Introduction
If you regularly work with polyurethane foam spray guns, you know how even small issues like leaks, clogs, or uneven spray can cause major setbacks. The good news? These common problems are easy to fix — when you know how.
Drawing on over 12 years of expertise in équipement de pulvérisation de mousse de polyuréthane sales and service, UREXCEED have put together this guide packed with practical, field-tested solutions. Whether you’re a seasoned contractor or a new field technician, these troubleshooting tips will help you extend the life of your spray gun and achieve better spray results.
Why Is My Spray Gun Leaking? (Common Causes + Solutions)
Leaking spray guns are usually caused by:
1. Worn or Damaged Seals
O-rings and gaskets naturally wear out, deform, or crack over time, leading to leaks.
Solution: Regularly inspect and replace any aging or damaged seals.
Conseil de pro : Apply a small amount of petroleum jelly when installing new O-rings — it helps with installation and significantly extends their life.
🔧 Need spare seals? Every UREXCEED PU spray foam machine comes with a complete toolkit, including extra O-rings and gaskets. Running low? Our sales team can dispatch accessories within 24 hours to minimize your downtime.
2. Loose Connections
Loose fittings between the gun and hoses can cause leaks.
Solution: Inspect all threaded connections and tighten as needed. For a secure seal, use thread seal tape or a thread-locking compound. (Yes, our toolkit includes thread tape!)
3. Material Buildup in the Mixing Chamber
Solution: Clear out any clogged auxiliary ports. If the gun is severely blocked, fully disassemble it and clean out all passages — sometimes drilling through hardened residue is necessary.
Prevention Tip: After every job, clean the gun thoroughly, release all air pressure, and apply petroleum jelly over the feed block and nozzle. This blocks air exposure and prevents residue buildup — a secret weapon for extending equipment life.
4. Internal Corrosion or Damage
If internal passages are corroded or cracked, you’ll need to replace parts like the valve body or inner tube.
Prevention Tip: Invest in quality guns made from corrosion-resistant materials. At Urexceed, our mixing chambers and friction parts are made with specially treated imported alloys to stand the test of time.
How to Fix a Clogged Foam Spray Gun
Clogs are mainly caused by:
1. Incomplete Cleaning After Use
If leftover material isn’t flushed out properly, it will cure inside the hoses or gun.
Solution: After every use, flush the system thoroughly with polyurethane-safe cleaning agents like DOP, MIBK, or designated cleaners.
2. Poor-Quality, Expired, or Contaminated Materials
Low-quality or moisture-exposed materials can trigger blockages quickly.
Solution: Always choose high-quality materials and store them sealed, away from moisture and extreme heat.
🌟 Looking for reliable foam materials? Urexceed offers customized formulations designed for different climates, fire ratings, and project types.
How to Quickly Solve Uneven Spray or Poor Atomization?
Poor atomization typically happens because of:
1. Uneven A/B Material Pressure or Ratios
A pressure mismatch between the ISO and polyol components, or partial blockages in the mixing chamber, can disrupt atomization.
Solution: Monitor pressure levels, clear blockages promptly, and clean thoroughly. If pressure issues originate from the machine, inspect and replace feed pumps or related components.
2. Unstable Spray Pressure
If the air pressure feeding your gun is too low or unstable, spray quality will suffer.
Solution: Maintain proper machine pressure and replace the high-pressure pump if necessary.
3. Temperature Problems
Spraying with materials that are too cold — or in extreme environmental temperatures (ideal range: 15°C–30°C / 59°F–86°F) — leads to poor atomization.
Solution: Use barrel heaters to keep material temperatures optimal, especially critical in colder regions like Canada or Australia.
4. Nozzle Wear or Blockage
Uneven spray or dripping foam often signals a worn or clogged nozzle.
Solution: Clean nozzles regularly and replace them every 100 operating hours or sooner if you notice deformation.
5. Improper Spraying Technique
New operators often struggle with maintaining consistent distance, speed, and angle.
Basic Guidelines:
Hold the gun vertical or tilted slightly forward (about 15°).
Maintain a distance of 18–24 inches from the surface.
Move at 30–50 cm/sec (about 12–20 inches/sec) with 10–30% overlap between passes.
🎯 Conseil de pro : Match your nozzle size to your application — finer nozzles for detail work, high-flow nozzles for large surfaces.
Proactive Maintenance Tips for Spray Guns
Perform a deep clean at least once a week.
Inspect hoses, seals, and fittings regularly for wear.
Store the spray gun in a clean, dry environment away from extreme temperatures.
Use a desiccant dryer in your air supply to prevent water contamination.
🛡️ Did you know?
Proper maintenance can extend your spray gun’s service life by 3–5 times!
Conclusion
Fixing leaks, clogs, and spray pattern issues doesn’t have to be complicated. With a little know-how and a regular maintenance routine, you can minimize downtime, reduce repair costs, and consistently achieve professional spray results.
Common Questions About Spray Foam Guns
Q: How often should I clean my spray gun?
A: After every use. Daily cleaning is critical to preventing clogs and premature wear.
Q: What’s the best cleaning solvent?
A: Always use polyurethane-specific cleaning agents recommended by your equipment manufacturer — avoid general-purpose cleaners like WD-40.
Q: How do I know when to replace my spray nozzle?
A: Replace the nozzle if you notice uneven spray patterns, dripping, or material buildup that cleaning doesn’t fix.
About the Author
Urexceed is a certified expert in polyurethane foam equipment and applications with over 12 years of experience in the industry. We’ve helped hundreds of contractors and individual users deliver flawless spray foam results through expert training, maintenance support, and customized equipment solutions.
Beyond top-quality spray machines and materials, Urexceed also offers full after-sales support, including free toolkits, detailed manuals, and a 24-hour online service team.
When you choose Urexceed, you spray with confidence.
👉 Connect with Urexceed on info@urexceed.com or call +8613656166310 for personalized support.