How to Clean an HVLP Spray Gun?

If you’ve invested in an HVLP spray gun, you’ll want to protect that investment by making sure the spray gun lasts as long as possible. The most important thing you can do to extend the life of your HVLP spray gun is to clean it thoroughly after every use. Learn why this matters, how to clean HVLP spray guns, and what solvent to use in the article that follows. 

Why Is It Important to Clean HVLP Spray Guns? 

There are a few important reasons to keep your HVLP spray gun clean. 

• Clean guns last longer. Spray guns are less likely to break down, corrode, or become damaged when they are clean and well-maintained. Spending a few extra minutes to thoroughly clean your spray gun is better than spending a bundle of cash on a new spray set up. 
• Clogged and dirty guns don’t spray well. There are a number of problems you can expect if you try to spray with a gun that wasn’t properly cleaned. For example, if the holes in your air cap are clogged, you’ll get an uneven spray pattern. If your fluid needle is dirty or clogged, your paint may spit instead of spray.
• Early problem detection. If you’re fully disassembling and cleaning your spray gun after every use, you’re going to get to know the parts very well. This will help you spot when components are worn, improperly aligned, or ready for replacement. 

Cleaning an HVLP Spray Gun

Thoroughly cleaning an HVLP spray gun after every use will ensure it lasts for as long as possible. Follow these steps to get in all the nooks and crannies. 

1. Clean immediately after you stop spraying. All finishes are much harder to clean once they have been allowed to dry. Plan your work sessions so that you have plenty of time at the end of the day to thoroughly clean your equipment. 
2. Get a cleaning kit. Cleaning is a lot easier when you have brushes that are designed specifically for HVLP spray guns. These kits are widely available and relatively inexpensive, and even include a bit of lubricant for putting the needle back in the gun. 
3. Put on gloves and goggles. Protect your skin and eyes from accidental splashes by donning appropriate protective gear. Use a comparison chart to find gloves that are compatible with whatever solvent you will be using. 
4. Disconnect the spray gun. Before you start cleaning, the spray gun should be disconnected from the air compressor. Remove any additional pressure regulators attached to the gun. 
5. Clean the paint reservoir. Instead of refilling with paint, pour in an appropriate solvent. (For help choosing a solvent, see the section below.) Reattach the cap, cover the air hole with your finger, and shake the spray gun and paint cup gently, swirling the solvent around inside the cup. 
6. Spray solvent through the machine. Pull the trigger to draw the solvent through the machine. Make sure you have an appropriate container set up to catch the solvent as it comes out. Uncap the paint cup and pour out any remaining solvent, then pull the trigger again until no more liquid comes out. 
7. Wipe down the cup. Dip a lint-free rag in thinner. Use the rag to wipe down the inside and outside of the paint cup as well as the cap. Carefully wipe the threads of the paint cup. Set the paint cup and cap down to dry. 
8. Remove the spray tip. Unscrew the spray tip from the nozzle of the spray gun. Place it in a container filled with solvent.
9. Remove the fluid needle. Unscrew the fluid control knob all the way, being careful to control the spring-loaded needle as you remove the knob. Place the spring, knob, and fluid needle in a safe location. 
10. Remove the air cap. It’s likely that your HVLP spray gun came with a special wrench to remove the air cap. When the air cap is off, place it in the solvent bath with the spray tip and allow it to soak. 
11. Soak the gun and needle. Place the muzzle of the gun in the solvent container to soak. Then, gently guide the fluid needle into the solvent container alongside the gun. The fluid needle will not work if it gets bent, so be extra careful with this delicate piece.
12. Wait. Let the pieces of the HVLP spray gun soak for a minimum of ten minutes. An hour is more appropriate, to give the solvent time to work. Take the fluid needle out of the solvent, wipe it down with a clean rag and set it aside.
13. Scrub. Use the cleaning brushes from your cleaning kit to thoroughly scrub all surfaces of the gun, the air cap, and the spray tip. Make sure to clean finish out of all the holes in the air cap and the spray tip. Anywhere that has been touched by paint or finish should get a good scrubbing. 
14. Dry. When all the paint or finish has been cleaned off, leave the parts on a lint-free cloth to dry. If water was used as a solvent, immediately wipe the parts with a quick-drying solvent such as naphtha or acetone to prevent corrosion. 
15. Reassemble the spray gun. When the parts are dry, reassemble the spray gun and store it in a clean and dry area until the next time you need to paint. Use a bit of lubricant on the fluid needle before reinserting it. 

What Solvent to Use to Clean HVLP Spray Guns

The solvent you use to clean an HVLP spray gun depends on the makeup of the product you were applying.

Waterborne Finishes

For waterborne finishes, warm, soapy water is the appropriate solvent. 

Water can cause corrosion, so as soon as you’re done cleaning, give everything a rinse with a fast-drying solvent. Naphtha and acetone are two good options. 

Oil-based Finishes

Mineral spirits are an effective solvent for nearly all non-water-based finishes. However, it can be somewhat expensive. Paint thinner is essentially a less purified version of mineral spirits and often works just as well. Acetone can also be used. 

Conclusion

HVLP spray guns should be disassembled and thoroughly cleaned after every use. For waterborne finishes, you can use soap and water as the solvent to clean an HVLP spray gun. For oil-based finishes, clean your HVLP spray gun with mineral spirits, paint thinner, acetone, or another appropriate solvent.