Cavitation: What It Is and How to Prevent It

If you’ve ever noticed your spray rig rod slamming down during a stroke, you may be dealing with cavitation. On single-leg and plural-component rigs, this is often caused by air trapped in the system. Understanding why it happens and how to prevent it can save you from inconsistent flow, poor spray quality, and potential pump damage.

Cavitation occurs when there isn’t enough material in the cylinder to cushion the rod on the downstroke. In both single-leg and plural-component setups, trapped air naturally moves to the top of the cylinder. If the material is too thick due to temperature, or the supply is too low, the cylinder may not fill completely. When this happens, the rod hits the cylinder bottom violently instead of moving smoothly.

Temperature plays a key role. Material that is too cold flows slower, making it harder for the cylinder to fill fully. Keeping material at the recommended temperature ensures it moves easier and decreases the chance of air pockets forming. Similarly, maintaining an adequate supply in your tanks is essential. Low material levels starve the pump, creating gaps in the flow that can trigger cavitation.

For single-legs, you can take additional steps to prevent air from building up. Use the prime valve to release trapped air and the cylinders will fill completely. Listening to your pump strokes is another simple check; smooth, rhythmic movement usually indicates proper cylinder fill and material flow, while inconsistent strokes can signal a problem.

Plural-component rigs follow the same basic principles, but with two or more materials, getting everything balanced and flowing correctly is crucial. When you first prime your rig in the morning, you may notice small cavitations as the system warms up and the cylinders fill. Material temperatures need to be at the recommended level, and each leg must have a consistent flow. Until everything is fully primed and the material is flowing smoothly, air pockets or incomplete cylinder fill can cause minor cavitation. Taking a few minutes to get your rig properly up to temperature and fully primed helps prevent these early hiccups and sets you up for consistent, smooth spraying.

In summary, preventing cavitation on single-leg and plural-component rigs comes down to these things: keeping enough material at the right temperature and eliminating air from the system. By paying attention to these factors, you’ll achieve smoother strokes, better spray quality, and longer-lasting equipment.