Choosing the right nozzle size is crucial for properly spraying roof coatings. The nozzle opening determines fan width and material flow rate – so picking the wrong one can lead to a lousy finish or pump damage.
In this complete guide, as a professional spray nozzles supplier, I will share how to select the perfect nozzle for elastomeric roof coatings and smooth coatings.
How Nozzle Size Impacts Your Roof Coating Project
The nozzle opening size significantly impacts:
- Coating texture and thickness
- Overspray and material waste
- Coverage speed
- Tip clogging likelihood
Plus, oversized nozzles strain pumps – costing you money from repairs or replacements.
Undersized nozzles lead to frequent clogs, thin coverage, increased passes, and frustration.
Clearly, the nozzle must match coating thickness and sprayer output to achieve high-quality, efficient application.
What Size Nozzle to Spray Roof Coating?
Deciphering Nozzle Sizes
Spray tips feature a three-digit code defining fan width and orifice diameter.
First digit x 2 = fan width
A 413 tip sprays an 8-inch fan at a 12-inch distance.
Second two digits = orifice diameter in thousandths of an inch
A 415 tip has a .015″ orifice diameter. This opening meters coating volume.
Larger orifices flow more material. But material thickness ultimately determines ideal orifice size.
Match Nozzle Size to Coating Type
Roof coatings fall into three thickness categories – primers, smooth fabrics, and elastomeric coatings.
Primers: Penetrating primers prep and fortify aged roofs before coating application. Spray primers have a milk-like consistency – similar to latex paints. They require a .015″ – .019″ orifice nozzle.
Smooth Coatings: Flexible, acrylic-based coatings form a waterproof, protective barrier. Smooth fabrics have a thicker consistency than primers. Ideal nozzle sizes range from .019″ – .023″.
Elastomeric Coatings: The thickest roof coatings, elastomerics offer maximum weather protection. These rubber-like coatings have a paste-like consistency requiring wide spray nozzles. Ideal sizes range from .027″ – .035″.
Using a nozzle that’s too small leads to excessive tip clogs and thinning of thick coatings. Oversized nozzles strain pumps.
Follow manufacturer guidelines for best results.
Sprayer Tip Recommendations
Choosing nozzle sizes also depends on your sprayer model. More powerful rigs output more GPM for handling thicker materials without strain.
Here are common elastomeric nozzle sizes by spray rig:
- Graco 490 (0.95 GPM): 521 – 621
- Graco Ultra Max 695 (1.25 GPM): 521 – 623
- Graco Ultra Max 795 (1.75 GPM): 623 – 625
- Graco GH 230 (2.3 GPM): 629 – 635
Larger units like gas-powered rigs can pump out 3+ GPM for heavy coatings. More output requires bigger nozzles up to .045″.
Adjust Nozzle Size As Needed
The best way to dial in spray application is testing different nozzle sizes.
If you experience heavy tailing, too much overspray, or thin/incomplete coverage – install a larger or smaller tip.
Finding the optimum size for your coating thickness and rig output leads to uniform appearance and efficient application.
Match Fan Width to Surface Area
Fan width controls the spray pattern size.
Narrow fan widths – 4″ to 8″ work well for coating roof penetrations, pipes, small equipment curbs, and perimeter areas.
For quickly covering large areas, choose tip sizes producing 10″ to 12” fans. Wider fan spray tips speed production on bigger projects.
Adjust nozzle fan width to the surface. Too wide of a pattern leads to significant overspray and waste. Narrow fans require too many passes, slowing production.
Extend Nozzle Life With Proper Cleaning
Roof coatings contain abrasives that wear nozzle orifices over time. Running coatings without filtering leads to premature wear too.
Here are some maintenance tips:
- Clean tips after each use with a soft brush
- Never use metal picks or objects
- Filter coatings to remove solids
- Start each session with a new or recently cleaned tip
Rotate between a few nozzle sizes to spread out wear over multiple tips. Keep extras on hand for quick swaps when clogs occur.
Proper spray technique also prevents tip clogging:
- Maintain consistent spray distance
- Use high pump pressure
- Apply smooth strokes minimizing dwell
- Cover all surfaces to avoid dry overspray
Implementing these best practices makes nozzles last longer.
In Summary
Nozzle sizing ultimately depends on the output of your pump and thickness of your coating.
Follow roof coating manufacturer guidelines for ideal nozzle openings. Their recommendations take the coating viscosity and best spray application into account.
Testing spray patterns of different fan widths is the best way to dial in technique. Adjust nozzle size gradually until achieving uniform coverage without pumping strain.
Properly sized nozzles that match rig output and coating thickness lead to professional spray application. Take the time to experiment with tips and filters for finding your ultimate roof coating spray setup.