, high-volume solid paints can only pass through tips with a large orifice.  Always check the product datasheet for information on spray tip requirements.

Here are some generally recommended tip sizes for common types of coatings:

Product Type Orifice Size (thou) Product Type Orifice Size (thou)
Acrylics 100%, latex int 13-15 Membrane (Heavy) 23-27
Acrylics (clear) 13-15 Membrane (Very Heavy) 29-39
Block Fillers 25-39 Oil-based paints 13-15
Elastomeric polymers 25-39 Polyurethanes 13-15
Elastomeric polymers 21-25 Primers (latex) 15-17
Enamels (oil-based) 13-15 Primers (oil-based) 17-19
Epoxy 17-21 Sealers 17-21
Epoxy (heavy) 23-27 Shellac (clear) 09-13
Epoxy (high-solids) 29-39 Stains (solid) 13-15
Heavy Latex 21-25 Stains (transparent) 11-13
Lacquers (clear coat) 09-11 Tung Oil (pure thinned) 11-13
Lacquers (water-borne) 13-15 Varnishes 09-11
Latex Paint (exterior) 17-19 Varnishes (low-VOC) 13-15
Latex Paint (interior) 15-17 Water Sealers (thin, clear) 11-13
Membrane 17-21    

Buy your airless spray gun tips at Ultrimax

We stock a wide range o high-quality airless spray guns and tips. Visit the Ultrimax Online Store to buy today!

 

Need some more help with Spray Tips?

Why not get some help from our business specialists at Ultrimax, who can advise on choosing the correct spray tip for the job?

If you can't find a solution, give us a call and we'll get your paint shop on track.

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